Reticulum/docs/manual/examples.html
2021-12-08 20:42:48 +01:00

2378 lines
241 KiB
HTML
Raw Permalink Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Code Examples &#8212; Reticulum Network Stack 0.3.0 beta documentation</title>
<link rel="stylesheet" type="text/css" href="_static/pygments.css" />
<link rel="stylesheet" type="text/css" href="_static/classic.css" />
<script data-url_root="./" id="documentation_options" src="_static/documentation_options.js"></script>
<script src="_static/jquery.js"></script>
<script src="_static/underscore.js"></script>
<script src="_static/doctools.js"></script>
<link rel="index" title="Index" href="genindex.html" />
<link rel="search" title="Search" href="search.html" />
<link rel="prev" title="API Reference" href="reference.html" />
</head><body>
<div class="related" role="navigation" aria-label="related navigation">
<h3>Navigation</h3>
<ul>
<li class="right" style="margin-right: 10px">
<a href="genindex.html" title="General Index"
accesskey="I">index</a></li>
<li class="right" >
<a href="reference.html" title="API Reference"
accesskey="P">previous</a> |</li>
<li class="nav-item nav-item-0"><a href="index.html">Reticulum Network Stack 0.3.0 beta documentation</a> &#187;</li>
<li class="nav-item nav-item-this"><a href="">Code Examples</a></li>
</ul>
</div>
<div class="document">
<div class="documentwrapper">
<div class="bodywrapper">
<div class="body" role="main">
<div class="section" id="code-examples">
<span id="examples-main"></span><h1>Code Examples<a class="headerlink" href="#code-examples" title="Permalink to this headline"></a></h1>
<p>A number of examples are included in the source distribution of Reticulum.
You can use these examples to learn how to write your own programs.</p>
<div class="section" id="minimal">
<span id="example-minimal"></span><h2>Minimal<a class="headerlink" href="#minimal" title="Permalink to this headline"></a></h2>
<p>The <em>Minimal</em> example demonstrates the bare-minimum setup required to connect to
a Reticulum network from your program. In about five lines of code, you will
have the Reticulum Network Stack initialised, and ready to pass traffic in your
program.</p>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="c1">##########################################################</span>
<span class="c1"># This RNS example demonstrates a minimal setup, that #</span>
<span class="c1"># will start up the Reticulum Network Stack, generate a #</span>
<span class="c1"># new destination, and let the user send an announce. #</span>
<span class="c1">##########################################################</span>
<span class="kn">import</span> <span class="nn">argparse</span>
<span class="kn">import</span> <span class="nn">RNS</span>
<span class="c1"># Let&#39;s define an app name. We&#39;ll use this for all</span>
<span class="c1"># destinations we create. Since this basic example</span>
<span class="c1"># is part of a range of example utilities, we&#39;ll put</span>
<span class="c1"># them all within the app namespace &quot;example_utilities&quot;</span>
<span class="n">APP_NAME</span> <span class="o">=</span> <span class="s2">&quot;example_utilities&quot;</span>
<span class="c1"># This initialisation is executed when the program is started</span>
<span class="k">def</span> <span class="nf">program_setup</span><span class="p">(</span><span class="n">configpath</span><span class="p">):</span>
<span class="c1"># We must first initialise Reticulum</span>
<span class="n">reticulum</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Reticulum</span><span class="p">(</span><span class="n">configpath</span><span class="p">)</span>
<span class="c1"># Randomly create a new identity for our example</span>
<span class="n">identity</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Identity</span><span class="p">()</span>
<span class="c1"># Using the identity we just created, we create a destination.</span>
<span class="c1"># Destinations are endpoints in Reticulum, that can be addressed</span>
<span class="c1"># and communicated with. Destinations can also announce their</span>
<span class="c1"># existence, which will let the network know they are reachable</span>
<span class="c1"># and autoomatically create paths to them, from anywhere else</span>
<span class="c1"># in the network.</span>
<span class="n">destination</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="p">(</span>
<span class="n">identity</span><span class="p">,</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">IN</span><span class="p">,</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">SINGLE</span><span class="p">,</span>
<span class="n">APP_NAME</span><span class="p">,</span>
<span class="s2">&quot;minimalsample&quot;</span>
<span class="p">)</span>
<span class="c1"># We configure the destination to automatically prove all</span>
<span class="c1"># packets adressed to it. By doing this, RNS will automatically</span>
<span class="c1"># generate a proof for each incoming packet and transmit it</span>
<span class="c1"># back to the sender of that packet. This will let anyone that</span>
<span class="c1"># tries to communicate with the destination know whether their</span>
<span class="c1"># communication was received correctly.</span>
<span class="n">destination</span><span class="o">.</span><span class="n">set_proof_strategy</span><span class="p">(</span><span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">PROVE_ALL</span><span class="p">)</span>
<span class="c1"># Everything&#39;s ready!</span>
<span class="c1"># Let&#39;s hand over control to the announce loop</span>
<span class="n">announceLoop</span><span class="p">(</span><span class="n">destination</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">announceLoop</span><span class="p">(</span><span class="n">destination</span><span class="p">):</span>
<span class="c1"># Let the user know that everything is ready</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span>
<span class="s2">&quot;Minimal example &quot;</span><span class="o">+</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">prettyhexrep</span><span class="p">(</span><span class="n">destination</span><span class="o">.</span><span class="n">hash</span><span class="p">)</span><span class="o">+</span>
<span class="s2">&quot; running, hit enter to manually send an announce (Ctrl-C to quit)&quot;</span>
<span class="p">)</span>
<span class="c1"># We enter a loop that runs until the users exits.</span>
<span class="c1"># If the user hits enter, we will announce our server</span>
<span class="c1"># destination on the network, which will let clients</span>
<span class="c1"># know how to create messages directed towards it.</span>
<span class="k">while</span> <span class="kc">True</span><span class="p">:</span>
<span class="n">entered</span> <span class="o">=</span> <span class="nb">input</span><span class="p">()</span>
<span class="n">destination</span><span class="o">.</span><span class="n">announce</span><span class="p">()</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Sent announce from &quot;</span><span class="o">+</span><span class="n">RNS</span><span class="o">.</span><span class="n">prettyhexrep</span><span class="p">(</span><span class="n">destination</span><span class="o">.</span><span class="n">hash</span><span class="p">))</span>
<span class="c1">##########################################################</span>
<span class="c1">#### Program Startup #####################################</span>
<span class="c1">##########################################################</span>
<span class="c1"># This part of the program gets run at startup,</span>
<span class="c1"># and parses input from the user, and then starts</span>
<span class="c1"># the desired program mode.</span>
<span class="k">if</span> <span class="vm">__name__</span> <span class="o">==</span> <span class="s2">&quot;__main__&quot;</span><span class="p">:</span>
<span class="k">try</span><span class="p">:</span>
<span class="n">parser</span> <span class="o">=</span> <span class="n">argparse</span><span class="o">.</span><span class="n">ArgumentParser</span><span class="p">(</span>
<span class="n">description</span><span class="o">=</span><span class="s2">&quot;Minimal example to start Reticulum and create a destination&quot;</span>
<span class="p">)</span>
<span class="n">parser</span><span class="o">.</span><span class="n">add_argument</span><span class="p">(</span>
<span class="s2">&quot;--config&quot;</span><span class="p">,</span>
<span class="n">action</span><span class="o">=</span><span class="s2">&quot;store&quot;</span><span class="p">,</span>
<span class="n">default</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span>
<span class="n">help</span><span class="o">=</span><span class="s2">&quot;path to alternative Reticulum config directory&quot;</span><span class="p">,</span>
<span class="nb">type</span><span class="o">=</span><span class="nb">str</span>
<span class="p">)</span>
<span class="n">args</span> <span class="o">=</span> <span class="n">parser</span><span class="o">.</span><span class="n">parse_args</span><span class="p">()</span>
<span class="k">if</span> <span class="n">args</span><span class="o">.</span><span class="n">config</span><span class="p">:</span>
<span class="n">configarg</span> <span class="o">=</span> <span class="n">args</span><span class="o">.</span><span class="n">config</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">configarg</span> <span class="o">=</span> <span class="kc">None</span>
<span class="n">program_setup</span><span class="p">(</span><span class="n">configarg</span><span class="p">)</span>
<span class="k">except</span> <span class="ne">KeyboardInterrupt</span><span class="p">:</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="n">exit</span><span class="p">()</span>
</pre></div>
</div>
<p>This example can also be found at <a class="reference external" href="https://github.com/markqvist/Reticulum/blob/master/Examples/Minimal.py">https://github.com/markqvist/Reticulum/blob/master/Examples/Minimal.py</a>.</p>
</div>
<div class="section" id="announce">
<span id="example-announce"></span><h2>Announce<a class="headerlink" href="#announce" title="Permalink to this headline"></a></h2>
<p>The <em>Announce</em> example builds upon the previous example by exploring how to
announce a destination on the network, and how to let your program receive
notifications about announces from relevant destinations.</p>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="c1">##########################################################</span>
<span class="c1"># This RNS example demonstrates setting up announce #</span>
<span class="c1"># callbacks, which will let an application receive a #</span>
<span class="c1"># notification when an announce relevant for it arrives #</span>
<span class="c1">##########################################################</span>
<span class="kn">import</span> <span class="nn">argparse</span>
<span class="kn">import</span> <span class="nn">random</span>
<span class="kn">import</span> <span class="nn">RNS</span>
<span class="c1"># Let&#39;s define an app name. We&#39;ll use this for all</span>
<span class="c1"># destinations we create. Since this basic example</span>
<span class="c1"># is part of a range of example utilities, we&#39;ll put</span>
<span class="c1"># them all within the app namespace &quot;example_utilities&quot;</span>
<span class="n">APP_NAME</span> <span class="o">=</span> <span class="s2">&quot;example_utilities&quot;</span>
<span class="c1"># We initialise two lists of strings to use as app_data</span>
<span class="n">fruits</span> <span class="o">=</span> <span class="p">[</span><span class="s2">&quot;Peach&quot;</span><span class="p">,</span> <span class="s2">&quot;Quince&quot;</span><span class="p">,</span> <span class="s2">&quot;Date&quot;</span><span class="p">,</span> <span class="s2">&quot;Tangerine&quot;</span><span class="p">,</span> <span class="s2">&quot;Pomelo&quot;</span><span class="p">,</span> <span class="s2">&quot;Carambola&quot;</span><span class="p">,</span> <span class="s2">&quot;Grape&quot;</span><span class="p">]</span>
<span class="n">noble_gases</span> <span class="o">=</span> <span class="p">[</span><span class="s2">&quot;Helium&quot;</span><span class="p">,</span> <span class="s2">&quot;Neon&quot;</span><span class="p">,</span> <span class="s2">&quot;Argon&quot;</span><span class="p">,</span> <span class="s2">&quot;Krypton&quot;</span><span class="p">,</span> <span class="s2">&quot;Xenon&quot;</span><span class="p">,</span> <span class="s2">&quot;Radon&quot;</span><span class="p">,</span> <span class="s2">&quot;Oganesson&quot;</span><span class="p">]</span>
<span class="c1"># This initialisation is executed when the program is started</span>
<span class="k">def</span> <span class="nf">program_setup</span><span class="p">(</span><span class="n">configpath</span><span class="p">):</span>
<span class="c1"># We must first initialise Reticulum</span>
<span class="n">reticulum</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Reticulum</span><span class="p">(</span><span class="n">configpath</span><span class="p">)</span>
<span class="c1"># Randomly create a new identity for our example</span>
<span class="n">identity</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Identity</span><span class="p">()</span>
<span class="c1"># Using the identity we just created, we create two destinations</span>
<span class="c1"># in the &quot;example_utilities.announcesample&quot; application space.</span>
<span class="c1">#</span>
<span class="c1"># Destinations are endpoints in Reticulum, that can be addressed</span>
<span class="c1"># and communicated with. Destinations can also announce their</span>
<span class="c1"># existence, which will let the network know they are reachable</span>
<span class="c1"># and autoomatically create paths to them, from anywhere else</span>
<span class="c1"># in the network.</span>
<span class="n">destination_1</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="p">(</span>
<span class="n">identity</span><span class="p">,</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">IN</span><span class="p">,</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">SINGLE</span><span class="p">,</span>
<span class="n">APP_NAME</span><span class="p">,</span>
<span class="s2">&quot;announcesample&quot;</span><span class="p">,</span>
<span class="s2">&quot;fruits&quot;</span>
<span class="p">)</span>
<span class="n">destination_2</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="p">(</span>
<span class="n">identity</span><span class="p">,</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">IN</span><span class="p">,</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">SINGLE</span><span class="p">,</span>
<span class="n">APP_NAME</span><span class="p">,</span>
<span class="s2">&quot;announcesample&quot;</span><span class="p">,</span>
<span class="s2">&quot;noble_gases&quot;</span>
<span class="p">)</span>
<span class="c1"># We configure the destinations to automatically prove all</span>
<span class="c1"># packets adressed to it. By doing this, RNS will automatically</span>
<span class="c1"># generate a proof for each incoming packet and transmit it</span>
<span class="c1"># back to the sender of that packet. This will let anyone that</span>
<span class="c1"># tries to communicate with the destination know whether their</span>
<span class="c1"># communication was received correctly.</span>
<span class="n">destination_1</span><span class="o">.</span><span class="n">set_proof_strategy</span><span class="p">(</span><span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">PROVE_ALL</span><span class="p">)</span>
<span class="n">destination_2</span><span class="o">.</span><span class="n">set_proof_strategy</span><span class="p">(</span><span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">PROVE_ALL</span><span class="p">)</span>
<span class="c1"># We create an announce handler and configure it to only ask for</span>
<span class="c1"># announces from &quot;example_utilities.announcesample.fruits&quot;.</span>
<span class="c1"># Try changing the filter and see what happens.</span>
<span class="n">announce_handler</span> <span class="o">=</span> <span class="n">ExampleAnnounceHandler</span><span class="p">(</span>
<span class="n">aspect_filter</span><span class="o">=</span><span class="s2">&quot;example_utilities.announcesample.fruits&quot;</span>
<span class="p">)</span>
<span class="c1"># We register the announce handler with Reticulum</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Transport</span><span class="o">.</span><span class="n">register_announce_handler</span><span class="p">(</span><span class="n">announce_handler</span><span class="p">)</span>
<span class="c1"># Everything&#39;s ready!</span>
<span class="c1"># Let&#39;s hand over control to the announce loop</span>
<span class="n">announceLoop</span><span class="p">(</span><span class="n">destination_1</span><span class="p">,</span> <span class="n">destination_2</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">announceLoop</span><span class="p">(</span><span class="n">destination_1</span><span class="p">,</span> <span class="n">destination_2</span><span class="p">):</span>
<span class="c1"># Let the user know that everything is ready</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Announce example running, hit enter to manually send an announce (Ctrl-C to quit)&quot;</span><span class="p">)</span>
<span class="c1"># We enter a loop that runs until the users exits.</span>
<span class="c1"># If the user hits enter, we will announce our server</span>
<span class="c1"># destination on the network, which will let clients</span>
<span class="c1"># know how to create messages directed towards it.</span>
<span class="k">while</span> <span class="kc">True</span><span class="p">:</span>
<span class="n">entered</span> <span class="o">=</span> <span class="nb">input</span><span class="p">()</span>
<span class="c1"># Randomly select a fruit</span>
<span class="n">fruit</span> <span class="o">=</span> <span class="n">fruits</span><span class="p">[</span><span class="n">random</span><span class="o">.</span><span class="n">randint</span><span class="p">(</span><span class="mi">0</span><span class="p">,</span><span class="nb">len</span><span class="p">(</span><span class="n">fruits</span><span class="p">)</span><span class="o">-</span><span class="mi">1</span><span class="p">)]</span>
<span class="c1"># Send the announce including the app data</span>
<span class="n">destination_1</span><span class="o">.</span><span class="n">announce</span><span class="p">(</span><span class="n">app_data</span><span class="o">=</span><span class="n">fruit</span><span class="o">.</span><span class="n">encode</span><span class="p">(</span><span class="s2">&quot;utf-8&quot;</span><span class="p">))</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span>
<span class="s2">&quot;Sent announce from &quot;</span><span class="o">+</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">prettyhexrep</span><span class="p">(</span><span class="n">destination_1</span><span class="o">.</span><span class="n">hash</span><span class="p">)</span><span class="o">+</span>
<span class="s2">&quot; (&quot;</span><span class="o">+</span><span class="n">destination_1</span><span class="o">.</span><span class="n">name</span><span class="o">+</span><span class="s2">&quot;)&quot;</span>
<span class="p">)</span>
<span class="c1"># Randomly select a noble gas</span>
<span class="n">noble_gas</span> <span class="o">=</span> <span class="n">noble_gases</span><span class="p">[</span><span class="n">random</span><span class="o">.</span><span class="n">randint</span><span class="p">(</span><span class="mi">0</span><span class="p">,</span><span class="nb">len</span><span class="p">(</span><span class="n">noble_gases</span><span class="p">)</span><span class="o">-</span><span class="mi">1</span><span class="p">)]</span>
<span class="c1"># Send the announce including the app data</span>
<span class="n">destination_2</span><span class="o">.</span><span class="n">announce</span><span class="p">(</span><span class="n">app_data</span><span class="o">=</span><span class="n">noble_gas</span><span class="o">.</span><span class="n">encode</span><span class="p">(</span><span class="s2">&quot;utf-8&quot;</span><span class="p">))</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span>
<span class="s2">&quot;Sent announce from &quot;</span><span class="o">+</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">prettyhexrep</span><span class="p">(</span><span class="n">destination_2</span><span class="o">.</span><span class="n">hash</span><span class="p">)</span><span class="o">+</span>
<span class="s2">&quot; (&quot;</span><span class="o">+</span><span class="n">destination_2</span><span class="o">.</span><span class="n">name</span><span class="o">+</span><span class="s2">&quot;)&quot;</span>
<span class="p">)</span>
<span class="c1"># We will need to define an announce handler class that</span>
<span class="c1"># Reticulum can message when an announce arrives.</span>
<span class="k">class</span> <span class="nc">ExampleAnnounceHandler</span><span class="p">:</span>
<span class="c1"># The initialisation method takes the optional</span>
<span class="c1"># aspect_filter argument. If aspect_filter is set to</span>
<span class="c1"># None, all announces will be passed to the instance.</span>
<span class="c1"># If only some announces are wanted, it can be set to</span>
<span class="c1"># an aspect string.</span>
<span class="k">def</span> <span class="fm">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">aspect_filter</span><span class="o">=</span><span class="kc">None</span><span class="p">):</span>
<span class="bp">self</span><span class="o">.</span><span class="n">aspect_filter</span> <span class="o">=</span> <span class="n">aspect_filter</span>
<span class="c1"># This method will be called by Reticulums Transport</span>
<span class="c1"># system when an announce arrives that matches the</span>
<span class="c1"># configured aspect filter. Filters must be specific,</span>
<span class="c1"># and cannot use wildcards.</span>
<span class="k">def</span> <span class="nf">received_announce</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">destination_hash</span><span class="p">,</span> <span class="n">announced_identity</span><span class="p">,</span> <span class="n">app_data</span><span class="p">):</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span>
<span class="s2">&quot;Received an announce from &quot;</span><span class="o">+</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">prettyhexrep</span><span class="p">(</span><span class="n">destination_hash</span><span class="p">)</span>
<span class="p">)</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span>
<span class="s2">&quot;The announce contained the following app data: &quot;</span><span class="o">+</span>
<span class="n">app_data</span><span class="o">.</span><span class="n">decode</span><span class="p">(</span><span class="s2">&quot;utf-8&quot;</span><span class="p">)</span>
<span class="p">)</span>
<span class="c1">##########################################################</span>
<span class="c1">#### Program Startup #####################################</span>
<span class="c1">##########################################################</span>
<span class="c1"># This part of the program gets run at startup,</span>
<span class="c1"># and parses input from the user, and then starts</span>
<span class="c1"># the desired program mode.</span>
<span class="k">if</span> <span class="vm">__name__</span> <span class="o">==</span> <span class="s2">&quot;__main__&quot;</span><span class="p">:</span>
<span class="k">try</span><span class="p">:</span>
<span class="n">parser</span> <span class="o">=</span> <span class="n">argparse</span><span class="o">.</span><span class="n">ArgumentParser</span><span class="p">(</span>
<span class="n">description</span><span class="o">=</span><span class="s2">&quot;Reticulum example that demonstrates announces and announce handlers&quot;</span>
<span class="p">)</span>
<span class="n">parser</span><span class="o">.</span><span class="n">add_argument</span><span class="p">(</span>
<span class="s2">&quot;--config&quot;</span><span class="p">,</span>
<span class="n">action</span><span class="o">=</span><span class="s2">&quot;store&quot;</span><span class="p">,</span>
<span class="n">default</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span>
<span class="n">help</span><span class="o">=</span><span class="s2">&quot;path to alternative Reticulum config directory&quot;</span><span class="p">,</span>
<span class="nb">type</span><span class="o">=</span><span class="nb">str</span>
<span class="p">)</span>
<span class="n">args</span> <span class="o">=</span> <span class="n">parser</span><span class="o">.</span><span class="n">parse_args</span><span class="p">()</span>
<span class="k">if</span> <span class="n">args</span><span class="o">.</span><span class="n">config</span><span class="p">:</span>
<span class="n">configarg</span> <span class="o">=</span> <span class="n">args</span><span class="o">.</span><span class="n">config</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">configarg</span> <span class="o">=</span> <span class="kc">None</span>
<span class="n">program_setup</span><span class="p">(</span><span class="n">configarg</span><span class="p">)</span>
<span class="k">except</span> <span class="ne">KeyboardInterrupt</span><span class="p">:</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="n">exit</span><span class="p">()</span>
</pre></div>
</div>
<p>This example can also be found at <a class="reference external" href="https://github.com/markqvist/Reticulum/blob/master/Examples/Announce.py">https://github.com/markqvist/Reticulum/blob/master/Examples/Announce.py</a>.</p>
</div>
<div class="section" id="broadcast">
<span id="example-broadcast"></span><h2>Broadcast<a class="headerlink" href="#broadcast" title="Permalink to this headline"></a></h2>
<p>The <em>Broadcast</em> example explores how to transmit plaintext broadcast messages
over the network.</p>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="c1">##########################################################</span>
<span class="c1"># This RNS example demonstrates broadcasting unencrypted #</span>
<span class="c1"># information to any listening destinations. #</span>
<span class="c1">##########################################################</span>
<span class="kn">import</span> <span class="nn">sys</span>
<span class="kn">import</span> <span class="nn">argparse</span>
<span class="kn">import</span> <span class="nn">RNS</span>
<span class="c1"># Let&#39;s define an app name. We&#39;ll use this for all</span>
<span class="c1"># destinations we create. Since this basic example</span>
<span class="c1"># is part of a range of example utilities, we&#39;ll put</span>
<span class="c1"># them all within the app namespace &quot;example_utilities&quot;</span>
<span class="n">APP_NAME</span> <span class="o">=</span> <span class="s2">&quot;example_utilities&quot;</span>
<span class="c1"># This initialisation is executed when the program is started</span>
<span class="k">def</span> <span class="nf">program_setup</span><span class="p">(</span><span class="n">configpath</span><span class="p">,</span> <span class="n">channel</span><span class="o">=</span><span class="kc">None</span><span class="p">):</span>
<span class="c1"># We must first initialise Reticulum</span>
<span class="n">reticulum</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Reticulum</span><span class="p">(</span><span class="n">configpath</span><span class="p">)</span>
<span class="c1"># If the user did not select a &quot;channel&quot; we use</span>
<span class="c1"># a default one called &quot;public_information&quot;.</span>
<span class="c1"># This &quot;channel&quot; is added to the destination name-</span>
<span class="c1"># space, so the user can select different broadcast</span>
<span class="c1"># channels.</span>
<span class="k">if</span> <span class="n">channel</span> <span class="o">==</span> <span class="kc">None</span><span class="p">:</span>
<span class="n">channel</span> <span class="o">=</span> <span class="s2">&quot;public_information&quot;</span>
<span class="c1"># We create a PLAIN destination. This is an uncencrypted endpoint</span>
<span class="c1"># that anyone can listen to and send information to.</span>
<span class="n">broadcast_destination</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="p">(</span>
<span class="kc">None</span><span class="p">,</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">IN</span><span class="p">,</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">PLAIN</span><span class="p">,</span>
<span class="n">APP_NAME</span><span class="p">,</span>
<span class="s2">&quot;broadcast&quot;</span><span class="p">,</span>
<span class="n">channel</span>
<span class="p">)</span>
<span class="c1"># We specify a callback that will get called every time</span>
<span class="c1"># the destination receives data.</span>
<span class="n">broadcast_destination</span><span class="o">.</span><span class="n">set_packet_callback</span><span class="p">(</span><span class="n">packet_callback</span><span class="p">)</span>
<span class="c1"># Everything&#39;s ready!</span>
<span class="c1"># Let&#39;s hand over control to the main loop</span>
<span class="n">broadcastLoop</span><span class="p">(</span><span class="n">broadcast_destination</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">packet_callback</span><span class="p">(</span><span class="n">data</span><span class="p">,</span> <span class="n">packet</span><span class="p">):</span>
<span class="c1"># Simply print out the received data</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;Received data: &quot;</span><span class="o">+</span><span class="n">data</span><span class="o">.</span><span class="n">decode</span><span class="p">(</span><span class="s2">&quot;utf-8&quot;</span><span class="p">)</span><span class="o">+</span><span class="s2">&quot;</span><span class="se">\r\n</span><span class="s2">&gt; &quot;</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="n">sys</span><span class="o">.</span><span class="n">stdout</span><span class="o">.</span><span class="n">flush</span><span class="p">()</span>
<span class="k">def</span> <span class="nf">broadcastLoop</span><span class="p">(</span><span class="n">destination</span><span class="p">):</span>
<span class="c1"># Let the user know that everything is ready</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span>
<span class="s2">&quot;Broadcast example &quot;</span><span class="o">+</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">prettyhexrep</span><span class="p">(</span><span class="n">destination</span><span class="o">.</span><span class="n">hash</span><span class="p">)</span><span class="o">+</span>
<span class="s2">&quot; running, enter text and hit enter to broadcast (Ctrl-C to quit)&quot;</span>
<span class="p">)</span>
<span class="c1"># We enter a loop that runs until the users exits.</span>
<span class="c1"># If the user hits enter, we will send the information</span>
<span class="c1"># that the user entered into the prompt.</span>
<span class="k">while</span> <span class="kc">True</span><span class="p">:</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&gt; &quot;</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="n">entered</span> <span class="o">=</span> <span class="nb">input</span><span class="p">()</span>
<span class="k">if</span> <span class="n">entered</span> <span class="o">!=</span> <span class="s2">&quot;&quot;</span><span class="p">:</span>
<span class="n">data</span> <span class="o">=</span> <span class="n">entered</span><span class="o">.</span><span class="n">encode</span><span class="p">(</span><span class="s2">&quot;utf-8&quot;</span><span class="p">)</span>
<span class="n">packet</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Packet</span><span class="p">(</span><span class="n">destination</span><span class="p">,</span> <span class="n">data</span><span class="p">)</span>
<span class="n">packet</span><span class="o">.</span><span class="n">send</span><span class="p">()</span>
<span class="c1">##########################################################</span>
<span class="c1">#### Program Startup #####################################</span>
<span class="c1">##########################################################</span>
<span class="c1"># This part of the program gets run at startup,</span>
<span class="c1"># and parses input from the user, and then starts</span>
<span class="c1"># the program.</span>
<span class="k">if</span> <span class="vm">__name__</span> <span class="o">==</span> <span class="s2">&quot;__main__&quot;</span><span class="p">:</span>
<span class="k">try</span><span class="p">:</span>
<span class="n">parser</span> <span class="o">=</span> <span class="n">argparse</span><span class="o">.</span><span class="n">ArgumentParser</span><span class="p">(</span>
<span class="n">description</span><span class="o">=</span><span class="s2">&quot;Reticulum example demonstrating sending and receiving broadcasts&quot;</span>
<span class="p">)</span>
<span class="n">parser</span><span class="o">.</span><span class="n">add_argument</span><span class="p">(</span>
<span class="s2">&quot;--config&quot;</span><span class="p">,</span>
<span class="n">action</span><span class="o">=</span><span class="s2">&quot;store&quot;</span><span class="p">,</span>
<span class="n">default</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span>
<span class="n">help</span><span class="o">=</span><span class="s2">&quot;path to alternative Reticulum config directory&quot;</span><span class="p">,</span>
<span class="nb">type</span><span class="o">=</span><span class="nb">str</span>
<span class="p">)</span>
<span class="n">parser</span><span class="o">.</span><span class="n">add_argument</span><span class="p">(</span>
<span class="s2">&quot;--channel&quot;</span><span class="p">,</span>
<span class="n">action</span><span class="o">=</span><span class="s2">&quot;store&quot;</span><span class="p">,</span>
<span class="n">default</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span>
<span class="n">help</span><span class="o">=</span><span class="s2">&quot;broadcast channel name&quot;</span><span class="p">,</span>
<span class="nb">type</span><span class="o">=</span><span class="nb">str</span>
<span class="p">)</span>
<span class="n">args</span> <span class="o">=</span> <span class="n">parser</span><span class="o">.</span><span class="n">parse_args</span><span class="p">()</span>
<span class="k">if</span> <span class="n">args</span><span class="o">.</span><span class="n">config</span><span class="p">:</span>
<span class="n">configarg</span> <span class="o">=</span> <span class="n">args</span><span class="o">.</span><span class="n">config</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">configarg</span> <span class="o">=</span> <span class="kc">None</span>
<span class="k">if</span> <span class="n">args</span><span class="o">.</span><span class="n">channel</span><span class="p">:</span>
<span class="n">channelarg</span> <span class="o">=</span> <span class="n">args</span><span class="o">.</span><span class="n">channel</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">channelarg</span> <span class="o">=</span> <span class="kc">None</span>
<span class="n">program_setup</span><span class="p">(</span><span class="n">configarg</span><span class="p">,</span> <span class="n">channelarg</span><span class="p">)</span>
<span class="k">except</span> <span class="ne">KeyboardInterrupt</span><span class="p">:</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="n">exit</span><span class="p">()</span>
</pre></div>
</div>
<p>This example can also be found at <a class="reference external" href="https://github.com/markqvist/Reticulum/blob/master/Examples/Broadcast.py">https://github.com/markqvist/Reticulum/blob/master/Examples/Broadcast.py</a>.</p>
</div>
<div class="section" id="echo">
<span id="example-echo"></span><h2>Echo<a class="headerlink" href="#echo" title="Permalink to this headline"></a></h2>
<p>The <em>Echo</em> example demonstrates communication between two destinations using
the Packet interface.</p>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="c1">##########################################################</span>
<span class="c1"># This RNS example demonstrates a simple client/server #</span>
<span class="c1"># echo utility. A client can send an echo request to the #</span>
<span class="c1"># server, and the server will respond by proving receipt #</span>
<span class="c1"># of the packet. #</span>
<span class="c1">##########################################################</span>
<span class="kn">import</span> <span class="nn">argparse</span>
<span class="kn">import</span> <span class="nn">RNS</span>
<span class="c1"># Let&#39;s define an app name. We&#39;ll use this for all</span>
<span class="c1"># destinations we create. Since this echo example</span>
<span class="c1"># is part of a range of example utilities, we&#39;ll put</span>
<span class="c1"># them all within the app namespace &quot;example_utilities&quot;</span>
<span class="n">APP_NAME</span> <span class="o">=</span> <span class="s2">&quot;example_utilities&quot;</span>
<span class="c1">##########################################################</span>
<span class="c1">#### Server Part #########################################</span>
<span class="c1">##########################################################</span>
<span class="c1"># This initialisation is executed when the users chooses</span>
<span class="c1"># to run as a server</span>
<span class="k">def</span> <span class="nf">server</span><span class="p">(</span><span class="n">configpath</span><span class="p">):</span>
<span class="k">global</span> <span class="n">reticulum</span>
<span class="c1"># We must first initialise Reticulum</span>
<span class="n">reticulum</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Reticulum</span><span class="p">(</span><span class="n">configpath</span><span class="p">)</span>
<span class="c1"># Randomly create a new identity for our echo server</span>
<span class="n">server_identity</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Identity</span><span class="p">()</span>
<span class="c1"># We create a destination that clients can query. We want</span>
<span class="c1"># to be able to verify echo replies to our clients, so we</span>
<span class="c1"># create a &quot;single&quot; destination that can receive encrypted</span>
<span class="c1"># messages. This way the client can send a request and be</span>
<span class="c1"># certain that no-one else than this destination was able</span>
<span class="c1"># to read it. </span>
<span class="n">echo_destination</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="p">(</span>
<span class="n">server_identity</span><span class="p">,</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">IN</span><span class="p">,</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">SINGLE</span><span class="p">,</span>
<span class="n">APP_NAME</span><span class="p">,</span>
<span class="s2">&quot;echo&quot;</span><span class="p">,</span>
<span class="s2">&quot;request&quot;</span>
<span class="p">)</span>
<span class="c1"># We configure the destination to automatically prove all</span>
<span class="c1"># packets adressed to it. By doing this, RNS will automatically</span>
<span class="c1"># generate a proof for each incoming packet and transmit it</span>
<span class="c1"># back to the sender of that packet.</span>
<span class="n">echo_destination</span><span class="o">.</span><span class="n">set_proof_strategy</span><span class="p">(</span><span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">PROVE_ALL</span><span class="p">)</span>
<span class="c1"># Tell the destination which function in our program to</span>
<span class="c1"># run when a packet is received. We do this so we can</span>
<span class="c1"># print a log message when the server receives a request</span>
<span class="n">echo_destination</span><span class="o">.</span><span class="n">set_packet_callback</span><span class="p">(</span><span class="n">server_callback</span><span class="p">)</span>
<span class="c1"># Everything&#39;s ready!</span>
<span class="c1"># Let&#39;s Wait for client requests or user input</span>
<span class="n">announceLoop</span><span class="p">(</span><span class="n">echo_destination</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">announceLoop</span><span class="p">(</span><span class="n">destination</span><span class="p">):</span>
<span class="c1"># Let the user know that everything is ready</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span>
<span class="s2">&quot;Echo server &quot;</span><span class="o">+</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">prettyhexrep</span><span class="p">(</span><span class="n">destination</span><span class="o">.</span><span class="n">hash</span><span class="p">)</span><span class="o">+</span>
<span class="s2">&quot; running, hit enter to manually send an announce (Ctrl-C to quit)&quot;</span>
<span class="p">)</span>
<span class="c1"># We enter a loop that runs until the users exits.</span>
<span class="c1"># If the user hits enter, we will announce our server</span>
<span class="c1"># destination on the network, which will let clients</span>
<span class="c1"># know how to create messages directed towards it.</span>
<span class="k">while</span> <span class="kc">True</span><span class="p">:</span>
<span class="n">entered</span> <span class="o">=</span> <span class="nb">input</span><span class="p">()</span>
<span class="n">destination</span><span class="o">.</span><span class="n">announce</span><span class="p">()</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Sent announce from &quot;</span><span class="o">+</span><span class="n">RNS</span><span class="o">.</span><span class="n">prettyhexrep</span><span class="p">(</span><span class="n">destination</span><span class="o">.</span><span class="n">hash</span><span class="p">))</span>
<span class="k">def</span> <span class="nf">server_callback</span><span class="p">(</span><span class="n">message</span><span class="p">,</span> <span class="n">packet</span><span class="p">):</span>
<span class="k">global</span> <span class="n">reticulum</span>
<span class="c1"># Tell the user that we received an echo request, and</span>
<span class="c1"># that we are going to send a reply to the requester.</span>
<span class="c1"># Sending the proof is handled automatically, since we</span>
<span class="c1"># set up the destination to prove all incoming packets.</span>
<span class="n">reception_stats</span> <span class="o">=</span> <span class="s2">&quot;&quot;</span>
<span class="k">if</span> <span class="n">reticulum</span><span class="o">.</span><span class="n">is_connected_to_shared_instance</span><span class="p">:</span>
<span class="n">reception_rssi</span> <span class="o">=</span> <span class="n">reticulum</span><span class="o">.</span><span class="n">get_packet_rssi</span><span class="p">(</span><span class="n">packet</span><span class="o">.</span><span class="n">packet_hash</span><span class="p">)</span>
<span class="n">reception_snr</span> <span class="o">=</span> <span class="n">reticulum</span><span class="o">.</span><span class="n">get_packet_snr</span><span class="p">(</span><span class="n">packet</span><span class="o">.</span><span class="n">packet_hash</span><span class="p">)</span>
<span class="k">if</span> <span class="n">reception_rssi</span> <span class="o">!=</span> <span class="kc">None</span><span class="p">:</span>
<span class="n">reception_stats</span> <span class="o">+=</span> <span class="s2">&quot; [RSSI &quot;</span><span class="o">+</span><span class="nb">str</span><span class="p">(</span><span class="n">reception_rssi</span><span class="p">)</span><span class="o">+</span><span class="s2">&quot; dBm]&quot;</span>
<span class="k">if</span> <span class="n">reception_snr</span> <span class="o">!=</span> <span class="kc">None</span><span class="p">:</span>
<span class="n">reception_stats</span> <span class="o">+=</span> <span class="s2">&quot; [SNR &quot;</span><span class="o">+</span><span class="nb">str</span><span class="p">(</span><span class="n">reception_snr</span><span class="p">)</span><span class="o">+</span><span class="s2">&quot; dBm]&quot;</span>
<span class="k">else</span><span class="p">:</span>
<span class="k">if</span> <span class="n">packet</span><span class="o">.</span><span class="n">rssi</span> <span class="o">!=</span> <span class="kc">None</span><span class="p">:</span>
<span class="n">reception_stats</span> <span class="o">+=</span> <span class="s2">&quot; [RSSI &quot;</span><span class="o">+</span><span class="nb">str</span><span class="p">(</span><span class="n">packet</span><span class="o">.</span><span class="n">rssi</span><span class="p">)</span><span class="o">+</span><span class="s2">&quot; dBm]&quot;</span>
<span class="k">if</span> <span class="n">packet</span><span class="o">.</span><span class="n">snr</span> <span class="o">!=</span> <span class="kc">None</span><span class="p">:</span>
<span class="n">reception_stats</span> <span class="o">+=</span> <span class="s2">&quot; [SNR &quot;</span><span class="o">+</span><span class="nb">str</span><span class="p">(</span><span class="n">packet</span><span class="o">.</span><span class="n">snr</span><span class="p">)</span><span class="o">+</span><span class="s2">&quot; dB]&quot;</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Received packet from echo client, proof sent&quot;</span><span class="o">+</span><span class="n">reception_stats</span><span class="p">)</span>
<span class="c1">##########################################################</span>
<span class="c1">#### Client Part #########################################</span>
<span class="c1">##########################################################</span>
<span class="c1"># This initialisation is executed when the users chooses</span>
<span class="c1"># to run as a client</span>
<span class="k">def</span> <span class="nf">client</span><span class="p">(</span><span class="n">destination_hexhash</span><span class="p">,</span> <span class="n">configpath</span><span class="p">,</span> <span class="n">timeout</span><span class="o">=</span><span class="kc">None</span><span class="p">):</span>
<span class="k">global</span> <span class="n">reticulum</span>
<span class="c1"># We need a binary representation of the destination</span>
<span class="c1"># hash that was entered on the command line</span>
<span class="k">try</span><span class="p">:</span>
<span class="k">if</span> <span class="nb">len</span><span class="p">(</span><span class="n">destination_hexhash</span><span class="p">)</span> <span class="o">!=</span> <span class="mi">20</span><span class="p">:</span>
<span class="k">raise</span> <span class="ne">ValueError</span><span class="p">(</span>
<span class="s2">&quot;Destination length is invalid, must be 20 hexadecimal characters (10 bytes)&quot;</span>
<span class="p">)</span>
<span class="n">destination_hash</span> <span class="o">=</span> <span class="nb">bytes</span><span class="o">.</span><span class="n">fromhex</span><span class="p">(</span><span class="n">destination_hexhash</span><span class="p">)</span>
<span class="k">except</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Invalid destination entered. Check your input!</span><span class="se">\n</span><span class="s2">&quot;</span><span class="p">)</span>
<span class="n">exit</span><span class="p">()</span>
<span class="c1"># We must first initialise Reticulum</span>
<span class="n">reticulum</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Reticulum</span><span class="p">(</span><span class="n">configpath</span><span class="p">)</span>
<span class="c1"># We override the loglevel to provide feedback when</span>
<span class="c1"># an announce is received</span>
<span class="k">if</span> <span class="n">RNS</span><span class="o">.</span><span class="n">loglevel</span> <span class="o">&lt;</span> <span class="n">RNS</span><span class="o">.</span><span class="n">LOG_INFO</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">loglevel</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">LOG_INFO</span>
<span class="c1"># Tell the user that the client is ready!</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span>
<span class="s2">&quot;Echo client ready, hit enter to send echo request to &quot;</span><span class="o">+</span>
<span class="n">destination_hexhash</span><span class="o">+</span>
<span class="s2">&quot; (Ctrl-C to quit)&quot;</span>
<span class="p">)</span>
<span class="c1"># We enter a loop that runs until the user exits.</span>
<span class="c1"># If the user hits enter, we will try to send an</span>
<span class="c1"># echo request to the destination specified on the</span>
<span class="c1"># command line.</span>
<span class="k">while</span> <span class="kc">True</span><span class="p">:</span>
<span class="nb">input</span><span class="p">()</span>
<span class="c1"># Let&#39;s first check if RNS knows a path to the destination.</span>
<span class="c1"># If it does, we&#39;ll load the server identity and create a packet</span>
<span class="k">if</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Transport</span><span class="o">.</span><span class="n">has_path</span><span class="p">(</span><span class="n">destination_hash</span><span class="p">):</span>
<span class="c1"># To address the server, we need to know it&#39;s public</span>
<span class="c1"># key, so we check if Reticulum knows this destination.</span>
<span class="c1"># This is done by calling the &quot;recall&quot; method of the</span>
<span class="c1"># Identity module. If the destination is known, it will</span>
<span class="c1"># return an Identity instance that can be used in</span>
<span class="c1"># outgoing destinations.</span>
<span class="n">server_identity</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Identity</span><span class="o">.</span><span class="n">recall</span><span class="p">(</span><span class="n">destination_hash</span><span class="p">)</span>
<span class="c1"># We got the correct identity instance from the</span>
<span class="c1"># recall method, so let&#39;s create an outgoing</span>
<span class="c1"># destination. We use the naming convention:</span>
<span class="c1"># example_utilities.echo.request</span>
<span class="c1"># This matches the naming we specified in the</span>
<span class="c1"># server part of the code.</span>
<span class="n">request_destination</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="p">(</span>
<span class="n">server_identity</span><span class="p">,</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">OUT</span><span class="p">,</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">SINGLE</span><span class="p">,</span>
<span class="n">APP_NAME</span><span class="p">,</span>
<span class="s2">&quot;echo&quot;</span><span class="p">,</span>
<span class="s2">&quot;request&quot;</span>
<span class="p">)</span>
<span class="c1"># The destination is ready, so let&#39;s create a packet.</span>
<span class="c1"># We set the destination to the request_destination</span>
<span class="c1"># that was just created, and the only data we add</span>
<span class="c1"># is a random hash.</span>
<span class="n">echo_request</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Packet</span><span class="p">(</span><span class="n">request_destination</span><span class="p">,</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Identity</span><span class="o">.</span><span class="n">get_random_hash</span><span class="p">())</span>
<span class="c1"># Send the packet! If the packet is successfully</span>
<span class="c1"># sent, it will return a PacketReceipt instance.</span>
<span class="n">packet_receipt</span> <span class="o">=</span> <span class="n">echo_request</span><span class="o">.</span><span class="n">send</span><span class="p">()</span>
<span class="c1"># If the user specified a timeout, we set this</span>
<span class="c1"># timeout on the packet receipt, and configure</span>
<span class="c1"># a callback function, that will get called if</span>
<span class="c1"># the packet times out.</span>
<span class="k">if</span> <span class="n">timeout</span> <span class="o">!=</span> <span class="kc">None</span><span class="p">:</span>
<span class="n">packet_receipt</span><span class="o">.</span><span class="n">set_timeout</span><span class="p">(</span><span class="n">timeout</span><span class="p">)</span>
<span class="n">packet_receipt</span><span class="o">.</span><span class="n">set_timeout_callback</span><span class="p">(</span><span class="n">packet_timed_out</span><span class="p">)</span>
<span class="c1"># We can then set a delivery callback on the receipt.</span>
<span class="c1"># This will get automatically called when a proof for</span>
<span class="c1"># this specific packet is received from the destination.</span>
<span class="n">packet_receipt</span><span class="o">.</span><span class="n">set_delivery_callback</span><span class="p">(</span><span class="n">packet_delivered</span><span class="p">)</span>
<span class="c1"># Tell the user that the echo request was sent</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Sent echo request to &quot;</span><span class="o">+</span><span class="n">RNS</span><span class="o">.</span><span class="n">prettyhexrep</span><span class="p">(</span><span class="n">request_destination</span><span class="o">.</span><span class="n">hash</span><span class="p">))</span>
<span class="k">else</span><span class="p">:</span>
<span class="c1"># If we do not know this destination, tell the</span>
<span class="c1"># user to wait for an announce to arrive.</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Destination is not yet known. Requesting path...&quot;</span><span class="p">)</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Transport</span><span class="o">.</span><span class="n">request_path</span><span class="p">(</span><span class="n">destination_hash</span><span class="p">)</span>
<span class="c1"># This function is called when our reply destination</span>
<span class="c1"># receives a proof packet.</span>
<span class="k">def</span> <span class="nf">packet_delivered</span><span class="p">(</span><span class="n">receipt</span><span class="p">):</span>
<span class="k">global</span> <span class="n">reticulum</span>
<span class="k">if</span> <span class="n">receipt</span><span class="o">.</span><span class="n">status</span> <span class="o">==</span> <span class="n">RNS</span><span class="o">.</span><span class="n">PacketReceipt</span><span class="o">.</span><span class="n">DELIVERED</span><span class="p">:</span>
<span class="n">rtt</span> <span class="o">=</span> <span class="n">receipt</span><span class="o">.</span><span class="n">get_rtt</span><span class="p">()</span>
<span class="k">if</span> <span class="p">(</span><span class="n">rtt</span> <span class="o">&gt;=</span> <span class="mi">1</span><span class="p">):</span>
<span class="n">rtt</span> <span class="o">=</span> <span class="nb">round</span><span class="p">(</span><span class="n">rtt</span><span class="p">,</span> <span class="mi">3</span><span class="p">)</span>
<span class="n">rttstring</span> <span class="o">=</span> <span class="nb">str</span><span class="p">(</span><span class="n">rtt</span><span class="p">)</span><span class="o">+</span><span class="s2">&quot; seconds&quot;</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">rtt</span> <span class="o">=</span> <span class="nb">round</span><span class="p">(</span><span class="n">rtt</span><span class="o">*</span><span class="mi">1000</span><span class="p">,</span> <span class="mi">3</span><span class="p">)</span>
<span class="n">rttstring</span> <span class="o">=</span> <span class="nb">str</span><span class="p">(</span><span class="n">rtt</span><span class="p">)</span><span class="o">+</span><span class="s2">&quot; milliseconds&quot;</span>
<span class="n">reception_stats</span> <span class="o">=</span> <span class="s2">&quot;&quot;</span>
<span class="k">if</span> <span class="n">reticulum</span><span class="o">.</span><span class="n">is_connected_to_shared_instance</span><span class="p">:</span>
<span class="n">reception_rssi</span> <span class="o">=</span> <span class="n">reticulum</span><span class="o">.</span><span class="n">get_packet_rssi</span><span class="p">(</span><span class="n">receipt</span><span class="o">.</span><span class="n">proof_packet</span><span class="o">.</span><span class="n">packet_hash</span><span class="p">)</span>
<span class="n">reception_snr</span> <span class="o">=</span> <span class="n">reticulum</span><span class="o">.</span><span class="n">get_packet_snr</span><span class="p">(</span><span class="n">receipt</span><span class="o">.</span><span class="n">proof_packet</span><span class="o">.</span><span class="n">packet_hash</span><span class="p">)</span>
<span class="k">if</span> <span class="n">reception_rssi</span> <span class="o">!=</span> <span class="kc">None</span><span class="p">:</span>
<span class="n">reception_stats</span> <span class="o">+=</span> <span class="s2">&quot; [RSSI &quot;</span><span class="o">+</span><span class="nb">str</span><span class="p">(</span><span class="n">reception_rssi</span><span class="p">)</span><span class="o">+</span><span class="s2">&quot; dBm]&quot;</span>
<span class="k">if</span> <span class="n">reception_snr</span> <span class="o">!=</span> <span class="kc">None</span><span class="p">:</span>
<span class="n">reception_stats</span> <span class="o">+=</span> <span class="s2">&quot; [SNR &quot;</span><span class="o">+</span><span class="nb">str</span><span class="p">(</span><span class="n">reception_snr</span><span class="p">)</span><span class="o">+</span><span class="s2">&quot; dB]&quot;</span>
<span class="k">else</span><span class="p">:</span>
<span class="k">if</span> <span class="n">receipt</span><span class="o">.</span><span class="n">proof_packet</span> <span class="o">!=</span> <span class="kc">None</span><span class="p">:</span>
<span class="k">if</span> <span class="n">receipt</span><span class="o">.</span><span class="n">proof_packet</span><span class="o">.</span><span class="n">rssi</span> <span class="o">!=</span> <span class="kc">None</span><span class="p">:</span>
<span class="n">reception_stats</span> <span class="o">+=</span> <span class="s2">&quot; [RSSI &quot;</span><span class="o">+</span><span class="nb">str</span><span class="p">(</span><span class="n">receipt</span><span class="o">.</span><span class="n">proof_packet</span><span class="o">.</span><span class="n">rssi</span><span class="p">)</span><span class="o">+</span><span class="s2">&quot; dBm]&quot;</span>
<span class="k">if</span> <span class="n">receipt</span><span class="o">.</span><span class="n">proof_packet</span><span class="o">.</span><span class="n">snr</span> <span class="o">!=</span> <span class="kc">None</span><span class="p">:</span>
<span class="n">reception_stats</span> <span class="o">+=</span> <span class="s2">&quot; [SNR &quot;</span><span class="o">+</span><span class="nb">str</span><span class="p">(</span><span class="n">receipt</span><span class="o">.</span><span class="n">proof_packet</span><span class="o">.</span><span class="n">snr</span><span class="p">)</span><span class="o">+</span><span class="s2">&quot; dB]&quot;</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span>
<span class="s2">&quot;Valid reply received from &quot;</span><span class="o">+</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">prettyhexrep</span><span class="p">(</span><span class="n">receipt</span><span class="o">.</span><span class="n">destination</span><span class="o">.</span><span class="n">hash</span><span class="p">)</span><span class="o">+</span>
<span class="s2">&quot;, round-trip time is &quot;</span><span class="o">+</span><span class="n">rttstring</span><span class="o">+</span>
<span class="n">reception_stats</span>
<span class="p">)</span>
<span class="c1"># This function is called if a packet times out.</span>
<span class="k">def</span> <span class="nf">packet_timed_out</span><span class="p">(</span><span class="n">receipt</span><span class="p">):</span>
<span class="k">if</span> <span class="n">receipt</span><span class="o">.</span><span class="n">status</span> <span class="o">==</span> <span class="n">RNS</span><span class="o">.</span><span class="n">PacketReceipt</span><span class="o">.</span><span class="n">FAILED</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Packet &quot;</span><span class="o">+</span><span class="n">RNS</span><span class="o">.</span><span class="n">prettyhexrep</span><span class="p">(</span><span class="n">receipt</span><span class="o">.</span><span class="n">hash</span><span class="p">)</span><span class="o">+</span><span class="s2">&quot; timed out&quot;</span><span class="p">)</span>
<span class="c1">##########################################################</span>
<span class="c1">#### Program Startup #####################################</span>
<span class="c1">##########################################################</span>
<span class="c1"># This part of the program gets run at startup,</span>
<span class="c1"># and parses input from the user, and then starts</span>
<span class="c1"># the desired program mode.</span>
<span class="k">if</span> <span class="vm">__name__</span> <span class="o">==</span> <span class="s2">&quot;__main__&quot;</span><span class="p">:</span>
<span class="k">try</span><span class="p">:</span>
<span class="n">parser</span> <span class="o">=</span> <span class="n">argparse</span><span class="o">.</span><span class="n">ArgumentParser</span><span class="p">(</span><span class="n">description</span><span class="o">=</span><span class="s2">&quot;Simple echo server and client utility&quot;</span><span class="p">)</span>
<span class="n">parser</span><span class="o">.</span><span class="n">add_argument</span><span class="p">(</span>
<span class="s2">&quot;-s&quot;</span><span class="p">,</span>
<span class="s2">&quot;--server&quot;</span><span class="p">,</span>
<span class="n">action</span><span class="o">=</span><span class="s2">&quot;store_true&quot;</span><span class="p">,</span>
<span class="n">help</span><span class="o">=</span><span class="s2">&quot;wait for incoming packets from clients&quot;</span>
<span class="p">)</span>
<span class="n">parser</span><span class="o">.</span><span class="n">add_argument</span><span class="p">(</span>
<span class="s2">&quot;-t&quot;</span><span class="p">,</span>
<span class="s2">&quot;--timeout&quot;</span><span class="p">,</span>
<span class="n">action</span><span class="o">=</span><span class="s2">&quot;store&quot;</span><span class="p">,</span>
<span class="n">metavar</span><span class="o">=</span><span class="s2">&quot;s&quot;</span><span class="p">,</span>
<span class="n">default</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span>
<span class="n">help</span><span class="o">=</span><span class="s2">&quot;set a reply timeout in seconds&quot;</span><span class="p">,</span>
<span class="nb">type</span><span class="o">=</span><span class="nb">float</span>
<span class="p">)</span>
<span class="n">parser</span><span class="o">.</span><span class="n">add_argument</span><span class="p">(</span><span class="s2">&quot;--config&quot;</span><span class="p">,</span>
<span class="n">action</span><span class="o">=</span><span class="s2">&quot;store&quot;</span><span class="p">,</span>
<span class="n">default</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span>
<span class="n">help</span><span class="o">=</span><span class="s2">&quot;path to alternative Reticulum config directory&quot;</span><span class="p">,</span>
<span class="nb">type</span><span class="o">=</span><span class="nb">str</span>
<span class="p">)</span>
<span class="n">parser</span><span class="o">.</span><span class="n">add_argument</span><span class="p">(</span>
<span class="s2">&quot;destination&quot;</span><span class="p">,</span>
<span class="n">nargs</span><span class="o">=</span><span class="s2">&quot;?&quot;</span><span class="p">,</span>
<span class="n">default</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span>
<span class="n">help</span><span class="o">=</span><span class="s2">&quot;hexadecimal hash of the server destination&quot;</span><span class="p">,</span>
<span class="nb">type</span><span class="o">=</span><span class="nb">str</span>
<span class="p">)</span>
<span class="n">args</span> <span class="o">=</span> <span class="n">parser</span><span class="o">.</span><span class="n">parse_args</span><span class="p">()</span>
<span class="k">if</span> <span class="n">args</span><span class="o">.</span><span class="n">server</span><span class="p">:</span>
<span class="n">configarg</span><span class="o">=</span><span class="kc">None</span>
<span class="k">if</span> <span class="n">args</span><span class="o">.</span><span class="n">config</span><span class="p">:</span>
<span class="n">configarg</span> <span class="o">=</span> <span class="n">args</span><span class="o">.</span><span class="n">config</span>
<span class="n">server</span><span class="p">(</span><span class="n">configarg</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="k">if</span> <span class="n">args</span><span class="o">.</span><span class="n">config</span><span class="p">:</span>
<span class="n">configarg</span> <span class="o">=</span> <span class="n">args</span><span class="o">.</span><span class="n">config</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">configarg</span> <span class="o">=</span> <span class="kc">None</span>
<span class="k">if</span> <span class="n">args</span><span class="o">.</span><span class="n">timeout</span><span class="p">:</span>
<span class="n">timeoutarg</span> <span class="o">=</span> <span class="nb">float</span><span class="p">(</span><span class="n">args</span><span class="o">.</span><span class="n">timeout</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">timeoutarg</span> <span class="o">=</span> <span class="kc">None</span>
<span class="k">if</span> <span class="p">(</span><span class="n">args</span><span class="o">.</span><span class="n">destination</span> <span class="o">==</span> <span class="kc">None</span><span class="p">):</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="n">parser</span><span class="o">.</span><span class="n">print_help</span><span class="p">()</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">client</span><span class="p">(</span><span class="n">args</span><span class="o">.</span><span class="n">destination</span><span class="p">,</span> <span class="n">configarg</span><span class="p">,</span> <span class="n">timeout</span><span class="o">=</span><span class="n">timeoutarg</span><span class="p">)</span>
<span class="k">except</span> <span class="ne">KeyboardInterrupt</span><span class="p">:</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="n">exit</span><span class="p">()</span>
</pre></div>
</div>
<p>This example can also be found at <a class="reference external" href="https://github.com/markqvist/Reticulum/blob/master/Examples/Echo.py">https://github.com/markqvist/Reticulum/blob/master/Examples/Echo.py</a>.</p>
</div>
<div class="section" id="link">
<span id="example-link"></span><h2>Link<a class="headerlink" href="#link" title="Permalink to this headline"></a></h2>
<p>The <em>Link</em> example explores establishing an encrypted link to a remote
destination, and passing traffic back and forth over the link.</p>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="c1">##########################################################</span>
<span class="c1"># This RNS example demonstrates how to set up a link to #</span>
<span class="c1"># a destination, and pass data back and forth over it. #</span>
<span class="c1">##########################################################</span>
<span class="kn">import</span> <span class="nn">os</span>
<span class="kn">import</span> <span class="nn">sys</span>
<span class="kn">import</span> <span class="nn">time</span>
<span class="kn">import</span> <span class="nn">argparse</span>
<span class="kn">import</span> <span class="nn">RNS</span>
<span class="c1"># Let&#39;s define an app name. We&#39;ll use this for all</span>
<span class="c1"># destinations we create. Since this echo example</span>
<span class="c1"># is part of a range of example utilities, we&#39;ll put</span>
<span class="c1"># them all within the app namespace &quot;example_utilities&quot;</span>
<span class="n">APP_NAME</span> <span class="o">=</span> <span class="s2">&quot;example_utilities&quot;</span>
<span class="c1">##########################################################</span>
<span class="c1">#### Server Part #########################################</span>
<span class="c1">##########################################################</span>
<span class="c1"># A reference to the latest client link that connected</span>
<span class="n">latest_client_link</span> <span class="o">=</span> <span class="kc">None</span>
<span class="c1"># This initialisation is executed when the users chooses</span>
<span class="c1"># to run as a server</span>
<span class="k">def</span> <span class="nf">server</span><span class="p">(</span><span class="n">configpath</span><span class="p">):</span>
<span class="c1"># We must first initialise Reticulum</span>
<span class="n">reticulum</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Reticulum</span><span class="p">(</span><span class="n">configpath</span><span class="p">)</span>
<span class="c1"># Randomly create a new identity for our link example</span>
<span class="n">server_identity</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Identity</span><span class="p">()</span>
<span class="c1"># We create a destination that clients can connect to. We</span>
<span class="c1"># want clients to create links to this destination, so we</span>
<span class="c1"># need to create a &quot;single&quot; destination type.</span>
<span class="n">server_destination</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="p">(</span>
<span class="n">server_identity</span><span class="p">,</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">IN</span><span class="p">,</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">SINGLE</span><span class="p">,</span>
<span class="n">APP_NAME</span><span class="p">,</span>
<span class="s2">&quot;linkexample&quot;</span>
<span class="p">)</span>
<span class="c1"># We configure a function that will get called every time</span>
<span class="c1"># a new client creates a link to this destination.</span>
<span class="n">server_destination</span><span class="o">.</span><span class="n">set_link_established_callback</span><span class="p">(</span><span class="n">client_connected</span><span class="p">)</span>
<span class="c1"># Everything&#39;s ready!</span>
<span class="c1"># Let&#39;s Wait for client requests or user input</span>
<span class="n">server_loop</span><span class="p">(</span><span class="n">server_destination</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">server_loop</span><span class="p">(</span><span class="n">destination</span><span class="p">):</span>
<span class="c1"># Let the user know that everything is ready</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span>
<span class="s2">&quot;Link example &quot;</span><span class="o">+</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">prettyhexrep</span><span class="p">(</span><span class="n">destination</span><span class="o">.</span><span class="n">hash</span><span class="p">)</span><span class="o">+</span>
<span class="s2">&quot; running, waiting for a connection.&quot;</span>
<span class="p">)</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Hit enter to manually send an announce (Ctrl-C to quit)&quot;</span><span class="p">)</span>
<span class="c1"># We enter a loop that runs until the users exits.</span>
<span class="c1"># If the user hits enter, we will announce our server</span>
<span class="c1"># destination on the network, which will let clients</span>
<span class="c1"># know how to create messages directed towards it.</span>
<span class="k">while</span> <span class="kc">True</span><span class="p">:</span>
<span class="n">entered</span> <span class="o">=</span> <span class="nb">input</span><span class="p">()</span>
<span class="n">destination</span><span class="o">.</span><span class="n">announce</span><span class="p">()</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Sent announce from &quot;</span><span class="o">+</span><span class="n">RNS</span><span class="o">.</span><span class="n">prettyhexrep</span><span class="p">(</span><span class="n">destination</span><span class="o">.</span><span class="n">hash</span><span class="p">))</span>
<span class="c1"># When a client establishes a link to our server</span>
<span class="c1"># destination, this function will be called with</span>
<span class="c1"># a reference to the link.</span>
<span class="k">def</span> <span class="nf">client_connected</span><span class="p">(</span><span class="n">link</span><span class="p">):</span>
<span class="k">global</span> <span class="n">latest_client_link</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Client connected&quot;</span><span class="p">)</span>
<span class="n">link</span><span class="o">.</span><span class="n">set_link_closed_callback</span><span class="p">(</span><span class="n">client_disconnected</span><span class="p">)</span>
<span class="n">link</span><span class="o">.</span><span class="n">set_packet_callback</span><span class="p">(</span><span class="n">server_packet_received</span><span class="p">)</span>
<span class="n">latest_client_link</span> <span class="o">=</span> <span class="n">link</span>
<span class="k">def</span> <span class="nf">client_disconnected</span><span class="p">(</span><span class="n">link</span><span class="p">):</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Client disconnected&quot;</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">server_packet_received</span><span class="p">(</span><span class="n">message</span><span class="p">,</span> <span class="n">packet</span><span class="p">):</span>
<span class="k">global</span> <span class="n">latest_client_link</span>
<span class="c1"># When data is received over any active link,</span>
<span class="c1"># it will all be directed to the last client</span>
<span class="c1"># that connected.</span>
<span class="n">text</span> <span class="o">=</span> <span class="n">message</span><span class="o">.</span><span class="n">decode</span><span class="p">(</span><span class="s2">&quot;utf-8&quot;</span><span class="p">)</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Received data on the link: &quot;</span><span class="o">+</span><span class="n">text</span><span class="p">)</span>
<span class="n">reply_text</span> <span class="o">=</span> <span class="s2">&quot;I received </span><span class="se">\&quot;</span><span class="s2">&quot;</span><span class="o">+</span><span class="n">text</span><span class="o">+</span><span class="s2">&quot;</span><span class="se">\&quot;</span><span class="s2"> over the link&quot;</span>
<span class="n">reply_data</span> <span class="o">=</span> <span class="n">reply_text</span><span class="o">.</span><span class="n">encode</span><span class="p">(</span><span class="s2">&quot;utf-8&quot;</span><span class="p">)</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Packet</span><span class="p">(</span><span class="n">latest_client_link</span><span class="p">,</span> <span class="n">reply_data</span><span class="p">)</span><span class="o">.</span><span class="n">send</span><span class="p">()</span>
<span class="c1">##########################################################</span>
<span class="c1">#### Client Part #########################################</span>
<span class="c1">##########################################################</span>
<span class="c1"># A reference to the server link</span>
<span class="n">server_link</span> <span class="o">=</span> <span class="kc">None</span>
<span class="c1"># This initialisation is executed when the users chooses</span>
<span class="c1"># to run as a client</span>
<span class="k">def</span> <span class="nf">client</span><span class="p">(</span><span class="n">destination_hexhash</span><span class="p">,</span> <span class="n">configpath</span><span class="p">):</span>
<span class="c1"># We need a binary representation of the destination</span>
<span class="c1"># hash that was entered on the command line</span>
<span class="k">try</span><span class="p">:</span>
<span class="k">if</span> <span class="nb">len</span><span class="p">(</span><span class="n">destination_hexhash</span><span class="p">)</span> <span class="o">!=</span> <span class="mi">20</span><span class="p">:</span>
<span class="k">raise</span> <span class="ne">ValueError</span><span class="p">(</span><span class="s2">&quot;Destination length is invalid, must be 20 hexadecimal characters (10 bytes)&quot;</span><span class="p">)</span>
<span class="n">destination_hash</span> <span class="o">=</span> <span class="nb">bytes</span><span class="o">.</span><span class="n">fromhex</span><span class="p">(</span><span class="n">destination_hexhash</span><span class="p">)</span>
<span class="k">except</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Invalid destination entered. Check your input!</span><span class="se">\n</span><span class="s2">&quot;</span><span class="p">)</span>
<span class="n">exit</span><span class="p">()</span>
<span class="c1"># We must first initialise Reticulum</span>
<span class="n">reticulum</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Reticulum</span><span class="p">(</span><span class="n">configpath</span><span class="p">)</span>
<span class="c1"># Check if we know a path to the destination</span>
<span class="k">if</span> <span class="ow">not</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Transport</span><span class="o">.</span><span class="n">has_path</span><span class="p">(</span><span class="n">destination_hash</span><span class="p">):</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Destination is not yet known. Requesting path and waiting for announce to arrive...&quot;</span><span class="p">)</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Transport</span><span class="o">.</span><span class="n">request_path</span><span class="p">(</span><span class="n">destination_hash</span><span class="p">)</span>
<span class="k">while</span> <span class="ow">not</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Transport</span><span class="o">.</span><span class="n">has_path</span><span class="p">(</span><span class="n">destination_hash</span><span class="p">):</span>
<span class="n">time</span><span class="o">.</span><span class="n">sleep</span><span class="p">(</span><span class="mf">0.1</span><span class="p">)</span>
<span class="c1"># Recall the server identity</span>
<span class="n">server_identity</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Identity</span><span class="o">.</span><span class="n">recall</span><span class="p">(</span><span class="n">destination_hash</span><span class="p">)</span>
<span class="c1"># Inform the user that we&#39;ll begin connecting</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Establishing link with server...&quot;</span><span class="p">)</span>
<span class="c1"># When the server identity is known, we set</span>
<span class="c1"># up a destination</span>
<span class="n">server_destination</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="p">(</span>
<span class="n">server_identity</span><span class="p">,</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">OUT</span><span class="p">,</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">SINGLE</span><span class="p">,</span>
<span class="n">APP_NAME</span><span class="p">,</span>
<span class="s2">&quot;linkexample&quot;</span>
<span class="p">)</span>
<span class="c1"># And create a link</span>
<span class="n">link</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Link</span><span class="p">(</span><span class="n">server_destination</span><span class="p">)</span>
<span class="c1"># We set a callback that will get executed</span>
<span class="c1"># every time a packet is received over the</span>
<span class="c1"># link</span>
<span class="n">link</span><span class="o">.</span><span class="n">set_packet_callback</span><span class="p">(</span><span class="n">client_packet_received</span><span class="p">)</span>
<span class="c1"># We&#39;ll also set up functions to inform the</span>
<span class="c1"># user when the link is established or closed</span>
<span class="n">link</span><span class="o">.</span><span class="n">set_link_established_callback</span><span class="p">(</span><span class="n">link_established</span><span class="p">)</span>
<span class="n">link</span><span class="o">.</span><span class="n">set_link_closed_callback</span><span class="p">(</span><span class="n">link_closed</span><span class="p">)</span>
<span class="c1"># Everything is set up, so let&#39;s enter a loop</span>
<span class="c1"># for the user to interact with the example</span>
<span class="n">client_loop</span><span class="p">()</span>
<span class="k">def</span> <span class="nf">client_loop</span><span class="p">():</span>
<span class="k">global</span> <span class="n">server_link</span>
<span class="c1"># Wait for the link to become active</span>
<span class="k">while</span> <span class="ow">not</span> <span class="n">server_link</span><span class="p">:</span>
<span class="n">time</span><span class="o">.</span><span class="n">sleep</span><span class="p">(</span><span class="mf">0.1</span><span class="p">)</span>
<span class="n">should_quit</span> <span class="o">=</span> <span class="kc">False</span>
<span class="k">while</span> <span class="ow">not</span> <span class="n">should_quit</span><span class="p">:</span>
<span class="k">try</span><span class="p">:</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&gt; &quot;</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="s2">&quot; &quot;</span><span class="p">)</span>
<span class="n">text</span> <span class="o">=</span> <span class="nb">input</span><span class="p">()</span>
<span class="c1"># Check if we should quit the example</span>
<span class="k">if</span> <span class="n">text</span> <span class="o">==</span> <span class="s2">&quot;quit&quot;</span> <span class="ow">or</span> <span class="n">text</span> <span class="o">==</span> <span class="s2">&quot;q&quot;</span> <span class="ow">or</span> <span class="n">text</span> <span class="o">==</span> <span class="s2">&quot;exit&quot;</span><span class="p">:</span>
<span class="n">should_quit</span> <span class="o">=</span> <span class="kc">True</span>
<span class="n">server_link</span><span class="o">.</span><span class="n">teardown</span><span class="p">()</span>
<span class="c1"># If not, send the entered text over the link</span>
<span class="k">if</span> <span class="n">text</span> <span class="o">!=</span> <span class="s2">&quot;&quot;</span><span class="p">:</span>
<span class="n">data</span> <span class="o">=</span> <span class="n">text</span><span class="o">.</span><span class="n">encode</span><span class="p">(</span><span class="s2">&quot;utf-8&quot;</span><span class="p">)</span>
<span class="k">if</span> <span class="nb">len</span><span class="p">(</span><span class="n">data</span><span class="p">)</span> <span class="o">&lt;=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Link</span><span class="o">.</span><span class="n">MDU</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Packet</span><span class="p">(</span><span class="n">server_link</span><span class="p">,</span> <span class="n">data</span><span class="p">)</span><span class="o">.</span><span class="n">send</span><span class="p">()</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span>
<span class="s2">&quot;Cannot send this packet, the data size of &quot;</span><span class="o">+</span>
<span class="nb">str</span><span class="p">(</span><span class="nb">len</span><span class="p">(</span><span class="n">data</span><span class="p">))</span><span class="o">+</span><span class="s2">&quot; bytes exceeds the link packet MDU of &quot;</span><span class="o">+</span>
<span class="nb">str</span><span class="p">(</span><span class="n">RNS</span><span class="o">.</span><span class="n">Link</span><span class="o">.</span><span class="n">MDU</span><span class="p">)</span><span class="o">+</span><span class="s2">&quot; bytes&quot;</span><span class="p">,</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">LOG_ERROR</span>
<span class="p">)</span>
<span class="k">except</span> <span class="ne">Exception</span> <span class="k">as</span> <span class="n">e</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Error while sending data over the link: &quot;</span><span class="o">+</span><span class="nb">str</span><span class="p">(</span><span class="n">e</span><span class="p">))</span>
<span class="n">should_quit</span> <span class="o">=</span> <span class="kc">True</span>
<span class="n">server_link</span><span class="o">.</span><span class="n">teardown</span><span class="p">()</span>
<span class="c1"># This function is called when a link</span>
<span class="c1"># has been established with the server</span>
<span class="k">def</span> <span class="nf">link_established</span><span class="p">(</span><span class="n">link</span><span class="p">):</span>
<span class="c1"># We store a reference to the link</span>
<span class="c1"># instance for later use</span>
<span class="k">global</span> <span class="n">server_link</span>
<span class="n">server_link</span> <span class="o">=</span> <span class="n">link</span>
<span class="c1"># Inform the user that the server is</span>
<span class="c1"># connected</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Link established with server, enter some text to send, or </span><span class="se">\&quot;</span><span class="s2">quit</span><span class="se">\&quot;</span><span class="s2"> to quit&quot;</span><span class="p">)</span>
<span class="c1"># When a link is closed, we&#39;ll inform the</span>
<span class="c1"># user, and exit the program</span>
<span class="k">def</span> <span class="nf">link_closed</span><span class="p">(</span><span class="n">link</span><span class="p">):</span>
<span class="k">if</span> <span class="n">link</span><span class="o">.</span><span class="n">teardown_reason</span> <span class="o">==</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Link</span><span class="o">.</span><span class="n">TIMEOUT</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;The link timed out, exiting now&quot;</span><span class="p">)</span>
<span class="k">elif</span> <span class="n">link</span><span class="o">.</span><span class="n">teardown_reason</span> <span class="o">==</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Link</span><span class="o">.</span><span class="n">DESTINATION_CLOSED</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;The link was closed by the server, exiting now&quot;</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Link closed, exiting now&quot;</span><span class="p">)</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Reticulum</span><span class="o">.</span><span class="n">exit_handler</span><span class="p">()</span>
<span class="n">time</span><span class="o">.</span><span class="n">sleep</span><span class="p">(</span><span class="mf">1.5</span><span class="p">)</span>
<span class="n">os</span><span class="o">.</span><span class="n">_exit</span><span class="p">(</span><span class="mi">0</span><span class="p">)</span>
<span class="c1"># When a packet is received over the link, we</span>
<span class="c1"># simply print out the data.</span>
<span class="k">def</span> <span class="nf">client_packet_received</span><span class="p">(</span><span class="n">message</span><span class="p">,</span> <span class="n">packet</span><span class="p">):</span>
<span class="n">text</span> <span class="o">=</span> <span class="n">message</span><span class="o">.</span><span class="n">decode</span><span class="p">(</span><span class="s2">&quot;utf-8&quot;</span><span class="p">)</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Received data on the link: &quot;</span><span class="o">+</span><span class="n">text</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&gt; &quot;</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="s2">&quot; &quot;</span><span class="p">)</span>
<span class="n">sys</span><span class="o">.</span><span class="n">stdout</span><span class="o">.</span><span class="n">flush</span><span class="p">()</span>
<span class="c1">##########################################################</span>
<span class="c1">#### Program Startup #####################################</span>
<span class="c1">##########################################################</span>
<span class="c1"># This part of the program runs at startup,</span>
<span class="c1"># and parses input of from the user, and then</span>
<span class="c1"># starts up the desired program mode.</span>
<span class="k">if</span> <span class="vm">__name__</span> <span class="o">==</span> <span class="s2">&quot;__main__&quot;</span><span class="p">:</span>
<span class="k">try</span><span class="p">:</span>
<span class="n">parser</span> <span class="o">=</span> <span class="n">argparse</span><span class="o">.</span><span class="n">ArgumentParser</span><span class="p">(</span><span class="n">description</span><span class="o">=</span><span class="s2">&quot;Simple link example&quot;</span><span class="p">)</span>
<span class="n">parser</span><span class="o">.</span><span class="n">add_argument</span><span class="p">(</span>
<span class="s2">&quot;-s&quot;</span><span class="p">,</span>
<span class="s2">&quot;--server&quot;</span><span class="p">,</span>
<span class="n">action</span><span class="o">=</span><span class="s2">&quot;store_true&quot;</span><span class="p">,</span>
<span class="n">help</span><span class="o">=</span><span class="s2">&quot;wait for incoming link requests from clients&quot;</span>
<span class="p">)</span>
<span class="n">parser</span><span class="o">.</span><span class="n">add_argument</span><span class="p">(</span>
<span class="s2">&quot;--config&quot;</span><span class="p">,</span>
<span class="n">action</span><span class="o">=</span><span class="s2">&quot;store&quot;</span><span class="p">,</span>
<span class="n">default</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span>
<span class="n">help</span><span class="o">=</span><span class="s2">&quot;path to alternative Reticulum config directory&quot;</span><span class="p">,</span>
<span class="nb">type</span><span class="o">=</span><span class="nb">str</span>
<span class="p">)</span>
<span class="n">parser</span><span class="o">.</span><span class="n">add_argument</span><span class="p">(</span>
<span class="s2">&quot;destination&quot;</span><span class="p">,</span>
<span class="n">nargs</span><span class="o">=</span><span class="s2">&quot;?&quot;</span><span class="p">,</span>
<span class="n">default</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span>
<span class="n">help</span><span class="o">=</span><span class="s2">&quot;hexadecimal hash of the server destination&quot;</span><span class="p">,</span>
<span class="nb">type</span><span class="o">=</span><span class="nb">str</span>
<span class="p">)</span>
<span class="n">args</span> <span class="o">=</span> <span class="n">parser</span><span class="o">.</span><span class="n">parse_args</span><span class="p">()</span>
<span class="k">if</span> <span class="n">args</span><span class="o">.</span><span class="n">config</span><span class="p">:</span>
<span class="n">configarg</span> <span class="o">=</span> <span class="n">args</span><span class="o">.</span><span class="n">config</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">configarg</span> <span class="o">=</span> <span class="kc">None</span>
<span class="k">if</span> <span class="n">args</span><span class="o">.</span><span class="n">server</span><span class="p">:</span>
<span class="n">server</span><span class="p">(</span><span class="n">configarg</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="k">if</span> <span class="p">(</span><span class="n">args</span><span class="o">.</span><span class="n">destination</span> <span class="o">==</span> <span class="kc">None</span><span class="p">):</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="n">parser</span><span class="o">.</span><span class="n">print_help</span><span class="p">()</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">client</span><span class="p">(</span><span class="n">args</span><span class="o">.</span><span class="n">destination</span><span class="p">,</span> <span class="n">configarg</span><span class="p">)</span>
<span class="k">except</span> <span class="ne">KeyboardInterrupt</span><span class="p">:</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="n">exit</span><span class="p">()</span>
</pre></div>
</div>
<p>This example can also be found at <a class="reference external" href="https://github.com/markqvist/Reticulum/blob/master/Examples/Link.py">https://github.com/markqvist/Reticulum/blob/master/Examples/Link.py</a>.</p>
</div>
<div class="section" id="example-identify">
<span id="identification"></span><h2>Identification<a class="headerlink" href="#example-identify" title="Permalink to this headline"></a></h2>
<p>The <em>Identify</em> example explores identifying an intiator of a link, once
the link has been established.</p>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="c1">##########################################################</span>
<span class="c1"># This RNS example demonstrates how to set up a link to #</span>
<span class="c1"># a destination, and identify the initiator to it&#39;s peer #</span>
<span class="c1">##########################################################</span>
<span class="kn">import</span> <span class="nn">os</span>
<span class="kn">import</span> <span class="nn">sys</span>
<span class="kn">import</span> <span class="nn">time</span>
<span class="kn">import</span> <span class="nn">argparse</span>
<span class="kn">import</span> <span class="nn">RNS</span>
<span class="c1"># Let&#39;s define an app name. We&#39;ll use this for all</span>
<span class="c1"># destinations we create. Since this echo example</span>
<span class="c1"># is part of a range of example utilities, we&#39;ll put</span>
<span class="c1"># them all within the app namespace &quot;example_utilities&quot;</span>
<span class="n">APP_NAME</span> <span class="o">=</span> <span class="s2">&quot;example_utilities&quot;</span>
<span class="c1">##########################################################</span>
<span class="c1">#### Server Part #########################################</span>
<span class="c1">##########################################################</span>
<span class="c1"># A reference to the latest client link that connected</span>
<span class="n">latest_client_link</span> <span class="o">=</span> <span class="kc">None</span>
<span class="c1"># This initialisation is executed when the users chooses</span>
<span class="c1"># to run as a server</span>
<span class="k">def</span> <span class="nf">server</span><span class="p">(</span><span class="n">configpath</span><span class="p">):</span>
<span class="c1"># We must first initialise Reticulum</span>
<span class="n">reticulum</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Reticulum</span><span class="p">(</span><span class="n">configpath</span><span class="p">)</span>
<span class="c1"># Randomly create a new identity for our link example</span>
<span class="n">server_identity</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Identity</span><span class="p">()</span>
<span class="c1"># We create a destination that clients can connect to. We</span>
<span class="c1"># want clients to create links to this destination, so we</span>
<span class="c1"># need to create a &quot;single&quot; destination type.</span>
<span class="n">server_destination</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="p">(</span>
<span class="n">server_identity</span><span class="p">,</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">IN</span><span class="p">,</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">SINGLE</span><span class="p">,</span>
<span class="n">APP_NAME</span><span class="p">,</span>
<span class="s2">&quot;identifyexample&quot;</span>
<span class="p">)</span>
<span class="c1"># We configure a function that will get called every time</span>
<span class="c1"># a new client creates a link to this destination.</span>
<span class="n">server_destination</span><span class="o">.</span><span class="n">set_link_established_callback</span><span class="p">(</span><span class="n">client_connected</span><span class="p">)</span>
<span class="c1"># Everything&#39;s ready!</span>
<span class="c1"># Let&#39;s Wait for client requests or user input</span>
<span class="n">server_loop</span><span class="p">(</span><span class="n">server_destination</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">server_loop</span><span class="p">(</span><span class="n">destination</span><span class="p">):</span>
<span class="c1"># Let the user know that everything is ready</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span>
<span class="s2">&quot;Link identification example &quot;</span><span class="o">+</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">prettyhexrep</span><span class="p">(</span><span class="n">destination</span><span class="o">.</span><span class="n">hash</span><span class="p">)</span><span class="o">+</span>
<span class="s2">&quot; running, waiting for a connection.&quot;</span>
<span class="p">)</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Hit enter to manually send an announce (Ctrl-C to quit)&quot;</span><span class="p">)</span>
<span class="c1"># We enter a loop that runs until the users exits.</span>
<span class="c1"># If the user hits enter, we will announce our server</span>
<span class="c1"># destination on the network, which will let clients</span>
<span class="c1"># know how to create messages directed towards it.</span>
<span class="k">while</span> <span class="kc">True</span><span class="p">:</span>
<span class="n">entered</span> <span class="o">=</span> <span class="nb">input</span><span class="p">()</span>
<span class="n">destination</span><span class="o">.</span><span class="n">announce</span><span class="p">()</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Sent announce from &quot;</span><span class="o">+</span><span class="n">RNS</span><span class="o">.</span><span class="n">prettyhexrep</span><span class="p">(</span><span class="n">destination</span><span class="o">.</span><span class="n">hash</span><span class="p">))</span>
<span class="c1"># When a client establishes a link to our server</span>
<span class="c1"># destination, this function will be called with</span>
<span class="c1"># a reference to the link.</span>
<span class="k">def</span> <span class="nf">client_connected</span><span class="p">(</span><span class="n">link</span><span class="p">):</span>
<span class="k">global</span> <span class="n">latest_client_link</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Client connected&quot;</span><span class="p">)</span>
<span class="n">link</span><span class="o">.</span><span class="n">set_link_closed_callback</span><span class="p">(</span><span class="n">client_disconnected</span><span class="p">)</span>
<span class="n">link</span><span class="o">.</span><span class="n">set_packet_callback</span><span class="p">(</span><span class="n">server_packet_received</span><span class="p">)</span>
<span class="n">link</span><span class="o">.</span><span class="n">set_remote_identified_callback</span><span class="p">(</span><span class="n">remote_identified</span><span class="p">)</span>
<span class="n">latest_client_link</span> <span class="o">=</span> <span class="n">link</span>
<span class="k">def</span> <span class="nf">client_disconnected</span><span class="p">(</span><span class="n">link</span><span class="p">):</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Client disconnected&quot;</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">remote_identified</span><span class="p">(</span><span class="n">identity</span><span class="p">):</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Remote identified as: &quot;</span><span class="o">+</span><span class="nb">str</span><span class="p">(</span><span class="n">identity</span><span class="p">))</span>
<span class="k">def</span> <span class="nf">server_packet_received</span><span class="p">(</span><span class="n">message</span><span class="p">,</span> <span class="n">packet</span><span class="p">):</span>
<span class="k">global</span> <span class="n">latest_client_link</span>
<span class="c1"># Get the originating identity for display</span>
<span class="n">remote_peer</span> <span class="o">=</span> <span class="s2">&quot;unidentified peer&quot;</span>
<span class="k">if</span> <span class="n">packet</span><span class="o">.</span><span class="n">link</span><span class="o">.</span><span class="n">get_remote_identity</span><span class="p">()</span> <span class="o">!=</span> <span class="kc">None</span><span class="p">:</span>
<span class="n">remote_peer</span> <span class="o">=</span> <span class="nb">str</span><span class="p">(</span><span class="n">packet</span><span class="o">.</span><span class="n">link</span><span class="o">.</span><span class="n">get_remote_identity</span><span class="p">())</span>
<span class="c1"># When data is received over any active link,</span>
<span class="c1"># it will all be directed to the last client</span>
<span class="c1"># that connected.</span>
<span class="n">text</span> <span class="o">=</span> <span class="n">message</span><span class="o">.</span><span class="n">decode</span><span class="p">(</span><span class="s2">&quot;utf-8&quot;</span><span class="p">)</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Received data from &quot;</span><span class="o">+</span><span class="n">remote_peer</span><span class="o">+</span><span class="s2">&quot;: &quot;</span><span class="o">+</span><span class="n">text</span><span class="p">)</span>
<span class="n">reply_text</span> <span class="o">=</span> <span class="s2">&quot;I received </span><span class="se">\&quot;</span><span class="s2">&quot;</span><span class="o">+</span><span class="n">text</span><span class="o">+</span><span class="s2">&quot;</span><span class="se">\&quot;</span><span class="s2"> over the link from &quot;</span><span class="o">+</span><span class="n">remote_peer</span>
<span class="n">reply_data</span> <span class="o">=</span> <span class="n">reply_text</span><span class="o">.</span><span class="n">encode</span><span class="p">(</span><span class="s2">&quot;utf-8&quot;</span><span class="p">)</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Packet</span><span class="p">(</span><span class="n">latest_client_link</span><span class="p">,</span> <span class="n">reply_data</span><span class="p">)</span><span class="o">.</span><span class="n">send</span><span class="p">()</span>
<span class="c1">##########################################################</span>
<span class="c1">#### Client Part #########################################</span>
<span class="c1">##########################################################</span>
<span class="c1"># A reference to the server link</span>
<span class="n">server_link</span> <span class="o">=</span> <span class="kc">None</span>
<span class="c1"># A reference to the client identity</span>
<span class="n">client_identity</span> <span class="o">=</span> <span class="kc">None</span>
<span class="c1"># This initialisation is executed when the users chooses</span>
<span class="c1"># to run as a client</span>
<span class="k">def</span> <span class="nf">client</span><span class="p">(</span><span class="n">destination_hexhash</span><span class="p">,</span> <span class="n">configpath</span><span class="p">):</span>
<span class="k">global</span> <span class="n">client_identity</span>
<span class="c1"># We need a binary representation of the destination</span>
<span class="c1"># hash that was entered on the command line</span>
<span class="k">try</span><span class="p">:</span>
<span class="k">if</span> <span class="nb">len</span><span class="p">(</span><span class="n">destination_hexhash</span><span class="p">)</span> <span class="o">!=</span> <span class="mi">20</span><span class="p">:</span>
<span class="k">raise</span> <span class="ne">ValueError</span><span class="p">(</span><span class="s2">&quot;Destination length is invalid, must be 20 hexadecimal characters (10 bytes)&quot;</span><span class="p">)</span>
<span class="n">destination_hash</span> <span class="o">=</span> <span class="nb">bytes</span><span class="o">.</span><span class="n">fromhex</span><span class="p">(</span><span class="n">destination_hexhash</span><span class="p">)</span>
<span class="k">except</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Invalid destination entered. Check your input!</span><span class="se">\n</span><span class="s2">&quot;</span><span class="p">)</span>
<span class="n">exit</span><span class="p">()</span>
<span class="c1"># We must first initialise Reticulum</span>
<span class="n">reticulum</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Reticulum</span><span class="p">(</span><span class="n">configpath</span><span class="p">)</span>
<span class="c1"># Create a new client identity</span>
<span class="n">client_identity</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Identity</span><span class="p">()</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span>
<span class="s2">&quot;Client created new identity &quot;</span><span class="o">+</span>
<span class="nb">str</span><span class="p">(</span><span class="n">client_identity</span><span class="p">)</span>
<span class="p">)</span>
<span class="c1"># Check if we know a path to the destination</span>
<span class="k">if</span> <span class="ow">not</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Transport</span><span class="o">.</span><span class="n">has_path</span><span class="p">(</span><span class="n">destination_hash</span><span class="p">):</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Destination is not yet known. Requesting path and waiting for announce to arrive...&quot;</span><span class="p">)</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Transport</span><span class="o">.</span><span class="n">request_path</span><span class="p">(</span><span class="n">destination_hash</span><span class="p">)</span>
<span class="k">while</span> <span class="ow">not</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Transport</span><span class="o">.</span><span class="n">has_path</span><span class="p">(</span><span class="n">destination_hash</span><span class="p">):</span>
<span class="n">time</span><span class="o">.</span><span class="n">sleep</span><span class="p">(</span><span class="mf">0.1</span><span class="p">)</span>
<span class="c1"># Recall the server identity</span>
<span class="n">server_identity</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Identity</span><span class="o">.</span><span class="n">recall</span><span class="p">(</span><span class="n">destination_hash</span><span class="p">)</span>
<span class="c1"># Inform the user that we&#39;ll begin connecting</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Establishing link with server...&quot;</span><span class="p">)</span>
<span class="c1"># When the server identity is known, we set</span>
<span class="c1"># up a destination</span>
<span class="n">server_destination</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="p">(</span>
<span class="n">server_identity</span><span class="p">,</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">OUT</span><span class="p">,</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">SINGLE</span><span class="p">,</span>
<span class="n">APP_NAME</span><span class="p">,</span>
<span class="s2">&quot;identifyexample&quot;</span>
<span class="p">)</span>
<span class="c1"># And create a link</span>
<span class="n">link</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Link</span><span class="p">(</span><span class="n">server_destination</span><span class="p">)</span>
<span class="c1"># We set a callback that will get executed</span>
<span class="c1"># every time a packet is received over the</span>
<span class="c1"># link</span>
<span class="n">link</span><span class="o">.</span><span class="n">set_packet_callback</span><span class="p">(</span><span class="n">client_packet_received</span><span class="p">)</span>
<span class="c1"># We&#39;ll also set up functions to inform the</span>
<span class="c1"># user when the link is established or closed</span>
<span class="n">link</span><span class="o">.</span><span class="n">set_link_established_callback</span><span class="p">(</span><span class="n">link_established</span><span class="p">)</span>
<span class="n">link</span><span class="o">.</span><span class="n">set_link_closed_callback</span><span class="p">(</span><span class="n">link_closed</span><span class="p">)</span>
<span class="c1"># Everything is set up, so let&#39;s enter a loop</span>
<span class="c1"># for the user to interact with the example</span>
<span class="n">client_loop</span><span class="p">()</span>
<span class="k">def</span> <span class="nf">client_loop</span><span class="p">():</span>
<span class="k">global</span> <span class="n">server_link</span>
<span class="c1"># Wait for the link to become active</span>
<span class="k">while</span> <span class="ow">not</span> <span class="n">server_link</span><span class="p">:</span>
<span class="n">time</span><span class="o">.</span><span class="n">sleep</span><span class="p">(</span><span class="mf">0.1</span><span class="p">)</span>
<span class="n">should_quit</span> <span class="o">=</span> <span class="kc">False</span>
<span class="k">while</span> <span class="ow">not</span> <span class="n">should_quit</span><span class="p">:</span>
<span class="k">try</span><span class="p">:</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&gt; &quot;</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="s2">&quot; &quot;</span><span class="p">)</span>
<span class="n">text</span> <span class="o">=</span> <span class="nb">input</span><span class="p">()</span>
<span class="c1"># Check if we should quit the example</span>
<span class="k">if</span> <span class="n">text</span> <span class="o">==</span> <span class="s2">&quot;quit&quot;</span> <span class="ow">or</span> <span class="n">text</span> <span class="o">==</span> <span class="s2">&quot;q&quot;</span> <span class="ow">or</span> <span class="n">text</span> <span class="o">==</span> <span class="s2">&quot;exit&quot;</span><span class="p">:</span>
<span class="n">should_quit</span> <span class="o">=</span> <span class="kc">True</span>
<span class="n">server_link</span><span class="o">.</span><span class="n">teardown</span><span class="p">()</span>
<span class="c1"># If not, send the entered text over the link</span>
<span class="k">if</span> <span class="n">text</span> <span class="o">!=</span> <span class="s2">&quot;&quot;</span><span class="p">:</span>
<span class="n">data</span> <span class="o">=</span> <span class="n">text</span><span class="o">.</span><span class="n">encode</span><span class="p">(</span><span class="s2">&quot;utf-8&quot;</span><span class="p">)</span>
<span class="k">if</span> <span class="nb">len</span><span class="p">(</span><span class="n">data</span><span class="p">)</span> <span class="o">&lt;=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Link</span><span class="o">.</span><span class="n">MDU</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Packet</span><span class="p">(</span><span class="n">server_link</span><span class="p">,</span> <span class="n">data</span><span class="p">)</span><span class="o">.</span><span class="n">send</span><span class="p">()</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span>
<span class="s2">&quot;Cannot send this packet, the data size of &quot;</span><span class="o">+</span>
<span class="nb">str</span><span class="p">(</span><span class="nb">len</span><span class="p">(</span><span class="n">data</span><span class="p">))</span><span class="o">+</span><span class="s2">&quot; bytes exceeds the link packet MDU of &quot;</span><span class="o">+</span>
<span class="nb">str</span><span class="p">(</span><span class="n">RNS</span><span class="o">.</span><span class="n">Link</span><span class="o">.</span><span class="n">MDU</span><span class="p">)</span><span class="o">+</span><span class="s2">&quot; bytes&quot;</span><span class="p">,</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">LOG_ERROR</span>
<span class="p">)</span>
<span class="k">except</span> <span class="ne">Exception</span> <span class="k">as</span> <span class="n">e</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Error while sending data over the link: &quot;</span><span class="o">+</span><span class="nb">str</span><span class="p">(</span><span class="n">e</span><span class="p">))</span>
<span class="n">should_quit</span> <span class="o">=</span> <span class="kc">True</span>
<span class="n">server_link</span><span class="o">.</span><span class="n">teardown</span><span class="p">()</span>
<span class="c1"># This function is called when a link</span>
<span class="c1"># has been established with the server</span>
<span class="k">def</span> <span class="nf">link_established</span><span class="p">(</span><span class="n">link</span><span class="p">):</span>
<span class="c1"># We store a reference to the link</span>
<span class="c1"># instance for later use</span>
<span class="k">global</span> <span class="n">server_link</span><span class="p">,</span> <span class="n">client_identity</span>
<span class="n">server_link</span> <span class="o">=</span> <span class="n">link</span>
<span class="c1"># Inform the user that the server is</span>
<span class="c1"># connected</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Link established with server, identifying to remote peer...&quot;</span><span class="p">)</span>
<span class="n">link</span><span class="o">.</span><span class="n">identify</span><span class="p">(</span><span class="n">client_identity</span><span class="p">)</span>
<span class="c1"># When a link is closed, we&#39;ll inform the</span>
<span class="c1"># user, and exit the program</span>
<span class="k">def</span> <span class="nf">link_closed</span><span class="p">(</span><span class="n">link</span><span class="p">):</span>
<span class="k">if</span> <span class="n">link</span><span class="o">.</span><span class="n">teardown_reason</span> <span class="o">==</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Link</span><span class="o">.</span><span class="n">TIMEOUT</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;The link timed out, exiting now&quot;</span><span class="p">)</span>
<span class="k">elif</span> <span class="n">link</span><span class="o">.</span><span class="n">teardown_reason</span> <span class="o">==</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Link</span><span class="o">.</span><span class="n">DESTINATION_CLOSED</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;The link was closed by the server, exiting now&quot;</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Link closed, exiting now&quot;</span><span class="p">)</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Reticulum</span><span class="o">.</span><span class="n">exit_handler</span><span class="p">()</span>
<span class="n">time</span><span class="o">.</span><span class="n">sleep</span><span class="p">(</span><span class="mf">1.5</span><span class="p">)</span>
<span class="n">os</span><span class="o">.</span><span class="n">_exit</span><span class="p">(</span><span class="mi">0</span><span class="p">)</span>
<span class="c1"># When a packet is received over the link, we</span>
<span class="c1"># simply print out the data.</span>
<span class="k">def</span> <span class="nf">client_packet_received</span><span class="p">(</span><span class="n">message</span><span class="p">,</span> <span class="n">packet</span><span class="p">):</span>
<span class="n">text</span> <span class="o">=</span> <span class="n">message</span><span class="o">.</span><span class="n">decode</span><span class="p">(</span><span class="s2">&quot;utf-8&quot;</span><span class="p">)</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Received data on the link: &quot;</span><span class="o">+</span><span class="n">text</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&gt; &quot;</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="s2">&quot; &quot;</span><span class="p">)</span>
<span class="n">sys</span><span class="o">.</span><span class="n">stdout</span><span class="o">.</span><span class="n">flush</span><span class="p">()</span>
<span class="c1">##########################################################</span>
<span class="c1">#### Program Startup #####################################</span>
<span class="c1">##########################################################</span>
<span class="c1"># This part of the program runs at startup,</span>
<span class="c1"># and parses input of from the user, and then</span>
<span class="c1"># starts up the desired program mode.</span>
<span class="k">if</span> <span class="vm">__name__</span> <span class="o">==</span> <span class="s2">&quot;__main__&quot;</span><span class="p">:</span>
<span class="k">try</span><span class="p">:</span>
<span class="n">parser</span> <span class="o">=</span> <span class="n">argparse</span><span class="o">.</span><span class="n">ArgumentParser</span><span class="p">(</span><span class="n">description</span><span class="o">=</span><span class="s2">&quot;Simple link example&quot;</span><span class="p">)</span>
<span class="n">parser</span><span class="o">.</span><span class="n">add_argument</span><span class="p">(</span>
<span class="s2">&quot;-s&quot;</span><span class="p">,</span>
<span class="s2">&quot;--server&quot;</span><span class="p">,</span>
<span class="n">action</span><span class="o">=</span><span class="s2">&quot;store_true&quot;</span><span class="p">,</span>
<span class="n">help</span><span class="o">=</span><span class="s2">&quot;wait for incoming link requests from clients&quot;</span>
<span class="p">)</span>
<span class="n">parser</span><span class="o">.</span><span class="n">add_argument</span><span class="p">(</span>
<span class="s2">&quot;--config&quot;</span><span class="p">,</span>
<span class="n">action</span><span class="o">=</span><span class="s2">&quot;store&quot;</span><span class="p">,</span>
<span class="n">default</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span>
<span class="n">help</span><span class="o">=</span><span class="s2">&quot;path to alternative Reticulum config directory&quot;</span><span class="p">,</span>
<span class="nb">type</span><span class="o">=</span><span class="nb">str</span>
<span class="p">)</span>
<span class="n">parser</span><span class="o">.</span><span class="n">add_argument</span><span class="p">(</span>
<span class="s2">&quot;destination&quot;</span><span class="p">,</span>
<span class="n">nargs</span><span class="o">=</span><span class="s2">&quot;?&quot;</span><span class="p">,</span>
<span class="n">default</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span>
<span class="n">help</span><span class="o">=</span><span class="s2">&quot;hexadecimal hash of the server destination&quot;</span><span class="p">,</span>
<span class="nb">type</span><span class="o">=</span><span class="nb">str</span>
<span class="p">)</span>
<span class="n">args</span> <span class="o">=</span> <span class="n">parser</span><span class="o">.</span><span class="n">parse_args</span><span class="p">()</span>
<span class="k">if</span> <span class="n">args</span><span class="o">.</span><span class="n">config</span><span class="p">:</span>
<span class="n">configarg</span> <span class="o">=</span> <span class="n">args</span><span class="o">.</span><span class="n">config</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">configarg</span> <span class="o">=</span> <span class="kc">None</span>
<span class="k">if</span> <span class="n">args</span><span class="o">.</span><span class="n">server</span><span class="p">:</span>
<span class="n">server</span><span class="p">(</span><span class="n">configarg</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="k">if</span> <span class="p">(</span><span class="n">args</span><span class="o">.</span><span class="n">destination</span> <span class="o">==</span> <span class="kc">None</span><span class="p">):</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="n">parser</span><span class="o">.</span><span class="n">print_help</span><span class="p">()</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">client</span><span class="p">(</span><span class="n">args</span><span class="o">.</span><span class="n">destination</span><span class="p">,</span> <span class="n">configarg</span><span class="p">)</span>
<span class="k">except</span> <span class="ne">KeyboardInterrupt</span><span class="p">:</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="n">exit</span><span class="p">()</span>
</pre></div>
</div>
<p>This example can also be found at <a class="reference external" href="https://github.com/markqvist/Reticulum/blob/master/Examples/Identify.py">https://github.com/markqvist/Reticulum/blob/master/Examples/Identify.py</a>.</p>
</div>
<div class="section" id="requests-responses">
<span id="example-request"></span><h2>Requests &amp; Responses<a class="headerlink" href="#requests-responses" title="Permalink to this headline"></a></h2>
<p>The <em>Request</em> example explores sendig requests and receiving responses.</p>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="c1">##########################################################</span>
<span class="c1"># This RNS example demonstrates how to set perform #</span>
<span class="c1"># requests and receive responses over a link. #</span>
<span class="c1">##########################################################</span>
<span class="kn">import</span> <span class="nn">os</span>
<span class="kn">import</span> <span class="nn">sys</span>
<span class="kn">import</span> <span class="nn">time</span>
<span class="kn">import</span> <span class="nn">random</span>
<span class="kn">import</span> <span class="nn">argparse</span>
<span class="kn">import</span> <span class="nn">RNS</span>
<span class="c1"># Let&#39;s define an app name. We&#39;ll use this for all</span>
<span class="c1"># destinations we create. Since this echo example</span>
<span class="c1"># is part of a range of example utilities, we&#39;ll put</span>
<span class="c1"># them all within the app namespace &quot;example_utilities&quot;</span>
<span class="n">APP_NAME</span> <span class="o">=</span> <span class="s2">&quot;example_utilities&quot;</span>
<span class="c1">##########################################################</span>
<span class="c1">#### Server Part #########################################</span>
<span class="c1">##########################################################</span>
<span class="c1"># A reference to the latest client link that connected</span>
<span class="n">latest_client_link</span> <span class="o">=</span> <span class="kc">None</span>
<span class="k">def</span> <span class="nf">random_text_generator</span><span class="p">(</span><span class="n">path</span><span class="p">,</span> <span class="n">data</span><span class="p">,</span> <span class="n">request_id</span><span class="p">,</span> <span class="n">remote_identity</span><span class="p">,</span> <span class="n">requested_at</span><span class="p">):</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Generating response to request &quot;</span><span class="o">+</span><span class="n">RNS</span><span class="o">.</span><span class="n">prettyhexrep</span><span class="p">(</span><span class="n">request_id</span><span class="p">))</span>
<span class="n">texts</span> <span class="o">=</span> <span class="p">[</span><span class="s2">&quot;They looked up&quot;</span><span class="p">,</span> <span class="s2">&quot;On each full moon&quot;</span><span class="p">,</span> <span class="s2">&quot;Becky was upset&quot;</span><span class="p">,</span> <span class="s2">&quot;Ill stay away from it&quot;</span><span class="p">,</span> <span class="s2">&quot;The pet shop stocks everything&quot;</span><span class="p">]</span>
<span class="k">return</span> <span class="n">texts</span><span class="p">[</span><span class="n">random</span><span class="o">.</span><span class="n">randint</span><span class="p">(</span><span class="mi">0</span><span class="p">,</span> <span class="nb">len</span><span class="p">(</span><span class="n">texts</span><span class="p">)</span><span class="o">-</span><span class="mi">1</span><span class="p">)]</span>
<span class="c1"># This initialisation is executed when the users chooses</span>
<span class="c1"># to run as a server</span>
<span class="k">def</span> <span class="nf">server</span><span class="p">(</span><span class="n">configpath</span><span class="p">):</span>
<span class="c1"># We must first initialise Reticulum</span>
<span class="n">reticulum</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Reticulum</span><span class="p">(</span><span class="n">configpath</span><span class="p">)</span>
<span class="c1"># Randomly create a new identity for our link example</span>
<span class="n">server_identity</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Identity</span><span class="p">()</span>
<span class="c1"># We create a destination that clients can connect to. We</span>
<span class="c1"># want clients to create links to this destination, so we</span>
<span class="c1"># need to create a &quot;single&quot; destination type.</span>
<span class="n">server_destination</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="p">(</span>
<span class="n">server_identity</span><span class="p">,</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">IN</span><span class="p">,</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">SINGLE</span><span class="p">,</span>
<span class="n">APP_NAME</span><span class="p">,</span>
<span class="s2">&quot;requestexample&quot;</span>
<span class="p">)</span>
<span class="c1"># We configure a function that will get called every time</span>
<span class="c1"># a new client creates a link to this destination.</span>
<span class="n">server_destination</span><span class="o">.</span><span class="n">set_link_established_callback</span><span class="p">(</span><span class="n">client_connected</span><span class="p">)</span>
<span class="c1"># We register a request handler for handling incoming</span>
<span class="c1"># requests over any established links.</span>
<span class="n">server_destination</span><span class="o">.</span><span class="n">register_request_handler</span><span class="p">(</span>
<span class="s2">&quot;/random/text&quot;</span><span class="p">,</span>
<span class="n">response_generator</span> <span class="o">=</span> <span class="n">random_text_generator</span><span class="p">,</span>
<span class="n">allow</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">ALLOW_ALL</span>
<span class="p">)</span>
<span class="c1"># Everything&#39;s ready!</span>
<span class="c1"># Let&#39;s Wait for client requests or user input</span>
<span class="n">server_loop</span><span class="p">(</span><span class="n">server_destination</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">server_loop</span><span class="p">(</span><span class="n">destination</span><span class="p">):</span>
<span class="c1"># Let the user know that everything is ready</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span>
<span class="s2">&quot;Request example &quot;</span><span class="o">+</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">prettyhexrep</span><span class="p">(</span><span class="n">destination</span><span class="o">.</span><span class="n">hash</span><span class="p">)</span><span class="o">+</span>
<span class="s2">&quot; running, waiting for a connection.&quot;</span>
<span class="p">)</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Hit enter to manually send an announce (Ctrl-C to quit)&quot;</span><span class="p">)</span>
<span class="c1"># We enter a loop that runs until the users exits.</span>
<span class="c1"># If the user hits enter, we will announce our server</span>
<span class="c1"># destination on the network, which will let clients</span>
<span class="c1"># know how to create messages directed towards it.</span>
<span class="k">while</span> <span class="kc">True</span><span class="p">:</span>
<span class="n">entered</span> <span class="o">=</span> <span class="nb">input</span><span class="p">()</span>
<span class="n">destination</span><span class="o">.</span><span class="n">announce</span><span class="p">()</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Sent announce from &quot;</span><span class="o">+</span><span class="n">RNS</span><span class="o">.</span><span class="n">prettyhexrep</span><span class="p">(</span><span class="n">destination</span><span class="o">.</span><span class="n">hash</span><span class="p">))</span>
<span class="c1"># When a client establishes a link to our server</span>
<span class="c1"># destination, this function will be called with</span>
<span class="c1"># a reference to the link.</span>
<span class="k">def</span> <span class="nf">client_connected</span><span class="p">(</span><span class="n">link</span><span class="p">):</span>
<span class="k">global</span> <span class="n">latest_client_link</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Client connected&quot;</span><span class="p">)</span>
<span class="n">link</span><span class="o">.</span><span class="n">set_link_closed_callback</span><span class="p">(</span><span class="n">client_disconnected</span><span class="p">)</span>
<span class="n">latest_client_link</span> <span class="o">=</span> <span class="n">link</span>
<span class="k">def</span> <span class="nf">client_disconnected</span><span class="p">(</span><span class="n">link</span><span class="p">):</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Client disconnected&quot;</span><span class="p">)</span>
<span class="c1">##########################################################</span>
<span class="c1">#### Client Part #########################################</span>
<span class="c1">##########################################################</span>
<span class="c1"># A reference to the server link</span>
<span class="n">server_link</span> <span class="o">=</span> <span class="kc">None</span>
<span class="c1"># This initialisation is executed when the users chooses</span>
<span class="c1"># to run as a client</span>
<span class="k">def</span> <span class="nf">client</span><span class="p">(</span><span class="n">destination_hexhash</span><span class="p">,</span> <span class="n">configpath</span><span class="p">):</span>
<span class="c1"># We need a binary representation of the destination</span>
<span class="c1"># hash that was entered on the command line</span>
<span class="k">try</span><span class="p">:</span>
<span class="k">if</span> <span class="nb">len</span><span class="p">(</span><span class="n">destination_hexhash</span><span class="p">)</span> <span class="o">!=</span> <span class="mi">20</span><span class="p">:</span>
<span class="k">raise</span> <span class="ne">ValueError</span><span class="p">(</span><span class="s2">&quot;Destination length is invalid, must be 20 hexadecimal characters (10 bytes)&quot;</span><span class="p">)</span>
<span class="n">destination_hash</span> <span class="o">=</span> <span class="nb">bytes</span><span class="o">.</span><span class="n">fromhex</span><span class="p">(</span><span class="n">destination_hexhash</span><span class="p">)</span>
<span class="k">except</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Invalid destination entered. Check your input!</span><span class="se">\n</span><span class="s2">&quot;</span><span class="p">)</span>
<span class="n">exit</span><span class="p">()</span>
<span class="c1"># We must first initialise Reticulum</span>
<span class="n">reticulum</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Reticulum</span><span class="p">(</span><span class="n">configpath</span><span class="p">)</span>
<span class="c1"># Check if we know a path to the destination</span>
<span class="k">if</span> <span class="ow">not</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Transport</span><span class="o">.</span><span class="n">has_path</span><span class="p">(</span><span class="n">destination_hash</span><span class="p">):</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Destination is not yet known. Requesting path and waiting for announce to arrive...&quot;</span><span class="p">)</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Transport</span><span class="o">.</span><span class="n">request_path</span><span class="p">(</span><span class="n">destination_hash</span><span class="p">)</span>
<span class="k">while</span> <span class="ow">not</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Transport</span><span class="o">.</span><span class="n">has_path</span><span class="p">(</span><span class="n">destination_hash</span><span class="p">):</span>
<span class="n">time</span><span class="o">.</span><span class="n">sleep</span><span class="p">(</span><span class="mf">0.1</span><span class="p">)</span>
<span class="c1"># Recall the server identity</span>
<span class="n">server_identity</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Identity</span><span class="o">.</span><span class="n">recall</span><span class="p">(</span><span class="n">destination_hash</span><span class="p">)</span>
<span class="c1"># Inform the user that we&#39;ll begin connecting</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Establishing link with server...&quot;</span><span class="p">)</span>
<span class="c1"># When the server identity is known, we set</span>
<span class="c1"># up a destination</span>
<span class="n">server_destination</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="p">(</span>
<span class="n">server_identity</span><span class="p">,</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">OUT</span><span class="p">,</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">SINGLE</span><span class="p">,</span>
<span class="n">APP_NAME</span><span class="p">,</span>
<span class="s2">&quot;requestexample&quot;</span>
<span class="p">)</span>
<span class="c1"># And create a link</span>
<span class="n">link</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Link</span><span class="p">(</span><span class="n">server_destination</span><span class="p">)</span>
<span class="c1"># We&#39;ll set up functions to inform the</span>
<span class="c1"># user when the link is established or closed</span>
<span class="n">link</span><span class="o">.</span><span class="n">set_link_established_callback</span><span class="p">(</span><span class="n">link_established</span><span class="p">)</span>
<span class="n">link</span><span class="o">.</span><span class="n">set_link_closed_callback</span><span class="p">(</span><span class="n">link_closed</span><span class="p">)</span>
<span class="c1"># Everything is set up, so let&#39;s enter a loop</span>
<span class="c1"># for the user to interact with the example</span>
<span class="n">client_loop</span><span class="p">()</span>
<span class="k">def</span> <span class="nf">client_loop</span><span class="p">():</span>
<span class="k">global</span> <span class="n">server_link</span>
<span class="c1"># Wait for the link to become active</span>
<span class="k">while</span> <span class="ow">not</span> <span class="n">server_link</span><span class="p">:</span>
<span class="n">time</span><span class="o">.</span><span class="n">sleep</span><span class="p">(</span><span class="mf">0.1</span><span class="p">)</span>
<span class="n">should_quit</span> <span class="o">=</span> <span class="kc">False</span>
<span class="k">while</span> <span class="ow">not</span> <span class="n">should_quit</span><span class="p">:</span>
<span class="k">try</span><span class="p">:</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&gt; &quot;</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="s2">&quot; &quot;</span><span class="p">)</span>
<span class="n">text</span> <span class="o">=</span> <span class="nb">input</span><span class="p">()</span>
<span class="c1"># Check if we should quit the example</span>
<span class="k">if</span> <span class="n">text</span> <span class="o">==</span> <span class="s2">&quot;quit&quot;</span> <span class="ow">or</span> <span class="n">text</span> <span class="o">==</span> <span class="s2">&quot;q&quot;</span> <span class="ow">or</span> <span class="n">text</span> <span class="o">==</span> <span class="s2">&quot;exit&quot;</span><span class="p">:</span>
<span class="n">should_quit</span> <span class="o">=</span> <span class="kc">True</span>
<span class="n">server_link</span><span class="o">.</span><span class="n">teardown</span><span class="p">()</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">server_link</span><span class="o">.</span><span class="n">request</span><span class="p">(</span>
<span class="s2">&quot;/random/text&quot;</span><span class="p">,</span>
<span class="n">data</span> <span class="o">=</span> <span class="kc">None</span><span class="p">,</span>
<span class="n">response_callback</span> <span class="o">=</span> <span class="n">got_response</span><span class="p">,</span>
<span class="n">failed_callback</span> <span class="o">=</span> <span class="n">request_failed</span>
<span class="p">)</span>
<span class="k">except</span> <span class="ne">Exception</span> <span class="k">as</span> <span class="n">e</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Error while sending request over the link: &quot;</span><span class="o">+</span><span class="nb">str</span><span class="p">(</span><span class="n">e</span><span class="p">))</span>
<span class="n">should_quit</span> <span class="o">=</span> <span class="kc">True</span>
<span class="n">server_link</span><span class="o">.</span><span class="n">teardown</span><span class="p">()</span>
<span class="k">def</span> <span class="nf">got_response</span><span class="p">(</span><span class="n">request_receipt</span><span class="p">):</span>
<span class="n">request_id</span> <span class="o">=</span> <span class="n">request_receipt</span><span class="o">.</span><span class="n">request_id</span>
<span class="n">response</span> <span class="o">=</span> <span class="n">request_receipt</span><span class="o">.</span><span class="n">response</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Got response for request &quot;</span><span class="o">+</span><span class="n">RNS</span><span class="o">.</span><span class="n">prettyhexrep</span><span class="p">(</span><span class="n">request_id</span><span class="p">)</span><span class="o">+</span><span class="s2">&quot;: &quot;</span><span class="o">+</span><span class="nb">str</span><span class="p">(</span><span class="n">response</span><span class="p">))</span>
<span class="k">def</span> <span class="nf">request_received</span><span class="p">(</span><span class="n">request_receipt</span><span class="p">):</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;The request &quot;</span><span class="o">+</span><span class="n">RNS</span><span class="o">.</span><span class="n">prettyhexrep</span><span class="p">(</span><span class="n">request_receipt</span><span class="o">.</span><span class="n">request_id</span><span class="p">)</span><span class="o">+</span><span class="s2">&quot; was received by the remote peer.&quot;</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">request_failed</span><span class="p">(</span><span class="n">request_receipt</span><span class="p">):</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;The request &quot;</span><span class="o">+</span><span class="n">RNS</span><span class="o">.</span><span class="n">prettyhexrep</span><span class="p">(</span><span class="n">request_receipt</span><span class="o">.</span><span class="n">request_id</span><span class="p">)</span><span class="o">+</span><span class="s2">&quot; failed.&quot;</span><span class="p">)</span>
<span class="c1"># This function is called when a link</span>
<span class="c1"># has been established with the server</span>
<span class="k">def</span> <span class="nf">link_established</span><span class="p">(</span><span class="n">link</span><span class="p">):</span>
<span class="c1"># We store a reference to the link</span>
<span class="c1"># instance for later use</span>
<span class="k">global</span> <span class="n">server_link</span>
<span class="n">server_link</span> <span class="o">=</span> <span class="n">link</span>
<span class="c1"># Inform the user that the server is</span>
<span class="c1"># connected</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Link established with server, hit enter to perform a request, or type in </span><span class="se">\&quot;</span><span class="s2">quit</span><span class="se">\&quot;</span><span class="s2"> to quit&quot;</span><span class="p">)</span>
<span class="c1"># When a link is closed, we&#39;ll inform the</span>
<span class="c1"># user, and exit the program</span>
<span class="k">def</span> <span class="nf">link_closed</span><span class="p">(</span><span class="n">link</span><span class="p">):</span>
<span class="k">if</span> <span class="n">link</span><span class="o">.</span><span class="n">teardown_reason</span> <span class="o">==</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Link</span><span class="o">.</span><span class="n">TIMEOUT</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;The link timed out, exiting now&quot;</span><span class="p">)</span>
<span class="k">elif</span> <span class="n">link</span><span class="o">.</span><span class="n">teardown_reason</span> <span class="o">==</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Link</span><span class="o">.</span><span class="n">DESTINATION_CLOSED</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;The link was closed by the server, exiting now&quot;</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Link closed, exiting now&quot;</span><span class="p">)</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Reticulum</span><span class="o">.</span><span class="n">exit_handler</span><span class="p">()</span>
<span class="n">time</span><span class="o">.</span><span class="n">sleep</span><span class="p">(</span><span class="mf">1.5</span><span class="p">)</span>
<span class="n">os</span><span class="o">.</span><span class="n">_exit</span><span class="p">(</span><span class="mi">0</span><span class="p">)</span>
<span class="c1">##########################################################</span>
<span class="c1">#### Program Startup #####################################</span>
<span class="c1">##########################################################</span>
<span class="c1"># This part of the program runs at startup,</span>
<span class="c1"># and parses input of from the user, and then</span>
<span class="c1"># starts up the desired program mode.</span>
<span class="k">if</span> <span class="vm">__name__</span> <span class="o">==</span> <span class="s2">&quot;__main__&quot;</span><span class="p">:</span>
<span class="k">try</span><span class="p">:</span>
<span class="n">parser</span> <span class="o">=</span> <span class="n">argparse</span><span class="o">.</span><span class="n">ArgumentParser</span><span class="p">(</span><span class="n">description</span><span class="o">=</span><span class="s2">&quot;Simple request/response example&quot;</span><span class="p">)</span>
<span class="n">parser</span><span class="o">.</span><span class="n">add_argument</span><span class="p">(</span>
<span class="s2">&quot;-s&quot;</span><span class="p">,</span>
<span class="s2">&quot;--server&quot;</span><span class="p">,</span>
<span class="n">action</span><span class="o">=</span><span class="s2">&quot;store_true&quot;</span><span class="p">,</span>
<span class="n">help</span><span class="o">=</span><span class="s2">&quot;wait for incoming requests from clients&quot;</span>
<span class="p">)</span>
<span class="n">parser</span><span class="o">.</span><span class="n">add_argument</span><span class="p">(</span>
<span class="s2">&quot;--config&quot;</span><span class="p">,</span>
<span class="n">action</span><span class="o">=</span><span class="s2">&quot;store&quot;</span><span class="p">,</span>
<span class="n">default</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span>
<span class="n">help</span><span class="o">=</span><span class="s2">&quot;path to alternative Reticulum config directory&quot;</span><span class="p">,</span>
<span class="nb">type</span><span class="o">=</span><span class="nb">str</span>
<span class="p">)</span>
<span class="n">parser</span><span class="o">.</span><span class="n">add_argument</span><span class="p">(</span>
<span class="s2">&quot;destination&quot;</span><span class="p">,</span>
<span class="n">nargs</span><span class="o">=</span><span class="s2">&quot;?&quot;</span><span class="p">,</span>
<span class="n">default</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span>
<span class="n">help</span><span class="o">=</span><span class="s2">&quot;hexadecimal hash of the server destination&quot;</span><span class="p">,</span>
<span class="nb">type</span><span class="o">=</span><span class="nb">str</span>
<span class="p">)</span>
<span class="n">args</span> <span class="o">=</span> <span class="n">parser</span><span class="o">.</span><span class="n">parse_args</span><span class="p">()</span>
<span class="k">if</span> <span class="n">args</span><span class="o">.</span><span class="n">config</span><span class="p">:</span>
<span class="n">configarg</span> <span class="o">=</span> <span class="n">args</span><span class="o">.</span><span class="n">config</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">configarg</span> <span class="o">=</span> <span class="kc">None</span>
<span class="k">if</span> <span class="n">args</span><span class="o">.</span><span class="n">server</span><span class="p">:</span>
<span class="n">server</span><span class="p">(</span><span class="n">configarg</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="k">if</span> <span class="p">(</span><span class="n">args</span><span class="o">.</span><span class="n">destination</span> <span class="o">==</span> <span class="kc">None</span><span class="p">):</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="n">parser</span><span class="o">.</span><span class="n">print_help</span><span class="p">()</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">client</span><span class="p">(</span><span class="n">args</span><span class="o">.</span><span class="n">destination</span><span class="p">,</span> <span class="n">configarg</span><span class="p">)</span>
<span class="k">except</span> <span class="ne">KeyboardInterrupt</span><span class="p">:</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="n">exit</span><span class="p">()</span>
</pre></div>
</div>
<p>This example can also be found at <a class="reference external" href="https://github.com/markqvist/Reticulum/blob/master/Examples/Request.py">https://github.com/markqvist/Reticulum/blob/master/Examples/Request.py</a>.</p>
</div>
<div class="section" id="filetransfer">
<span id="example-filetransfer"></span><h2>Filetransfer<a class="headerlink" href="#filetransfer" title="Permalink to this headline"></a></h2>
<p>The <em>Filetransfer</em> example implements a basic file-server program that
allow clients to connect and download files. The program uses the Resource
interface to efficiently pass files of any size over a Reticulum <a class="reference internal" href="reference.html#api-link"><span class="std std-ref">Link</span></a>.</p>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="c1">##########################################################</span>
<span class="c1"># This RNS example demonstrates a simple filetransfer #</span>
<span class="c1"># server and client program. The server will serve a #</span>
<span class="c1"># directory of files, and the clients can list and #</span>
<span class="c1"># download files from the server. #</span>
<span class="c1"># #</span>
<span class="c1"># Please note that using RNS Resources for large file #</span>
<span class="c1"># transfers is not recommended, since compression, #</span>
<span class="c1"># encryption and hashmap sequencing can take a long time #</span>
<span class="c1"># on systems with slow CPUs, which will probably result #</span>
<span class="c1"># in the client timing out before the resource sender #</span>
<span class="c1"># can complete preparing the resource. #</span>
<span class="c1"># #</span>
<span class="c1"># If you need to transfer large files, use the Bundle #</span>
<span class="c1"># class instead, which will automatically slice the data #</span>
<span class="c1"># into chunks suitable for packing as a Resource. #</span>
<span class="c1">##########################################################</span>
<span class="kn">import</span> <span class="nn">os</span>
<span class="kn">import</span> <span class="nn">sys</span>
<span class="kn">import</span> <span class="nn">time</span>
<span class="kn">import</span> <span class="nn">threading</span>
<span class="kn">import</span> <span class="nn">argparse</span>
<span class="kn">import</span> <span class="nn">RNS</span>
<span class="kn">import</span> <span class="nn">RNS.vendor.umsgpack</span> <span class="k">as</span> <span class="nn">umsgpack</span>
<span class="c1"># Let&#39;s define an app name. We&#39;ll use this for all</span>
<span class="c1"># destinations we create. Since this echo example</span>
<span class="c1"># is part of a range of example utilities, we&#39;ll put</span>
<span class="c1"># them all within the app namespace &quot;example_utilities&quot;</span>
<span class="n">APP_NAME</span> <span class="o">=</span> <span class="s2">&quot;example_utilities&quot;</span>
<span class="c1"># We&#39;ll also define a default timeout, in seconds</span>
<span class="n">APP_TIMEOUT</span> <span class="o">=</span> <span class="mf">45.0</span>
<span class="c1">##########################################################</span>
<span class="c1">#### Server Part #########################################</span>
<span class="c1">##########################################################</span>
<span class="n">serve_path</span> <span class="o">=</span> <span class="kc">None</span>
<span class="c1"># This initialisation is executed when the users chooses</span>
<span class="c1"># to run as a server</span>
<span class="k">def</span> <span class="nf">server</span><span class="p">(</span><span class="n">configpath</span><span class="p">,</span> <span class="n">path</span><span class="p">):</span>
<span class="c1"># We must first initialise Reticulum</span>
<span class="n">reticulum</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Reticulum</span><span class="p">(</span><span class="n">configpath</span><span class="p">)</span>
<span class="c1"># Randomly create a new identity for our file server</span>
<span class="n">server_identity</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Identity</span><span class="p">()</span>
<span class="k">global</span> <span class="n">serve_path</span>
<span class="n">serve_path</span> <span class="o">=</span> <span class="n">path</span>
<span class="c1"># We create a destination that clients can connect to. We</span>
<span class="c1"># want clients to create links to this destination, so we</span>
<span class="c1"># need to create a &quot;single&quot; destination type.</span>
<span class="n">server_destination</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="p">(</span>
<span class="n">server_identity</span><span class="p">,</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">IN</span><span class="p">,</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">SINGLE</span><span class="p">,</span>
<span class="n">APP_NAME</span><span class="p">,</span>
<span class="s2">&quot;filetransfer&quot;</span><span class="p">,</span>
<span class="s2">&quot;server&quot;</span>
<span class="p">)</span>
<span class="c1"># We configure a function that will get called every time</span>
<span class="c1"># a new client creates a link to this destination.</span>
<span class="n">server_destination</span><span class="o">.</span><span class="n">set_link_established_callback</span><span class="p">(</span><span class="n">client_connected</span><span class="p">)</span>
<span class="c1"># Everything&#39;s ready!</span>
<span class="c1"># Let&#39;s Wait for client requests or user input</span>
<span class="n">announceLoop</span><span class="p">(</span><span class="n">server_destination</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">announceLoop</span><span class="p">(</span><span class="n">destination</span><span class="p">):</span>
<span class="c1"># Let the user know that everything is ready</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;File server &quot;</span><span class="o">+</span><span class="n">RNS</span><span class="o">.</span><span class="n">prettyhexrep</span><span class="p">(</span><span class="n">destination</span><span class="o">.</span><span class="n">hash</span><span class="p">)</span><span class="o">+</span><span class="s2">&quot; running&quot;</span><span class="p">)</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Hit enter to manually send an announce (Ctrl-C to quit)&quot;</span><span class="p">)</span>
<span class="c1"># We enter a loop that runs until the users exits.</span>
<span class="c1"># If the user hits enter, we will announce our server</span>
<span class="c1"># destination on the network, which will let clients</span>
<span class="c1"># know how to create messages directed towards it.</span>
<span class="k">while</span> <span class="kc">True</span><span class="p">:</span>
<span class="n">entered</span> <span class="o">=</span> <span class="nb">input</span><span class="p">()</span>
<span class="n">destination</span><span class="o">.</span><span class="n">announce</span><span class="p">()</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Sent announce from &quot;</span><span class="o">+</span><span class="n">RNS</span><span class="o">.</span><span class="n">prettyhexrep</span><span class="p">(</span><span class="n">destination</span><span class="o">.</span><span class="n">hash</span><span class="p">))</span>
<span class="c1"># Here&#39;s a convenience function for listing all files</span>
<span class="c1"># in our served directory</span>
<span class="k">def</span> <span class="nf">list_files</span><span class="p">():</span>
<span class="c1"># We add all entries from the directory that are</span>
<span class="c1"># actual files, and does not start with &quot;.&quot;</span>
<span class="k">global</span> <span class="n">serve_path</span>
<span class="k">return</span> <span class="p">[</span><span class="n">file</span> <span class="k">for</span> <span class="n">file</span> <span class="ow">in</span> <span class="n">os</span><span class="o">.</span><span class="n">listdir</span><span class="p">(</span><span class="n">serve_path</span><span class="p">)</span> <span class="k">if</span> <span class="n">os</span><span class="o">.</span><span class="n">path</span><span class="o">.</span><span class="n">isfile</span><span class="p">(</span><span class="n">os</span><span class="o">.</span><span class="n">path</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="n">serve_path</span><span class="p">,</span> <span class="n">file</span><span class="p">))</span> <span class="ow">and</span> <span class="n">file</span><span class="p">[:</span><span class="mi">1</span><span class="p">]</span> <span class="o">!=</span> <span class="s2">&quot;.&quot;</span><span class="p">]</span>
<span class="c1"># When a client establishes a link to our server</span>
<span class="c1"># destination, this function will be called with</span>
<span class="c1"># a reference to the link. We then send the client</span>
<span class="c1"># a list of files hosted on the server.</span>
<span class="k">def</span> <span class="nf">client_connected</span><span class="p">(</span><span class="n">link</span><span class="p">):</span>
<span class="c1"># Check if the served directory still exists</span>
<span class="k">if</span> <span class="n">os</span><span class="o">.</span><span class="n">path</span><span class="o">.</span><span class="n">isdir</span><span class="p">(</span><span class="n">serve_path</span><span class="p">):</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Client connected, sending file list...&quot;</span><span class="p">)</span>
<span class="n">link</span><span class="o">.</span><span class="n">set_link_closed_callback</span><span class="p">(</span><span class="n">client_disconnected</span><span class="p">)</span>
<span class="c1"># We pack a list of files for sending in a packet</span>
<span class="n">data</span> <span class="o">=</span> <span class="n">umsgpack</span><span class="o">.</span><span class="n">packb</span><span class="p">(</span><span class="n">list_files</span><span class="p">())</span>
<span class="c1"># Check the size of the packed data</span>
<span class="k">if</span> <span class="nb">len</span><span class="p">(</span><span class="n">data</span><span class="p">)</span> <span class="o">&lt;=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Link</span><span class="o">.</span><span class="n">MDU</span><span class="p">:</span>
<span class="c1"># If it fits in one packet, we will just</span>
<span class="c1"># send it as a single packet over the link.</span>
<span class="n">list_packet</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Packet</span><span class="p">(</span><span class="n">link</span><span class="p">,</span> <span class="n">data</span><span class="p">)</span>
<span class="n">list_receipt</span> <span class="o">=</span> <span class="n">list_packet</span><span class="o">.</span><span class="n">send</span><span class="p">()</span>
<span class="n">list_receipt</span><span class="o">.</span><span class="n">set_timeout</span><span class="p">(</span><span class="n">APP_TIMEOUT</span><span class="p">)</span>
<span class="n">list_receipt</span><span class="o">.</span><span class="n">set_delivery_callback</span><span class="p">(</span><span class="n">list_delivered</span><span class="p">)</span>
<span class="n">list_receipt</span><span class="o">.</span><span class="n">set_timeout_callback</span><span class="p">(</span><span class="n">list_timeout</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Too many files in served directory!&quot;</span><span class="p">,</span> <span class="n">RNS</span><span class="o">.</span><span class="n">LOG_ERROR</span><span class="p">)</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;You should implement a function to split the filelist over multiple packets.&quot;</span><span class="p">,</span> <span class="n">RNS</span><span class="o">.</span><span class="n">LOG_ERROR</span><span class="p">)</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Hint: The client already supports it :)&quot;</span><span class="p">,</span> <span class="n">RNS</span><span class="o">.</span><span class="n">LOG_ERROR</span><span class="p">)</span>
<span class="c1"># After this, we&#39;re just going to keep the link</span>
<span class="c1"># open until the client requests a file. We&#39;ll</span>
<span class="c1"># configure a function that get&#39;s called when</span>
<span class="c1"># the client sends a packet with a file request.</span>
<span class="n">link</span><span class="o">.</span><span class="n">set_packet_callback</span><span class="p">(</span><span class="n">client_request</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Client connected, but served path no longer exists!&quot;</span><span class="p">,</span> <span class="n">RNS</span><span class="o">.</span><span class="n">LOG_ERROR</span><span class="p">)</span>
<span class="n">link</span><span class="o">.</span><span class="n">teardown</span><span class="p">()</span>
<span class="k">def</span> <span class="nf">client_disconnected</span><span class="p">(</span><span class="n">link</span><span class="p">):</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Client disconnected&quot;</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">client_request</span><span class="p">(</span><span class="n">message</span><span class="p">,</span> <span class="n">packet</span><span class="p">):</span>
<span class="k">global</span> <span class="n">serve_path</span>
<span class="k">try</span><span class="p">:</span>
<span class="n">filename</span> <span class="o">=</span> <span class="n">message</span><span class="o">.</span><span class="n">decode</span><span class="p">(</span><span class="s2">&quot;utf-8&quot;</span><span class="p">)</span>
<span class="k">except</span> <span class="ne">Exception</span> <span class="k">as</span> <span class="n">e</span><span class="p">:</span>
<span class="n">filename</span> <span class="o">=</span> <span class="kc">None</span>
<span class="k">if</span> <span class="n">filename</span> <span class="ow">in</span> <span class="n">list_files</span><span class="p">():</span>
<span class="k">try</span><span class="p">:</span>
<span class="c1"># If we have the requested file, we&#39;ll</span>
<span class="c1"># read it and pack it as a resource</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Client requested </span><span class="se">\&quot;</span><span class="s2">&quot;</span><span class="o">+</span><span class="n">filename</span><span class="o">+</span><span class="s2">&quot;</span><span class="se">\&quot;</span><span class="s2">&quot;</span><span class="p">)</span>
<span class="n">file</span> <span class="o">=</span> <span class="nb">open</span><span class="p">(</span><span class="n">os</span><span class="o">.</span><span class="n">path</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="n">serve_path</span><span class="p">,</span> <span class="n">filename</span><span class="p">),</span> <span class="s2">&quot;rb&quot;</span><span class="p">)</span>
<span class="n">file_resource</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Resource</span><span class="p">(</span>
<span class="n">file</span><span class="p">,</span>
<span class="n">packet</span><span class="o">.</span><span class="n">link</span><span class="p">,</span>
<span class="n">callback</span><span class="o">=</span><span class="n">resource_sending_concluded</span>
<span class="p">)</span>
<span class="n">file_resource</span><span class="o">.</span><span class="n">filename</span> <span class="o">=</span> <span class="n">filename</span>
<span class="k">except</span> <span class="ne">Exception</span> <span class="k">as</span> <span class="n">e</span><span class="p">:</span>
<span class="c1"># If somethign went wrong, we close</span>
<span class="c1"># the link</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Error while reading file </span><span class="se">\&quot;</span><span class="s2">&quot;</span><span class="o">+</span><span class="n">filename</span><span class="o">+</span><span class="s2">&quot;</span><span class="se">\&quot;</span><span class="s2">&quot;</span><span class="p">,</span> <span class="n">RNS</span><span class="o">.</span><span class="n">LOG_ERROR</span><span class="p">)</span>
<span class="n">packet</span><span class="o">.</span><span class="n">link</span><span class="o">.</span><span class="n">teardown</span><span class="p">()</span>
<span class="k">raise</span> <span class="n">e</span>
<span class="k">else</span><span class="p">:</span>
<span class="c1"># If we don&#39;t have it, we close the link</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Client requested an unknown file&quot;</span><span class="p">)</span>
<span class="n">packet</span><span class="o">.</span><span class="n">link</span><span class="o">.</span><span class="n">teardown</span><span class="p">()</span>
<span class="c1"># This function is called on the server when a</span>
<span class="c1"># resource transfer concludes.</span>
<span class="k">def</span> <span class="nf">resource_sending_concluded</span><span class="p">(</span><span class="n">resource</span><span class="p">):</span>
<span class="k">if</span> <span class="nb">hasattr</span><span class="p">(</span><span class="n">resource</span><span class="p">,</span> <span class="s2">&quot;filename&quot;</span><span class="p">):</span>
<span class="n">name</span> <span class="o">=</span> <span class="n">resource</span><span class="o">.</span><span class="n">filename</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">name</span> <span class="o">=</span> <span class="s2">&quot;resource&quot;</span>
<span class="k">if</span> <span class="n">resource</span><span class="o">.</span><span class="n">status</span> <span class="o">==</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Resource</span><span class="o">.</span><span class="n">COMPLETE</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Done sending </span><span class="se">\&quot;</span><span class="s2">&quot;</span><span class="o">+</span><span class="n">name</span><span class="o">+</span><span class="s2">&quot;</span><span class="se">\&quot;</span><span class="s2"> to client&quot;</span><span class="p">)</span>
<span class="k">elif</span> <span class="n">resource</span><span class="o">.</span><span class="n">status</span> <span class="o">==</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Resource</span><span class="o">.</span><span class="n">FAILED</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Sending </span><span class="se">\&quot;</span><span class="s2">&quot;</span><span class="o">+</span><span class="n">name</span><span class="o">+</span><span class="s2">&quot;</span><span class="se">\&quot;</span><span class="s2"> to client failed&quot;</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">list_delivered</span><span class="p">(</span><span class="n">receipt</span><span class="p">):</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;The file list was received by the client&quot;</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">list_timeout</span><span class="p">(</span><span class="n">receipt</span><span class="p">):</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Sending list to client timed out, closing this link&quot;</span><span class="p">)</span>
<span class="n">link</span> <span class="o">=</span> <span class="n">receipt</span><span class="o">.</span><span class="n">destination</span>
<span class="n">link</span><span class="o">.</span><span class="n">teardown</span><span class="p">()</span>
<span class="c1">##########################################################</span>
<span class="c1">#### Client Part #########################################</span>
<span class="c1">##########################################################</span>
<span class="c1"># We store a global list of files available on the server</span>
<span class="n">server_files</span> <span class="o">=</span> <span class="p">[]</span>
<span class="c1"># A reference to the server link</span>
<span class="n">server_link</span> <span class="o">=</span> <span class="kc">None</span>
<span class="c1"># And a reference to the current download</span>
<span class="n">current_download</span> <span class="o">=</span> <span class="kc">None</span>
<span class="n">current_filename</span> <span class="o">=</span> <span class="kc">None</span>
<span class="c1"># Variables to store download statistics</span>
<span class="n">download_started</span> <span class="o">=</span> <span class="mi">0</span>
<span class="n">download_finished</span> <span class="o">=</span> <span class="mi">0</span>
<span class="n">download_time</span> <span class="o">=</span> <span class="mi">0</span>
<span class="n">transfer_size</span> <span class="o">=</span> <span class="mi">0</span>
<span class="n">file_size</span> <span class="o">=</span> <span class="mi">0</span>
<span class="c1"># This initialisation is executed when the users chooses</span>
<span class="c1"># to run as a client</span>
<span class="k">def</span> <span class="nf">client</span><span class="p">(</span><span class="n">destination_hexhash</span><span class="p">,</span> <span class="n">configpath</span><span class="p">):</span>
<span class="c1"># We need a binary representation of the destination</span>
<span class="c1"># hash that was entered on the command line</span>
<span class="k">try</span><span class="p">:</span>
<span class="k">if</span> <span class="nb">len</span><span class="p">(</span><span class="n">destination_hexhash</span><span class="p">)</span> <span class="o">!=</span> <span class="mi">20</span><span class="p">:</span>
<span class="k">raise</span> <span class="ne">ValueError</span><span class="p">(</span><span class="s2">&quot;Destination length is invalid, must be 20 hexadecimal characters (10 bytes)&quot;</span><span class="p">)</span>
<span class="n">destination_hash</span> <span class="o">=</span> <span class="nb">bytes</span><span class="o">.</span><span class="n">fromhex</span><span class="p">(</span><span class="n">destination_hexhash</span><span class="p">)</span>
<span class="k">except</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Invalid destination entered. Check your input!</span><span class="se">\n</span><span class="s2">&quot;</span><span class="p">)</span>
<span class="n">exit</span><span class="p">()</span>
<span class="c1"># We must first initialise Reticulum</span>
<span class="n">reticulum</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Reticulum</span><span class="p">(</span><span class="n">configpath</span><span class="p">)</span>
<span class="c1"># Check if we know a path to the destination</span>
<span class="k">if</span> <span class="ow">not</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Transport</span><span class="o">.</span><span class="n">has_path</span><span class="p">(</span><span class="n">destination_hash</span><span class="p">):</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Destination is not yet known. Requesting path and waiting for announce to arrive...&quot;</span><span class="p">)</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Transport</span><span class="o">.</span><span class="n">request_path</span><span class="p">(</span><span class="n">destination_hash</span><span class="p">)</span>
<span class="k">while</span> <span class="ow">not</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Transport</span><span class="o">.</span><span class="n">has_path</span><span class="p">(</span><span class="n">destination_hash</span><span class="p">):</span>
<span class="n">time</span><span class="o">.</span><span class="n">sleep</span><span class="p">(</span><span class="mf">0.1</span><span class="p">)</span>
<span class="c1"># Recall the server identity</span>
<span class="n">server_identity</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Identity</span><span class="o">.</span><span class="n">recall</span><span class="p">(</span><span class="n">destination_hash</span><span class="p">)</span>
<span class="c1"># Inform the user that we&#39;ll begin connecting</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Establishing link with server...&quot;</span><span class="p">)</span>
<span class="c1"># When the server identity is known, we set</span>
<span class="c1"># up a destination</span>
<span class="n">server_destination</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="p">(</span>
<span class="n">server_identity</span><span class="p">,</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">OUT</span><span class="p">,</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">SINGLE</span><span class="p">,</span>
<span class="n">APP_NAME</span><span class="p">,</span>
<span class="s2">&quot;filetransfer&quot;</span><span class="p">,</span>
<span class="s2">&quot;server&quot;</span>
<span class="p">)</span>
<span class="c1"># We also want to automatically prove incoming packets</span>
<span class="n">server_destination</span><span class="o">.</span><span class="n">set_proof_strategy</span><span class="p">(</span><span class="n">RNS</span><span class="o">.</span><span class="n">Destination</span><span class="o">.</span><span class="n">PROVE_ALL</span><span class="p">)</span>
<span class="c1"># And create a link</span>
<span class="n">link</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Link</span><span class="p">(</span><span class="n">server_destination</span><span class="p">)</span>
<span class="c1"># We expect any normal data packets on the link</span>
<span class="c1"># to contain a list of served files, so we set</span>
<span class="c1"># a callback accordingly</span>
<span class="n">link</span><span class="o">.</span><span class="n">set_packet_callback</span><span class="p">(</span><span class="n">filelist_received</span><span class="p">)</span>
<span class="c1"># We&#39;ll also set up functions to inform the</span>
<span class="c1"># user when the link is established or closed</span>
<span class="n">link</span><span class="o">.</span><span class="n">set_link_established_callback</span><span class="p">(</span><span class="n">link_established</span><span class="p">)</span>
<span class="n">link</span><span class="o">.</span><span class="n">set_link_closed_callback</span><span class="p">(</span><span class="n">link_closed</span><span class="p">)</span>
<span class="c1"># And set the link to automatically begin</span>
<span class="c1"># downloading advertised resources</span>
<span class="n">link</span><span class="o">.</span><span class="n">set_resource_strategy</span><span class="p">(</span><span class="n">RNS</span><span class="o">.</span><span class="n">Link</span><span class="o">.</span><span class="n">ACCEPT_ALL</span><span class="p">)</span>
<span class="n">link</span><span class="o">.</span><span class="n">set_resource_started_callback</span><span class="p">(</span><span class="n">download_began</span><span class="p">)</span>
<span class="n">link</span><span class="o">.</span><span class="n">set_resource_concluded_callback</span><span class="p">(</span><span class="n">download_concluded</span><span class="p">)</span>
<span class="n">menu</span><span class="p">()</span>
<span class="c1"># Requests the specified file from the server</span>
<span class="k">def</span> <span class="nf">download</span><span class="p">(</span><span class="n">filename</span><span class="p">):</span>
<span class="k">global</span> <span class="n">server_link</span><span class="p">,</span> <span class="n">menu_mode</span><span class="p">,</span> <span class="n">current_filename</span><span class="p">,</span> <span class="n">transfer_size</span><span class="p">,</span> <span class="n">download_started</span>
<span class="n">current_filename</span> <span class="o">=</span> <span class="n">filename</span>
<span class="n">download_started</span> <span class="o">=</span> <span class="mi">0</span>
<span class="n">transfer_size</span> <span class="o">=</span> <span class="mi">0</span>
<span class="c1"># We just create a packet containing the</span>
<span class="c1"># requested filename, and send it down the</span>
<span class="c1"># link. We also specify we don&#39;t need a</span>
<span class="c1"># packet receipt.</span>
<span class="n">request_packet</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Packet</span><span class="p">(</span><span class="n">server_link</span><span class="p">,</span> <span class="n">filename</span><span class="o">.</span><span class="n">encode</span><span class="p">(</span><span class="s2">&quot;utf-8&quot;</span><span class="p">),</span> <span class="n">create_receipt</span><span class="o">=</span><span class="kc">False</span><span class="p">)</span>
<span class="n">request_packet</span><span class="o">.</span><span class="n">send</span><span class="p">()</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="nb">print</span><span class="p">((</span><span class="s2">&quot;Requested </span><span class="se">\&quot;</span><span class="s2">&quot;</span><span class="o">+</span><span class="n">filename</span><span class="o">+</span><span class="s2">&quot;</span><span class="se">\&quot;</span><span class="s2"> from server, waiting for download to begin...&quot;</span><span class="p">))</span>
<span class="n">menu_mode</span> <span class="o">=</span> <span class="s2">&quot;download_started&quot;</span>
<span class="c1"># This function runs a simple menu for the user</span>
<span class="c1"># to select which files to download, or quit</span>
<span class="n">menu_mode</span> <span class="o">=</span> <span class="kc">None</span>
<span class="k">def</span> <span class="nf">menu</span><span class="p">():</span>
<span class="k">global</span> <span class="n">server_files</span><span class="p">,</span> <span class="n">server_link</span>
<span class="c1"># Wait until we have a filelist</span>
<span class="k">while</span> <span class="nb">len</span><span class="p">(</span><span class="n">server_files</span><span class="p">)</span> <span class="o">==</span> <span class="mi">0</span><span class="p">:</span>
<span class="n">time</span><span class="o">.</span><span class="n">sleep</span><span class="p">(</span><span class="mf">0.1</span><span class="p">)</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Ready!&quot;</span><span class="p">)</span>
<span class="n">time</span><span class="o">.</span><span class="n">sleep</span><span class="p">(</span><span class="mf">0.5</span><span class="p">)</span>
<span class="k">global</span> <span class="n">menu_mode</span>
<span class="n">menu_mode</span> <span class="o">=</span> <span class="s2">&quot;main&quot;</span>
<span class="n">should_quit</span> <span class="o">=</span> <span class="kc">False</span>
<span class="k">while</span> <span class="p">(</span><span class="ow">not</span> <span class="n">should_quit</span><span class="p">):</span>
<span class="n">print_menu</span><span class="p">()</span>
<span class="k">while</span> <span class="ow">not</span> <span class="n">menu_mode</span> <span class="o">==</span> <span class="s2">&quot;main&quot;</span><span class="p">:</span>
<span class="c1"># Wait</span>
<span class="n">time</span><span class="o">.</span><span class="n">sleep</span><span class="p">(</span><span class="mf">0.25</span><span class="p">)</span>
<span class="n">user_input</span> <span class="o">=</span> <span class="nb">input</span><span class="p">()</span>
<span class="k">if</span> <span class="n">user_input</span> <span class="o">==</span> <span class="s2">&quot;q&quot;</span> <span class="ow">or</span> <span class="n">user_input</span> <span class="o">==</span> <span class="s2">&quot;quit&quot;</span> <span class="ow">or</span> <span class="n">user_input</span> <span class="o">==</span> <span class="s2">&quot;exit&quot;</span><span class="p">:</span>
<span class="n">should_quit</span> <span class="o">=</span> <span class="kc">True</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="k">if</span> <span class="n">user_input</span> <span class="ow">in</span> <span class="n">server_files</span><span class="p">:</span>
<span class="n">download</span><span class="p">(</span><span class="n">user_input</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="k">try</span><span class="p">:</span>
<span class="k">if</span> <span class="mi">0</span> <span class="o">&lt;=</span> <span class="nb">int</span><span class="p">(</span><span class="n">user_input</span><span class="p">)</span> <span class="o">&lt;</span> <span class="nb">len</span><span class="p">(</span><span class="n">server_files</span><span class="p">):</span>
<span class="n">download</span><span class="p">(</span><span class="n">server_files</span><span class="p">[</span><span class="nb">int</span><span class="p">(</span><span class="n">user_input</span><span class="p">)])</span>
<span class="k">except</span><span class="p">:</span>
<span class="k">pass</span>
<span class="k">if</span> <span class="n">should_quit</span><span class="p">:</span>
<span class="n">server_link</span><span class="o">.</span><span class="n">teardown</span><span class="p">()</span>
<span class="c1"># Prints out menus or screens for the</span>
<span class="c1"># various states of the client program.</span>
<span class="c1"># It&#39;s simple and quite uninteresting.</span>
<span class="c1"># I won&#39;t go into detail here. Just</span>
<span class="c1"># strings basically.</span>
<span class="k">def</span> <span class="nf">print_menu</span><span class="p">():</span>
<span class="k">global</span> <span class="n">menu_mode</span><span class="p">,</span> <span class="n">download_time</span><span class="p">,</span> <span class="n">download_started</span><span class="p">,</span> <span class="n">download_finished</span><span class="p">,</span> <span class="n">transfer_size</span><span class="p">,</span> <span class="n">file_size</span>
<span class="k">if</span> <span class="n">menu_mode</span> <span class="o">==</span> <span class="s2">&quot;main&quot;</span><span class="p">:</span>
<span class="n">clear_screen</span><span class="p">()</span>
<span class="n">print_filelist</span><span class="p">()</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;Select a file to download by entering name or number, or q to quit&quot;</span><span class="p">)</span>
<span class="nb">print</span><span class="p">((</span><span class="s2">&quot;&gt; &quot;</span><span class="p">),</span> <span class="n">end</span><span class="o">=</span><span class="s1">&#39; &#39;</span><span class="p">)</span>
<span class="k">elif</span> <span class="n">menu_mode</span> <span class="o">==</span> <span class="s2">&quot;download_started&quot;</span><span class="p">:</span>
<span class="n">download_began</span> <span class="o">=</span> <span class="n">time</span><span class="o">.</span><span class="n">time</span><span class="p">()</span>
<span class="k">while</span> <span class="n">menu_mode</span> <span class="o">==</span> <span class="s2">&quot;download_started&quot;</span><span class="p">:</span>
<span class="n">time</span><span class="o">.</span><span class="n">sleep</span><span class="p">(</span><span class="mf">0.1</span><span class="p">)</span>
<span class="k">if</span> <span class="n">time</span><span class="o">.</span><span class="n">time</span><span class="p">()</span> <span class="o">&gt;</span> <span class="n">download_began</span><span class="o">+</span><span class="n">APP_TIMEOUT</span><span class="p">:</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;The download timed out&quot;</span><span class="p">)</span>
<span class="n">time</span><span class="o">.</span><span class="n">sleep</span><span class="p">(</span><span class="mi">1</span><span class="p">)</span>
<span class="n">server_link</span><span class="o">.</span><span class="n">teardown</span><span class="p">()</span>
<span class="k">if</span> <span class="n">menu_mode</span> <span class="o">==</span> <span class="s2">&quot;downloading&quot;</span><span class="p">:</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;Download started&quot;</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="k">while</span> <span class="n">menu_mode</span> <span class="o">==</span> <span class="s2">&quot;downloading&quot;</span><span class="p">:</span>
<span class="k">global</span> <span class="n">current_download</span>
<span class="n">percent</span> <span class="o">=</span> <span class="nb">round</span><span class="p">(</span><span class="n">current_download</span><span class="o">.</span><span class="n">get_progress</span><span class="p">()</span> <span class="o">*</span> <span class="mf">100.0</span><span class="p">,</span> <span class="mi">1</span><span class="p">)</span>
<span class="nb">print</span><span class="p">((</span><span class="s2">&quot;</span><span class="se">\r</span><span class="s2">Progress: &quot;</span><span class="o">+</span><span class="nb">str</span><span class="p">(</span><span class="n">percent</span><span class="p">)</span><span class="o">+</span><span class="s2">&quot; % &quot;</span><span class="p">),</span> <span class="n">end</span><span class="o">=</span><span class="s1">&#39; &#39;</span><span class="p">)</span>
<span class="n">sys</span><span class="o">.</span><span class="n">stdout</span><span class="o">.</span><span class="n">flush</span><span class="p">()</span>
<span class="n">time</span><span class="o">.</span><span class="n">sleep</span><span class="p">(</span><span class="mf">0.1</span><span class="p">)</span>
<span class="k">if</span> <span class="n">menu_mode</span> <span class="o">==</span> <span class="s2">&quot;save_error&quot;</span><span class="p">:</span>
<span class="nb">print</span><span class="p">((</span><span class="s2">&quot;</span><span class="se">\r</span><span class="s2">Progress: 100.0 %&quot;</span><span class="p">),</span> <span class="n">end</span><span class="o">=</span><span class="s1">&#39; &#39;</span><span class="p">)</span>
<span class="n">sys</span><span class="o">.</span><span class="n">stdout</span><span class="o">.</span><span class="n">flush</span><span class="p">()</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;Could not write downloaded file to disk&quot;</span><span class="p">)</span>
<span class="n">current_download</span><span class="o">.</span><span class="n">status</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Resource</span><span class="o">.</span><span class="n">FAILED</span>
<span class="n">menu_mode</span> <span class="o">=</span> <span class="s2">&quot;download_concluded&quot;</span>
<span class="k">if</span> <span class="n">menu_mode</span> <span class="o">==</span> <span class="s2">&quot;download_concluded&quot;</span><span class="p">:</span>
<span class="k">if</span> <span class="n">current_download</span><span class="o">.</span><span class="n">status</span> <span class="o">==</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Resource</span><span class="o">.</span><span class="n">COMPLETE</span><span class="p">:</span>
<span class="nb">print</span><span class="p">((</span><span class="s2">&quot;</span><span class="se">\r</span><span class="s2">Progress: 100.0 %&quot;</span><span class="p">),</span> <span class="n">end</span><span class="o">=</span><span class="s1">&#39; &#39;</span><span class="p">)</span>
<span class="n">sys</span><span class="o">.</span><span class="n">stdout</span><span class="o">.</span><span class="n">flush</span><span class="p">()</span>
<span class="c1"># Print statistics</span>
<span class="n">hours</span><span class="p">,</span> <span class="n">rem</span> <span class="o">=</span> <span class="nb">divmod</span><span class="p">(</span><span class="n">download_time</span><span class="p">,</span> <span class="mi">3600</span><span class="p">)</span>
<span class="n">minutes</span><span class="p">,</span> <span class="n">seconds</span> <span class="o">=</span> <span class="nb">divmod</span><span class="p">(</span><span class="n">rem</span><span class="p">,</span> <span class="mi">60</span><span class="p">)</span>
<span class="n">timestring</span> <span class="o">=</span> <span class="s2">&quot;</span><span class="si">{:0&gt;2}</span><span class="s2">:</span><span class="si">{:0&gt;2}</span><span class="s2">:</span><span class="si">{:05.2f}</span><span class="s2">&quot;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="nb">int</span><span class="p">(</span><span class="n">hours</span><span class="p">),</span><span class="nb">int</span><span class="p">(</span><span class="n">minutes</span><span class="p">),</span><span class="n">seconds</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;--- Statistics -----&quot;</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;</span><span class="se">\t</span><span class="s2">Time taken : &quot;</span><span class="o">+</span><span class="n">timestring</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;</span><span class="se">\t</span><span class="s2">File size : &quot;</span><span class="o">+</span><span class="n">size_str</span><span class="p">(</span><span class="n">file_size</span><span class="p">))</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;</span><span class="se">\t</span><span class="s2">Data transferred : &quot;</span><span class="o">+</span><span class="n">size_str</span><span class="p">(</span><span class="n">transfer_size</span><span class="p">))</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;</span><span class="se">\t</span><span class="s2">Effective rate : &quot;</span><span class="o">+</span><span class="n">size_str</span><span class="p">(</span><span class="n">file_size</span><span class="o">/</span><span class="n">download_time</span><span class="p">,</span> <span class="n">suffix</span><span class="o">=</span><span class="s1">&#39;b&#39;</span><span class="p">)</span><span class="o">+</span><span class="s2">&quot;/s&quot;</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;</span><span class="se">\t</span><span class="s2">Transfer rate : &quot;</span><span class="o">+</span><span class="n">size_str</span><span class="p">(</span><span class="n">transfer_size</span><span class="o">/</span><span class="n">download_time</span><span class="p">,</span> <span class="n">suffix</span><span class="o">=</span><span class="s1">&#39;b&#39;</span><span class="p">)</span><span class="o">+</span><span class="s2">&quot;/s&quot;</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;The download completed! Press enter to return to the menu.&quot;</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="nb">input</span><span class="p">()</span>
<span class="k">else</span><span class="p">:</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;The download failed! Press enter to return to the menu.&quot;</span><span class="p">)</span>
<span class="nb">input</span><span class="p">()</span>
<span class="n">current_download</span> <span class="o">=</span> <span class="kc">None</span>
<span class="n">menu_mode</span> <span class="o">=</span> <span class="s2">&quot;main&quot;</span>
<span class="n">print_menu</span><span class="p">()</span>
<span class="c1"># This function prints out a list of files</span>
<span class="c1"># on the connected server.</span>
<span class="k">def</span> <span class="nf">print_filelist</span><span class="p">():</span>
<span class="k">global</span> <span class="n">server_files</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;Files on server:&quot;</span><span class="p">)</span>
<span class="k">for</span> <span class="n">index</span><span class="p">,</span><span class="n">file</span> <span class="ow">in</span> <span class="nb">enumerate</span><span class="p">(</span><span class="n">server_files</span><span class="p">):</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;</span><span class="se">\t</span><span class="s2">(&quot;</span><span class="o">+</span><span class="nb">str</span><span class="p">(</span><span class="n">index</span><span class="p">)</span><span class="o">+</span><span class="s2">&quot;)</span><span class="se">\t</span><span class="s2">&quot;</span><span class="o">+</span><span class="n">file</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">filelist_received</span><span class="p">(</span><span class="n">filelist_data</span><span class="p">,</span> <span class="n">packet</span><span class="p">):</span>
<span class="k">global</span> <span class="n">server_files</span><span class="p">,</span> <span class="n">menu_mode</span>
<span class="k">try</span><span class="p">:</span>
<span class="c1"># Unpack the list and extend our</span>
<span class="c1"># local list of available files</span>
<span class="n">filelist</span> <span class="o">=</span> <span class="n">umsgpack</span><span class="o">.</span><span class="n">unpackb</span><span class="p">(</span><span class="n">filelist_data</span><span class="p">)</span>
<span class="k">for</span> <span class="n">file</span> <span class="ow">in</span> <span class="n">filelist</span><span class="p">:</span>
<span class="k">if</span> <span class="ow">not</span> <span class="n">file</span> <span class="ow">in</span> <span class="n">server_files</span><span class="p">:</span>
<span class="n">server_files</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">file</span><span class="p">)</span>
<span class="c1"># If the menu is already visible,</span>
<span class="c1"># we&#39;ll update it with what was</span>
<span class="c1"># just received</span>
<span class="k">if</span> <span class="n">menu_mode</span> <span class="o">==</span> <span class="s2">&quot;main&quot;</span><span class="p">:</span>
<span class="n">print_menu</span><span class="p">()</span>
<span class="k">except</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Invalid file list data received, closing link&quot;</span><span class="p">)</span>
<span class="n">packet</span><span class="o">.</span><span class="n">link</span><span class="o">.</span><span class="n">teardown</span><span class="p">()</span>
<span class="c1"># This function is called when a link</span>
<span class="c1"># has been established with the server</span>
<span class="k">def</span> <span class="nf">link_established</span><span class="p">(</span><span class="n">link</span><span class="p">):</span>
<span class="c1"># We store a reference to the link</span>
<span class="c1"># instance for later use</span>
<span class="k">global</span> <span class="n">server_link</span>
<span class="n">server_link</span> <span class="o">=</span> <span class="n">link</span>
<span class="c1"># Inform the user that the server is</span>
<span class="c1"># connected</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Link established with server&quot;</span><span class="p">)</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Waiting for filelist...&quot;</span><span class="p">)</span>
<span class="c1"># And set up a small job to check for</span>
<span class="c1"># a potential timeout in receiving the</span>
<span class="c1"># file list</span>
<span class="n">thread</span> <span class="o">=</span> <span class="n">threading</span><span class="o">.</span><span class="n">Thread</span><span class="p">(</span><span class="n">target</span><span class="o">=</span><span class="n">filelist_timeout_job</span><span class="p">)</span>
<span class="n">thread</span><span class="o">.</span><span class="n">setDaemon</span><span class="p">(</span><span class="kc">True</span><span class="p">)</span>
<span class="n">thread</span><span class="o">.</span><span class="n">start</span><span class="p">()</span>
<span class="c1"># This job just sleeps for the specified</span>
<span class="c1"># time, and then checks if the file list</span>
<span class="c1"># was received. If not, the program will</span>
<span class="c1"># exit.</span>
<span class="k">def</span> <span class="nf">filelist_timeout_job</span><span class="p">():</span>
<span class="n">time</span><span class="o">.</span><span class="n">sleep</span><span class="p">(</span><span class="n">APP_TIMEOUT</span><span class="p">)</span>
<span class="k">global</span> <span class="n">server_files</span>
<span class="k">if</span> <span class="nb">len</span><span class="p">(</span><span class="n">server_files</span><span class="p">)</span> <span class="o">==</span> <span class="mi">0</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Timed out waiting for filelist, exiting&quot;</span><span class="p">)</span>
<span class="n">os</span><span class="o">.</span><span class="n">_exit</span><span class="p">(</span><span class="mi">0</span><span class="p">)</span>
<span class="c1"># When a link is closed, we&#39;ll inform the</span>
<span class="c1"># user, and exit the program</span>
<span class="k">def</span> <span class="nf">link_closed</span><span class="p">(</span><span class="n">link</span><span class="p">):</span>
<span class="k">if</span> <span class="n">link</span><span class="o">.</span><span class="n">teardown_reason</span> <span class="o">==</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Link</span><span class="o">.</span><span class="n">TIMEOUT</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;The link timed out, exiting now&quot;</span><span class="p">)</span>
<span class="k">elif</span> <span class="n">link</span><span class="o">.</span><span class="n">teardown_reason</span> <span class="o">==</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Link</span><span class="o">.</span><span class="n">DESTINATION_CLOSED</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;The link was closed by the server, exiting now&quot;</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Link closed, exiting now&quot;</span><span class="p">)</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">Reticulum</span><span class="o">.</span><span class="n">exit_handler</span><span class="p">()</span>
<span class="n">time</span><span class="o">.</span><span class="n">sleep</span><span class="p">(</span><span class="mf">1.5</span><span class="p">)</span>
<span class="n">os</span><span class="o">.</span><span class="n">_exit</span><span class="p">(</span><span class="mi">0</span><span class="p">)</span>
<span class="c1"># When RNS detects that the download has</span>
<span class="c1"># started, we&#39;ll update our menu state</span>
<span class="c1"># so the user can be shown a progress of</span>
<span class="c1"># the download.</span>
<span class="k">def</span> <span class="nf">download_began</span><span class="p">(</span><span class="n">resource</span><span class="p">):</span>
<span class="k">global</span> <span class="n">menu_mode</span><span class="p">,</span> <span class="n">current_download</span><span class="p">,</span> <span class="n">download_started</span><span class="p">,</span> <span class="n">transfer_size</span><span class="p">,</span> <span class="n">file_size</span>
<span class="n">current_download</span> <span class="o">=</span> <span class="n">resource</span>
<span class="k">if</span> <span class="n">download_started</span> <span class="o">==</span> <span class="mi">0</span><span class="p">:</span>
<span class="n">download_started</span> <span class="o">=</span> <span class="n">time</span><span class="o">.</span><span class="n">time</span><span class="p">()</span>
<span class="n">transfer_size</span> <span class="o">+=</span> <span class="n">resource</span><span class="o">.</span><span class="n">size</span>
<span class="n">file_size</span> <span class="o">=</span> <span class="n">resource</span><span class="o">.</span><span class="n">total_size</span>
<span class="n">menu_mode</span> <span class="o">=</span> <span class="s2">&quot;downloading&quot;</span>
<span class="c1"># When the download concludes, successfully</span>
<span class="c1"># or not, we&#39;ll update our menu state and </span>
<span class="c1"># inform the user about how it all went.</span>
<span class="k">def</span> <span class="nf">download_concluded</span><span class="p">(</span><span class="n">resource</span><span class="p">):</span>
<span class="k">global</span> <span class="n">menu_mode</span><span class="p">,</span> <span class="n">current_filename</span><span class="p">,</span> <span class="n">download_started</span><span class="p">,</span> <span class="n">download_finished</span><span class="p">,</span> <span class="n">download_time</span>
<span class="n">download_finished</span> <span class="o">=</span> <span class="n">time</span><span class="o">.</span><span class="n">time</span><span class="p">()</span>
<span class="n">download_time</span> <span class="o">=</span> <span class="n">download_finished</span> <span class="o">-</span> <span class="n">download_started</span>
<span class="n">saved_filename</span> <span class="o">=</span> <span class="n">current_filename</span>
<span class="k">if</span> <span class="n">resource</span><span class="o">.</span><span class="n">status</span> <span class="o">==</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Resource</span><span class="o">.</span><span class="n">COMPLETE</span><span class="p">:</span>
<span class="n">counter</span> <span class="o">=</span> <span class="mi">0</span>
<span class="k">while</span> <span class="n">os</span><span class="o">.</span><span class="n">path</span><span class="o">.</span><span class="n">isfile</span><span class="p">(</span><span class="n">saved_filename</span><span class="p">):</span>
<span class="n">counter</span> <span class="o">+=</span> <span class="mi">1</span>
<span class="n">saved_filename</span> <span class="o">=</span> <span class="n">current_filename</span><span class="o">+</span><span class="s2">&quot;.&quot;</span><span class="o">+</span><span class="nb">str</span><span class="p">(</span><span class="n">counter</span><span class="p">)</span>
<span class="k">try</span><span class="p">:</span>
<span class="n">file</span> <span class="o">=</span> <span class="nb">open</span><span class="p">(</span><span class="n">saved_filename</span><span class="p">,</span> <span class="s2">&quot;wb&quot;</span><span class="p">)</span>
<span class="n">file</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="n">resource</span><span class="o">.</span><span class="n">data</span><span class="o">.</span><span class="n">read</span><span class="p">())</span>
<span class="n">file</span><span class="o">.</span><span class="n">close</span><span class="p">()</span>
<span class="n">menu_mode</span> <span class="o">=</span> <span class="s2">&quot;download_concluded&quot;</span>
<span class="k">except</span><span class="p">:</span>
<span class="n">menu_mode</span> <span class="o">=</span> <span class="s2">&quot;save_error&quot;</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">menu_mode</span> <span class="o">=</span> <span class="s2">&quot;download_concluded&quot;</span>
<span class="c1"># A convenience function for printing a human-</span>
<span class="c1"># readable file size</span>
<span class="k">def</span> <span class="nf">size_str</span><span class="p">(</span><span class="n">num</span><span class="p">,</span> <span class="n">suffix</span><span class="o">=</span><span class="s1">&#39;B&#39;</span><span class="p">):</span>
<span class="n">units</span> <span class="o">=</span> <span class="p">[</span><span class="s1">&#39;&#39;</span><span class="p">,</span><span class="s1">&#39;Ki&#39;</span><span class="p">,</span><span class="s1">&#39;Mi&#39;</span><span class="p">,</span><span class="s1">&#39;Gi&#39;</span><span class="p">,</span><span class="s1">&#39;Ti&#39;</span><span class="p">,</span><span class="s1">&#39;Pi&#39;</span><span class="p">,</span><span class="s1">&#39;Ei&#39;</span><span class="p">,</span><span class="s1">&#39;Zi&#39;</span><span class="p">]</span>
<span class="n">last_unit</span> <span class="o">=</span> <span class="s1">&#39;Yi&#39;</span>
<span class="k">if</span> <span class="n">suffix</span> <span class="o">==</span> <span class="s1">&#39;b&#39;</span><span class="p">:</span>
<span class="n">num</span> <span class="o">*=</span> <span class="mi">8</span>
<span class="n">units</span> <span class="o">=</span> <span class="p">[</span><span class="s1">&#39;&#39;</span><span class="p">,</span><span class="s1">&#39;K&#39;</span><span class="p">,</span><span class="s1">&#39;M&#39;</span><span class="p">,</span><span class="s1">&#39;G&#39;</span><span class="p">,</span><span class="s1">&#39;T&#39;</span><span class="p">,</span><span class="s1">&#39;P&#39;</span><span class="p">,</span><span class="s1">&#39;E&#39;</span><span class="p">,</span><span class="s1">&#39;Z&#39;</span><span class="p">]</span>
<span class="n">last_unit</span> <span class="o">=</span> <span class="s1">&#39;Y&#39;</span>
<span class="k">for</span> <span class="n">unit</span> <span class="ow">in</span> <span class="n">units</span><span class="p">:</span>
<span class="k">if</span> <span class="nb">abs</span><span class="p">(</span><span class="n">num</span><span class="p">)</span> <span class="o">&lt;</span> <span class="mf">1024.0</span><span class="p">:</span>
<span class="k">return</span> <span class="s2">&quot;</span><span class="si">%3.2f</span><span class="s2"> </span><span class="si">%s%s</span><span class="s2">&quot;</span> <span class="o">%</span> <span class="p">(</span><span class="n">num</span><span class="p">,</span> <span class="n">unit</span><span class="p">,</span> <span class="n">suffix</span><span class="p">)</span>
<span class="n">num</span> <span class="o">/=</span> <span class="mf">1024.0</span>
<span class="k">return</span> <span class="s2">&quot;</span><span class="si">%.2f</span><span class="s2"> </span><span class="si">%s%s</span><span class="s2">&quot;</span> <span class="o">%</span> <span class="p">(</span><span class="n">num</span><span class="p">,</span> <span class="n">last_unit</span><span class="p">,</span> <span class="n">suffix</span><span class="p">)</span>
<span class="c1"># A convenience function for clearing the screen</span>
<span class="k">def</span> <span class="nf">clear_screen</span><span class="p">():</span>
<span class="n">os</span><span class="o">.</span><span class="n">system</span><span class="p">(</span><span class="s1">&#39;cls&#39;</span> <span class="k">if</span> <span class="n">os</span><span class="o">.</span><span class="n">name</span><span class="o">==</span><span class="s1">&#39;nt&#39;</span> <span class="k">else</span> <span class="s1">&#39;clear&#39;</span><span class="p">)</span>
<span class="c1">##########################################################</span>
<span class="c1">#### Program Startup #####################################</span>
<span class="c1">##########################################################</span>
<span class="c1"># This part of the program runs at startup,</span>
<span class="c1"># and parses input of from the user, and then</span>
<span class="c1"># starts up the desired program mode.</span>
<span class="k">if</span> <span class="vm">__name__</span> <span class="o">==</span> <span class="s2">&quot;__main__&quot;</span><span class="p">:</span>
<span class="k">try</span><span class="p">:</span>
<span class="n">parser</span> <span class="o">=</span> <span class="n">argparse</span><span class="o">.</span><span class="n">ArgumentParser</span><span class="p">(</span>
<span class="n">description</span><span class="o">=</span><span class="s2">&quot;Simple file transfer server and client utility&quot;</span>
<span class="p">)</span>
<span class="n">parser</span><span class="o">.</span><span class="n">add_argument</span><span class="p">(</span>
<span class="s2">&quot;-s&quot;</span><span class="p">,</span>
<span class="s2">&quot;--serve&quot;</span><span class="p">,</span>
<span class="n">action</span><span class="o">=</span><span class="s2">&quot;store&quot;</span><span class="p">,</span>
<span class="n">metavar</span><span class="o">=</span><span class="s2">&quot;dir&quot;</span><span class="p">,</span>
<span class="n">help</span><span class="o">=</span><span class="s2">&quot;serve a directory of files to clients&quot;</span>
<span class="p">)</span>
<span class="n">parser</span><span class="o">.</span><span class="n">add_argument</span><span class="p">(</span>
<span class="s2">&quot;--config&quot;</span><span class="p">,</span>
<span class="n">action</span><span class="o">=</span><span class="s2">&quot;store&quot;</span><span class="p">,</span>
<span class="n">default</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span>
<span class="n">help</span><span class="o">=</span><span class="s2">&quot;path to alternative Reticulum config directory&quot;</span><span class="p">,</span>
<span class="nb">type</span><span class="o">=</span><span class="nb">str</span>
<span class="p">)</span>
<span class="n">parser</span><span class="o">.</span><span class="n">add_argument</span><span class="p">(</span>
<span class="s2">&quot;destination&quot;</span><span class="p">,</span>
<span class="n">nargs</span><span class="o">=</span><span class="s2">&quot;?&quot;</span><span class="p">,</span>
<span class="n">default</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span>
<span class="n">help</span><span class="o">=</span><span class="s2">&quot;hexadecimal hash of the server destination&quot;</span><span class="p">,</span>
<span class="nb">type</span><span class="o">=</span><span class="nb">str</span>
<span class="p">)</span>
<span class="n">args</span> <span class="o">=</span> <span class="n">parser</span><span class="o">.</span><span class="n">parse_args</span><span class="p">()</span>
<span class="k">if</span> <span class="n">args</span><span class="o">.</span><span class="n">config</span><span class="p">:</span>
<span class="n">configarg</span> <span class="o">=</span> <span class="n">args</span><span class="o">.</span><span class="n">config</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">configarg</span> <span class="o">=</span> <span class="kc">None</span>
<span class="k">if</span> <span class="n">args</span><span class="o">.</span><span class="n">serve</span><span class="p">:</span>
<span class="k">if</span> <span class="n">os</span><span class="o">.</span><span class="n">path</span><span class="o">.</span><span class="n">isdir</span><span class="p">(</span><span class="n">args</span><span class="o">.</span><span class="n">serve</span><span class="p">):</span>
<span class="n">server</span><span class="p">(</span><span class="n">configarg</span><span class="p">,</span> <span class="n">args</span><span class="o">.</span><span class="n">serve</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;The specified directory does not exist&quot;</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="k">if</span> <span class="p">(</span><span class="n">args</span><span class="o">.</span><span class="n">destination</span> <span class="o">==</span> <span class="kc">None</span><span class="p">):</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="n">parser</span><span class="o">.</span><span class="n">print_help</span><span class="p">()</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">client</span><span class="p">(</span><span class="n">args</span><span class="o">.</span><span class="n">destination</span><span class="p">,</span> <span class="n">configarg</span><span class="p">)</span>
<span class="k">except</span> <span class="ne">KeyboardInterrupt</span><span class="p">:</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
<span class="n">exit</span><span class="p">()</span>
</pre></div>
</div>
<p>This example can also be found at <a class="reference external" href="https://github.com/markqvist/Reticulum/blob/master/Examples/Filetransfer.py">https://github.com/markqvist/Reticulum/blob/master/Examples/Filetransfer.py</a>.</p>
</div>
</div>
<div class="clearer"></div>
</div>
</div>
</div>
<div class="sphinxsidebar" role="navigation" aria-label="main navigation">
<div class="sphinxsidebarwrapper">
<h3><a href="index.html">Table of Contents</a></h3>
<ul>
<li><a class="reference internal" href="#">Code Examples</a><ul>
<li><a class="reference internal" href="#minimal">Minimal</a></li>
<li><a class="reference internal" href="#announce">Announce</a></li>
<li><a class="reference internal" href="#broadcast">Broadcast</a></li>
<li><a class="reference internal" href="#echo">Echo</a></li>
<li><a class="reference internal" href="#link">Link</a></li>
<li><a class="reference internal" href="#example-identify">Identification</a></li>
<li><a class="reference internal" href="#requests-responses">Requests &amp; Responses</a></li>
<li><a class="reference internal" href="#filetransfer">Filetransfer</a></li>
</ul>
</li>
</ul>
<h4>Previous topic</h4>
<p class="topless"><a href="reference.html"
title="previous chapter">API Reference</a></p>
<div role="note" aria-label="source link">
<h3>This Page</h3>
<ul class="this-page-menu">
<li><a href="_sources/examples.rst.txt"
rel="nofollow">Show Source</a></li>
</ul>
</div>
<div id="searchbox" style="display: none" role="search">
<h3 id="searchlabel">Quick search</h3>
<div class="searchformwrapper">
<form class="search" action="search.html" method="get">
<input type="text" name="q" aria-labelledby="searchlabel" />
<input type="submit" value="Go" />
</form>
</div>
</div>
<script>$('#searchbox').show(0);</script>
</div>
</div>
<div class="clearer"></div>
</div>
<div class="related" role="navigation" aria-label="related navigation">
<h3>Navigation</h3>
<ul>
<li class="right" style="margin-right: 10px">
<a href="genindex.html" title="General Index"
>index</a></li>
<li class="right" >
<a href="reference.html" title="API Reference"
>previous</a> |</li>
<li class="nav-item nav-item-0"><a href="index.html">Reticulum Network Stack 0.3.0 beta documentation</a> &#187;</li>
<li class="nav-item nav-item-this"><a href="">Code Examples</a></li>
</ul>
</div>
<div class="footer" role="contentinfo">
&#169; Copyright 2021, Mark Qvist.
Created using <a href="https://www.sphinx-doc.org/">Sphinx</a> 4.0.1.
</div>
</body>
</html>