Add the ability to limit the maximum concurrent connections per appli… (#143)

* Add the ability to limit the maximum concurrent connections per application

Co-Authored-By: AlShahawi <alshahawi@outlook.com>

config/websockets.php

@@ -8,6 +8,9 @@ return [
      * This package comes with multi tenancy out of the box. Here you can
      * configure the different apps that can use the webSockets server.
      *
+     * Optionally you specify capacity so you can limit the maximum
+     * concurrent connections for a specific app.
+     *
      * Optionally you can disable client events so clients cannot send
      * messages to each other via the webSockets.
      */
@@ -17,6 +20,7 @@ return [
             'name' => env('APP_NAME'),
             'key' => env('PUSHER_APP_KEY'),
             'secret' => env('PUSHER_APP_SECRET'),
+            'capacity' => null,
             'enable_client_messages' => false,
             'enable_statistics' => true,
         ],

src/Apps/App.php

@@ -21,6 +21,9 @@ class App
     /** @var string|null */
     public $host;
 
+    /** @var int|null */
+    public $capacity = null;
+
     /** @var bool */
     public $clientMessagesEnabled = false;
 
@@ -80,6 +83,13 @@ class App
         return $this;
     }
 
+    public function setCapacity(?int $capacity)
+    {
+        $this->capacity = $capacity;
+
+        return $this;
+    }
+
     public function enableStatistics(bool $enabled = true)
     {
         $this->statisticsEnabled = $enabled;

src/Apps/ConfigAppProvider.php

@@ -73,7 +73,8 @@ class ConfigAppProvider implements AppProvider
 
         $app
             ->enableClientMessages($appAttributes['enable_client_messages'])
-            ->enableStatistics($appAttributes['enable_statistics']);
+            ->enableStatistics($appAttributes['enable_statistics'])
+            ->setCapacity($appAttributes['capacity'] ?? null);
 
         return $app;
     }

src/WebSockets/Exceptions/ConnectionsOverCapacity.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace BeyondCode\LaravelWebSockets\WebSockets\Exceptions;
+
+class ConnectionsOverCapacity extends WebSocketException
+{
+    public function __construct()
+    {
+        $this->message = 'Over capacity';
+
+        // @See https://pusher.com/docs/pusher_protocol#error-codes
+        // Indicates an error resulting in the connection
+        // being closed by Pusher, and that the client may reconnect after 1s or more.
+        $this->code = 4100;
+    }
+}

src/WebSockets/WebSocketHandler.php

@@ -14,6 +14,7 @@ use BeyondCode\LaravelWebSockets\WebSockets\Channels\ChannelManager;
 use BeyondCode\LaravelWebSockets\WebSockets\Exceptions\UnknownAppKey;
 use BeyondCode\LaravelWebSockets\WebSockets\Exceptions\WebSocketException;
 use BeyondCode\LaravelWebSockets\WebSockets\Messages\PusherMessageFactory;
+use BeyondCode\LaravelWebSockets\WebSockets\Exceptions\ConnectionsOverCapacity;
 
 class WebSocketHandler implements MessageComponentInterface
 {
@@ -29,6 +30,7 @@ class WebSocketHandler implements MessageComponentInterface
     {
         $this
             ->verifyAppKey($connection)
+            ->limitConcurrentConnections($connection)
             ->generateSocketId($connection)
             ->establishConnection($connection);
     }
@@ -73,6 +75,18 @@ class WebSocketHandler implements MessageComponentInterface
         return $this;
     }
 
+    protected function limitConcurrentConnections(ConnectionInterface $connection)
+    {
+        if (! is_null($capacity = $connection->app->capacity)) {
+            $connectionsCount = $this->channelManager->getConnectionCount($connection->app->id);
+            if ($connectionsCount >= $capacity) {
+                throw new ConnectionsOverCapacity();
+            }
+        }
+
+        return $this;
+    }
+
     protected function generateSocketId(ConnectionInterface $connection)
     {
         $socketId = sprintf('%d.%d', random_int(1, 1000000000), random_int(1, 1000000000));

tests/ConnectionTest.php

@@ -5,6 +5,7 @@ namespace BeyondCode\LaravelWebSockets\Tests;
 use BeyondCode\LaravelWebSockets\Apps\App;
 use BeyondCode\LaravelWebSockets\Tests\Mocks\Message;
 use BeyondCode\LaravelWebSockets\WebSockets\Exceptions\UnknownAppKey;
+use BeyondCode\LaravelWebSockets\WebSockets\Exceptions\ConnectionsOverCapacity;
 
 class ConnectionTest extends TestCase
 {
@@ -26,6 +27,17 @@ class ConnectionTest extends TestCase
         $connection->assertSentEvent('pusher:connection_established');
     }
 
+    /** @test */
+    public function app_can_not_exceed_maximum_capacity()
+    {
+        $this->app['config']->set('websockets.apps.0.capacity', 2);
+
+        $this->getConnectedWebSocketConnection(['test-channel']);
+        $this->getConnectedWebSocketConnection(['test-channel']);
+        $this->expectException(ConnectionsOverCapacity::class);
+        $this->getConnectedWebSocketConnection(['test-channel']);
+    }
+
     /** @test */
     public function successful_connections_have_the_app_attached()
     {

tests/TestCase.php

@@ -49,6 +49,7 @@ abstract class TestCase extends \Orchestra\Testbench\TestCase
                 'id' => 1234,
                 'key' => 'TestKey',
                 'secret' => 'TestSecret',
+                'capacity' => null,
                 'enable_client_messages' => false,
                 'enable_statistics' => true,
             ],