web/app/core/App.php

<?php

class App
{
    public array $config;
    public object $database;
    public object $session;

    public function __construct()
    {
        // Require configuration file
        $this->config = require __DIR__ . '/../config.php';

        // Connect to database 
        $this->database = new Database($this->config['database']);

        // Instantiate new session
        $this->session = new Session;
    }

    // Grab model
    public function model(string $model): object
    {
        // Require model file
        require __DIR__ . '/../model/' . $model . '.php';
        // Instantiate model
        return new $model();
    }

    // Render given view
    public function view(string $view, array $data = []): void
    {
        // Import variables into the current symbol table from an array
        extract($data);
        // Require view file
        require __DIR__ . '/../view/' . $view . '.php';
    }

    // Turn data array into JSON response
    public function api(array $data, int $status_code = 200): void
    {
        // Set headers
        http_response_code($status_code);
        header('Content-type: application/json');
        // Convert and respond with data
        echo json_encode($data);
    }
}