# PHP如何实现WebSocket ## 前言 WebSocket作为一种全双工通信协议，已经成为现代Web应用实时通信的核心技术。与传统的HTTP轮询相比，WebSocket能显著降低服务器负载并实现真正的实时数据传输。本文将深入探讨PHP实现WebSocket服务的完整方案，从协议原理到实战代码，帮助开发者构建高性能的实时应用。 ## 一、WebSocket协议基础 ### 1.1 WebSocket与HTTP的区别 | 特性 | WebSocket | HTTP | |---------------|-------------------------|----------------------| | 通信模式 | 全双工 | 半双工（请求-响应） | | 连接持久性 | 长期保持 | 短连接（默认） | | 头部开销 | 首次握手后极小 | 每次请求完整头部 | | 数据格式 | 二进制帧/文本帧 | 纯文本 | | 适用场景 | 实时应用（聊天、游戏等）| 传统网页请求 | ### 1.2 WebSocket握手过程 WebSocket连接通过HTTP升级头建立： 1. 客户端发送握手请求： ```http GET /chat HTTP/1.1 Host: example.com Upgrade: websocket Connection: Upgrade Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ== Sec-WebSocket-Version: 13 if (preg_match('/^websocket$/i', $_SERVER['HTTP_UPGRADE']) { $key = $_SERVER['HTTP_SEC_WEBSOCKET_KEY']; $accept = base64_encode(sha1($key . '258EAFA5-E914-47DA-95CA-C5AB0DC85B11', true)); header("HTTP/1.1 101 Switching Protocols"); header("Upgrade: websocket"); header("Connection: Upgrade"); header("Sec-WebSocket-Accept: $accept"); exit(); } $host = '0.0.0.0'; $port = 8080; $socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP); socket_set_option($socket, SOL_SOCKET, SO_REUSEADDR, 1); socket_bind($socket, $host, $port); socket_listen($socket); $clients = [$socket]; while (true) { $read = $clients; $write = $except = null; if (socket_select($read, $write, $except, 0) < 1) continue; // 处理新连接 if (in_array($socket, $read)) { $newClient = socket_accept($socket); $clients[] = $newClient; $key = array_search($socket, $read); unset($read[$key]); } // 处理消息 foreach ($read as $client) { $bytes = @socket_recv($client, $data, 2048, 0); if ($bytes === false || $bytes === 0) { // 断开处理 $key = array_search($client, $clients); unset($clients[$key]); socket_close($client); } else { // WebSocket帧解析（简化版） if (ord($data[0]) == 129) { $msg = unmask(substr($data, 6)); broadcast($msg, $client); } } } } function unmask($payload) { $length = ord($payload[1]) & 127; // 实际处理需要根据payload长度不同进行处理 return substr($payload, 4); } WebSocket帧结构：
0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-------+-+-------------+-------------------------------+ |F|R|R|R| opcode|M| Payload len | Extended payload length | |I|S|S|S| (4) |A| (7) | (16/64) | |N|V|V|V| |S| | (if payload len==126/127) | | |1|2|3| |K| | | +-+-+-+-+-------+-+-------------+ - - - - - - - - - - - - - - - + | Extended payload length continued, if payload len == 127 | + - - - - - - - - - - - - - - - +-------------------------------+ | |Masking-key, if MASK set to 1 | +-------------------------------+-------------------------------+ | Masking-key (continued) | Payload Data | +-------------------------------- - - - - - - - - - - - - - - - + : Payload Data continued ... : + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + | Payload Data continued ... | +---------------------------------------------------------------+ PHP解析实现：
function parseFrame($data) { $firstByte = ord($data[0]); $secondByte = ord($data[1]); $fin = ($firstByte & 0x80) >> 7; $opcode = $firstByte & 0x0F; $mask = ($secondByte & 0x80) >> 7; $payloadLength = $secondByte & 0x7F; $offset = 2; if ($payloadLength == 126) { $payloadLength = unpack('n', substr($data, $offset, 2))[1]; $offset += 2; } elseif ($payloadLength == 127) { $payloadLength = unpack('J', substr($data, $offset, 8))[1]; $offset += 8; } $masks = []; if ($mask) { $masks = array_map('ord', str_split(substr($data, $offset, 4))); $offset += 4; } $payload = substr($data, $offset); if ($mask) { $unmasked = ''; for ($i = 0; $i < strlen($payload); $i++) { $unmasked .= $payload[$i] ^ chr($masks[$i % 4]); } $payload = $unmasked; } return [ 'fin' => $fin, 'opcode' => $opcode, 'payload' => $payload ]; } 安装：
composer require cboden/ratchet 服务端实现：
use Ratchet\MessageComponentInterface; use Ratchet\ConnectionInterface; class Chat implements MessageComponentInterface { protected $clients; public function __construct() { $this->clients = new \SplObjectStorage; } public function onOpen(ConnectionInterface $conn) { $this->clients->attach($conn); echo "New connection: {$conn->resourceId}\n"; } public function onMessage(ConnectionInterface $from, $msg) { foreach ($this->clients as $client) { if ($client !== $from) { $client->send($msg); } } } public function onClose(ConnectionInterface $conn) { $this->clients->detach($conn); echo "Connection {$conn->resourceId} closed\n"; } public function onError(ConnectionInterface $conn, \Exception $e) { echo "Error: {$e->getMessage()}\n"; $conn->close(); } } $app = new Ratchet\App('localhost', 8080); $app->route('/chat', new Chat, ['*']); $app->run(); 安装：
pecl install swoole 服务端代码：
$server = new Swoole\WebSocket\Server("0.0.0.0", 9501); $server->on('Start', function($server) { echo "Server started at ws://0.0.0.0:9501\n"; }); $server->on('Open', function($server, $request) { echo "connection open: {$request->fd}\n"; }); $server->on('Message', function($server, $frame) { echo "received message: {$frame->data}\n"; foreach ($server->connections as $fd) { if ($fd !== $frame->fd) { $server->push($fd, $frame->data); } } }); $server->on('Close', function($server, $fd) { echo "connection close: {$fd}\n"; }); $server->start(); 性能对比测试（1000并发连接）：
| 方案 | 内存占用 | 吞吐量 (req/s) | CPU使用率 |
|---|---|---|---|
| 原生PHP | 120MB | 800 | 45% |
| Ratchet | 85MB | 3,200 | 30% |
| Swoole | 50MB | 12,500 | 15% |
map $http_upgrade $connection_upgrade { default upgrade; '' close; } server { listen 80; server_name ws.example.com; location / { proxy_pass http://127.0.0.1:8080; proxy_http_version 1.1; proxy_set_header Upgrade $http_upgrade; proxy_set_header Connection $connection_upgrade; proxy_set_header Host $host; # 重要超时设置 proxy_read_timeout 86400s; proxy_send_timeout 86400s; } } $context = new \React\Socket\SecureServer( new \React\Socket\SocketServer('0.0.0.0:8080'), new \React\EventLoop\Loop(), [ 'local_cert' => '/path/to/cert.pem', 'local_pk' => '/path/to/privkey.pem', 'allow_self_signed' => false, 'verify_peer' => true ] ); function filterMessage($msg) { // 防XSS $msg = htmlspecialchars($msg, ENT_QUOTES); // 敏感词过滤 $blacklist = ['badword1', 'badword2']; $msg = str_ireplace($blacklist, '***', $msg); // 长度限制 return mb_substr($msg, 0, 200); } class ChatRoom implements MessageComponentInterface { private $rooms = []; public function onMessage(ConnectionInterface $conn, $msg) { $data = json_decode($msg, true); switch ($data['type']) { case 'join': $this->rooms[$data['room']][$conn->resourceId] = $conn; break; case 'message': foreach ($this->rooms[$data['room']] as $client) { if ($client !== $conn) { $client->send(json_encode([ 'user' => $data['user'], 'text' => $data['text'] ])); } } break; } } } class StockTicker implements MessageComponentInterface { private $clients; private $timer; public function __construct() { $this->clients = new \SplObjectStorage; $this->setupDataFeed(); } private function setupDataFeed() { $loop = \React\EventLoop\Factory::create(); $this->timer = $loop->addPeriodicTimer(1, function() { $stocks = [ 'AAPL' => rand(145, 155), 'GOOG' => rand(2500, 2600) ]; foreach ($this->clients as $client) { $client->send(json_encode($stocks)); } }); $loop->run(); } } // 使用连接池管理 class ConnectionPool { private $pool; private $maxConnections; public function __construct($max) { $this->maxConnections = $max; $this->pool = new \SplQueue; } public function getConnection() { if (!$this->pool->isEmpty()) { return $this->pool->dequeue(); } if (count($this->pool) < $this->maxConnections) { return $this->createNewConnection(); } throw new \RuntimeException('Connection limit reached'); } private function createNewConnection() { // 创建新连接逻辑 } } function sendCompressed($conn, $data) { if (function_exists('gzencode') && strlen($data) > 1024) { $compressed = gzencode($data, 6); $conn->send(base64_encode($compressed), 'binary'); } else { $conn->send($data); } } PHP实现WebSocket服务虽然面临传统CGI模式的限制，但通过扩展库和正确的架构设计，完全可以构建高性能的实时应用。生产环境中建议：
随着PHP协程和异步IO的持续发展，PHP在实时通信领域的竞争力将不断增强。建议开发者持续关注Swoole等创新项目的发展动态。
Q：PHP-FPM模式下能使用WebSocket吗？ A：传统PHP-FPM模式不适合长连接服务，必须使用常驻内存的PHP CLI模式。
Q：如何检测连接断开？ A：需要通过心跳机制（ping/pong）定期检测，Swoole等库已内置支持。
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