Commit

app/lib/App/SSE/Sender.php

@@ -0,0 +1,35 @@
+<?php
+
+namespace App\SSE;
+
+/**
+ * Small class to abstract Server-Sent Events (SSE)
+ * 
+ * https://developer.mozilla.org/en-US/docs/Web/API/Server-sent_events/Using_server-sent_events
+ */
+class Sender 
+{
+    public function __construct()
+    {
+        header("Cache-Control: no-store");
+        header("Content-Type: text/event-stream");
+
+        // as session data is locked to prevent concurrent writes we
+        // make it read only to prevent the server from locking up
+        session_write_close();
+    }
+
+    public function send($data, $event = NULL): void
+    {
+        if ($event)
+        {
+            echo "event: $event\n";
+        }
+        echo "data: " . json_encode($data) ."";
+        echo "\n\n";
+
+        // send data to stream
+        ob_end_flush();
+        flush();
+    }
+}

app/view/pages/race/live-results.php

@@ -1,30 +1,10 @@
 <h1>Live resultater</h1>
 <p id="response">Venter på data...</p>
-<script type="text/javascript" src="http://code.jquery.com/jquery.min.js"></script>
+
 <script>
-function getContent(timestamp)
-{
-    var queryString = {'timestamp' : timestamp};
+var source = new EventSource('stream.php');
 
-    $.ajax(
-        {
-            type: 'GET',
-            url: 'long-polling.php',
-            data: queryString,
-            success: function(data){
-                // put result data into "obj"
-                var obj = jQuery.parseJSON(data);
-                // put the data_from_file into #response
-                $('#response').html(obj.data);
-                // call the function again, this time with the timestamp we just got from server.php
-                getContent(obj.timestamp);
-            }
-        }
-    );
-}
-
-// initialize jQuery
-$(function() {
-    getContent();
-});
+source.addEventListener('message', function(e) {
+  console.log(e.data);
+}, false);
 </script>

public/race/long-polling.php

@@ -1,38 +0,0 @@
-<?php $app = require '../../app/inc.php';
-
-use App\Timetable\TimeMapper;
-
-$timeMapper = new TimeMapper($app->database->conn);
-
-/**
- * Long polling
- */
-session_write_close();
-ignore_user_abort(false);
-set_time_limit(30);
-
-// if ajax request has send a timestamp, then $last_ajax_call = timestamp, else $last_ajax_call = null
-$last_ajax_call = isset($_GET['timestamp']) ? (int)$_GET['timestamp'] : NULL;
-
-// main loop
-while(TRUE)
-{
-    $time = $timeMapper->getLatest();
-
-    if ($time)
-    {
-        $last_change_in_timetable = $time->date->getTimestamp();
-
-        if ($time && $last_ajax_call == NULL || $last_change_in_timetable > $last_ajax_call)
-        {
-            exit(json_encode(["data" => json_encode($timeMapper->getAll()), "timestamp" => $last_change_in_timetable]));
-        }
-    }
-
-    // PHP caches file data, like requesting the size of a file, by default. clearstatcache() clears that cache
-    clearstatcache();
-    // wait for 1 sec (not very sexy as this blocks the PHP/Apache process, but that's how it goes)
-    sleep(1);
-    continue;
-}
-

public/race/stream.php

@@ -0,0 +1,30 @@
+<?php $app = require '../../app/inc.php';
+
+use App\Timetable\TimeMapper;
+use App\SSE\Sender;
+
+$timeMapper = new TimeMapper($app->database->conn);
+
+/**
+ * Server-Sent Events (SSE)
+ */
+
+$sse = new Sender();
+
+$last_change_in_timetable;
+while (!connection_aborted())
+{
+    $time = $timeMapper->getLatest();
+
+    if ($time)
+    {
+        $last_change_in_timetable = $time->date->getTimestamp();
+
+        if ($last_time == NULL || $last_change_in_timetable > $last_ajax_call)
+        {
+            $sse->send($timeMapper->getAll());
+        }
+    }
+
+    sleep(1);
+}