WebSocket Server

A simple nonblocking server dedicated to websockets.

• upgrades HTTP requests
• routes HTTP requests to simple websocket-controllers
• can filter HTTP requests
• passes Autobahn WebSocket Testsuite
• does NOT implement compression
• works well with apache >= 2.4
• installable via composer require timostamm/websocket-server
• minimal dependencies (react/socket, ratchet/rfc6455, guzzlehttp/psr7)
• graceful shutdown via signals (or manually)

Credits for the websocket protocol implementation go to ratchet/rfc6455.

Example

$loop = Factory::create(); // use a react event loop

// start server
$server = new WebsocketServer($loop, [
    'uri' => '127.0.0.1:23080'
]);

// add a controller 
$server->route([
    'match' => '/example/*',
    'controller' => new class() implements ControllerInterface
    {
        function onOpen(WebSocket $connection): void
        {
            print $connection . ' connected. Sending a "Hello".' . PHP_EOL;
            $connection->send('Hello');
        }

        function onMessage(WebSocket $from, string $payload, bool $binary): void
        {
            print $from . ' sent: ' . $payload . PHP_EOL;
        }

        function onClose(WebSocket $connection, ?Throwable $error): void
        {
            print $connection . ' disconnected.' . PHP_EOL;
        }

    }
]);

// This error handler will be called when an exception was thrown
// by a filter, a controller method or the underlying tcp server.
$server->on('error', function (Throwable $error) {
    print 'Server error: ' . $error->getMessage() . PHP_EOL;
});

$loop->run(); // the react event loop processes socket connections

Routing

This route will match paths starting with /example/.

$server->route([
    'match' => '/example/*',
    'controller' => $controller
]);

Placeholders are implemented using fnmatch().

This route will match any path:

$server->route([
    'controller' => $controller
]);

This route will deny the websocket handshake if the client did not specifiy one of the subprotocols:

$server->route([
    'protocols' => ['soap'],
    'controller' => $controller
]);

Request filters

This filter responds with a HTTP 403

$server->filter('example/403', function () {
    throw ResponseException::create(403);
});

This filter modifies the request

$server->filter('example/add-attribute', function (ServerRequestInterface $request) {
    return $request->withAttribute('X-filter', 'passed');
});

This filter allows only the specified origins

$server->filter('example/origin', new OriginFilter(['example.com']));

You can provide your or RequestMatcherInterface and RequestFilterInterface implementations. Filters can also be added via route():

$server->route([
    'match' => '/example/*', 
    'filter' => function(ServerRequestInterface $request){
        if ($request->getRequestTarget() === '/example/forbidden') {
            throw ResponseException::create(403);
        }
    }
    'controller' => ...
]);

Authentication

This library does not provide session integration, but provides support for bearer token authentication.

Extend AbstractTokenAuthenticator with your token verification code and return a user object. The user will be be available in the request attribute "user". If no token is present, the user attribute will be empty.

Use AuthorizationFilter to check whether a user is present. Supply a $checkUser function to check whether the user is authorized.

See examples/token-auth.php

Apache config

Add the following to a .htaccess file to proxy all requests with a Upgrade: websocket header to the websocket server.

<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteCond %{HTTP:Upgrade} =websocket [NC]
    RewriteRule ^(.*)$          ws://127.0.0.1:23080/$1 [P,L]
</IfModule>

Javascript

var ws = new WebSocket("ws://localhost:23080/hello/foo");
ws.onmessage = function (event) {
    console.log("message", event.data);
};

More controller features

You can implement one or more of the following interfaces to get access to the loop, clients connected to this controller, etc.

class MyCtrl implements ControllerInterface, LoopAwareInterface ConnectionListAwareInterface, OnShutDownInterface, OnLastCloseInterface, OnFirstOpenInterface
{

    function setLoop(\React\EventLoop\LoopInterface $loop, callable $exceptionHandler): void
    {
        print 'Got loop.' . PHP_EOL;
    }

    function setConnections(\SplObjectStorage $webSockets): void
    {
        print 'Got connection list.' . PHP_EOL;
    }
    
    function onShutDown(): PromiseInterface
    {
         // Will be called when the server is asked to shutdown.
         // Use this hook to finish important tasks, then resolve the promise.
    }

    function onLastClose(WebSocket $socket): void
    {
        print 'Last connection closed.' . PHP_EOL;
    }

    function onFirstOpen(WebSocket $socket): void
    {
        print 'First connection opened.' . PHP_EOL;
    }

    function onOpen(WebSocket $socket): void
    {
        print $socket . ' connected. Sending a "Hello".' . PHP_EOL;
        $socket->send('Hello');
    }

    function onMessage(WebSocket $from, string $payload, bool $binary): void
    {
        print $from . ' received: ' . $payload . PHP_EOL;
    }

    function onClose(WebSocket $socket): void
    {
        print $socket . ' disconnected.' . PHP_EOL;
    }

    function onError(WebSocket $socket, \Throwable $error): void
    {
        print $socket . ' error: ' . $error->getMessage() . PHP_EOL;
    }

}