WebSockets

Also Known As

TL;DR

Explanation

WebSockets upgrade an HTTP connection to a persistent bidirectional channel — either side can push messages any time with minimal framing overhead. Ideal for: live dashboards, chat, collaborative editing, real-time game state, and push notifications. Traditional PHP (synchronous, request-per-process) is poorly suited to maintaining thousands of long-lived connections. Use a dedicated WebSocket server: Ratchet (PHP/ReactPHP), Swoole, or RoadRunner for PHP-native solutions. A common practical pattern: a lightweight Node.js or Go WebSocket server handles connections and publishes events via Redis Pub/Sub, while PHP handles business logic through standard HTTP endpoints.

Common Misconception

Why It Matters

Common Mistakes

• Not authenticating the WebSocket upgrade request — anyone can connect without credentials.
• Storing WebSocket connection state in memory on one server — horizontal scaling requires a shared state layer (Redis pub/sub).
• Not handling connection drops and reconnection logic on the client — connections drop; clients must reconnect.
• Broadcasting large payloads to all connections — use targeted pub/sub, not broadcast to all.

Code Examples

// WebSocket server with no authentication:
$server->on('open', function(Connection $conn): void {
    // No auth check — any client can connect and receive all messages
    $this->clients->attach($conn);
});
// Should verify a token in the upgrade request headers or first message

// PHP WebSocket server with Ratchet
use Ratchet\MessageComponentInterface;
use Ratchet\ConnectionInterface;

class ChatServer implements MessageComponentInterface {
    private \SplObjectStorage \$clients;
    public function __construct() { \$this->clients = new \SplObjectStorage(); }

    public function onOpen(ConnectionInterface \$conn): void {
        \$this->clients->attach(\$conn);
    }
    public function onMessage(ConnectionInterface \$from, \$msg): void {
        foreach (\$this->clients as \$client) {
            if (\$client !== \$from) \$client->send(\$msg); // broadcast
        }
    }
    public function onClose(ConnectionInterface \$conn): void {
        \$this->clients->detach(\$conn);
    }
    public function onError(ConnectionInterface \$conn, \Exception \$e): void {
        \$conn->close();
    }
}

// Start server: php bin/chat-server.php
// Client JS: const ws = new WebSocket('ws://yourapp.com:8080');

References

• ↗ https://developer.mozilla.org/en-US/docs/Web/API/WebSockets_API
• ↗ http://socketo.me/

Tags

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