前端 WebSocket 实时通信实战指南

React 集成示例

import React, { useEffect, useCallback, useRef, useState } from 'react';

function WebSocketComponent() {
  const [messages, setMessages] = useState([]);
  const [input, setInput] = useState('');
  const wsClientRef = useRef(null);

  useEffect(() => {
    wsClientRef.current = new WebSocketClient('ws://localhost:8080');
    wsClientRef.current.connect();
    wsClientRef.current.on('chat', (payload) => {
      setMessages(prev => [...prev, payload]);
    });
    return () => {
      if (wsClientRef.current) wsClientRef.current.disconnect();
    };
  }, []);

  const handleSend = useCallback(() => {
    if (input.trim() && wsClientRef.current) {
      wsClientRef.current.send({ type: 'chat', payload: { message: input, user: 'Current User' } });
      setInput('');
    }
  }, [input]);

  return (
    <div>
      <div className="messages">
        {messages.map((message, index) => (
          <div key={index} className="message">
            <strong>{message.user}:</strong> {message.message}
          </div>
        ))}
      </div>
      <div className="input-area">
        <input 
          type="text" 
          value={input} 
          onChange={(e) => setInput(e.target.value)} 
          onKeyPress={(e) => e.key === 'Enter' && handleSend()} 
        />
        <button onClick={handleSend}>Send</button>
      </div>
    </div>
  );
}
export default WebSocketComponent;

进阶特性

认证与重试

class AuthWebSocketClient extends WebSocketClient {
  constructor(url, token) {
    super(url);
    this.token = token;
  }
  connect() {
    this.socket = new WebSocket(`${this.url}?token=${this.token}`);
    // 复用父类逻辑
  }
}

class RetryWebSocketClient extends WebSocketClient {
  constructor(url, options = {}) {
    super(url);
    this.maxReconnectAttempts = options.maxReconnectAttempts || 10;
    this.reconnectDelay = options.reconnectDelay || 1000;
    this.exponentialBackoff = options.exponentialBackoff || true;
  }
  reconnect() {
    if (this.reconnectAttempts < this.maxReconnectAttempts) {
      this.reconnectAttempts++;
      const delay = this.exponentialBackoff ? this.reconnectDelay * Math.pow(2, this.reconnectAttempts - 1) : this.reconnectDelay;
      setTimeout(() => this.connect(), delay);
    }
  }
}

消息队列

class QueueWebSocketClient extends WebSocketClient {
  constructor(url) {
    super(url);
    this.messageQueue = [];
  }
  connect() {
    super.connect();
    this.socket.onopen = () => {
      this.flushQueue();
    };
  }
  send(data) {
    if (this.connected) {
      this.socket.send(JSON.stringify(data));
    } else {
      this.messageQueue.push(data);
    }
  }
  flushQueue() {
    if (this.connected && this.messageQueue.length > 0) {
      this.messageQueue.forEach(message => this.socket.send(JSON.stringify(message)));
      this.messageQueue = [];
    }
  }
}

服务端与架构

Node.js 服务端

const WebSocket = require('ws');
const server = new WebSocket.Server({ port: 8080 });
const clients = new Set();

server.on('connection', (socket) => {
  console.log('Client connected');
  clients.add(socket);
  socket.send(JSON.stringify({ type: 'system', payload: 'Welcome!' }));

  socket.on('message', (message) => {
    try {
      const parsedMessage = JSON.parse(message);
      if (parsedMessage.type === 'heartbeat') {
        socket.send(JSON.stringify({ type: 'heartbeat' }));
        return;
      }
      clients.forEach(client => {
        if (client.readyState === WebSocket.OPEN) {
          client.send(JSON.stringify(parsedMessage));
        }
      });
    } catch (error) {
      console.error('Parse error:', error);
    }
  });

  socket.on('close', () => {
    clients.delete(socket);
  });
});

管理器模式

class WebSocketManager {
  static instance = null;
  constructor() {
    this.clients = {};
  }
  static getInstance() {
    if (!WebSocketManager.instance) {
      WebSocketManager.instance = new WebSocketManager();
    }
    return WebSocketManager.instance;
  }
  createClient(name, url, options = {}) {
    const client = new QueueWebSocketClient(url, options);
    this.clients[name] = client;
    client.connect();
    return client;
  }
  removeClient(name) {
    if (this.clients[name]) {
      this.clients[name].disconnect();
      delete this.clients[name];
    }
  }
  disconnectAll() {
    Object.values(this.clients).forEach(client => client.disconnect());
    this.clients = {};
  }
}

总结建议

WebSocket 是实时通信的重要方案，但需根据实际需求选择。过度使用可能导致复杂度增加或服务器负载过高。对于非实时场景，轮询可能更简单可靠。核心目标是实现稳定可靠的通信，而非炫技。