networking

Compare original and translation side by side

🇺🇸

Original

English
🇨🇳

Translation

Chinese

Game Networking

游戏网络

Implement real-time multiplayer networking with WebSocket, UDP, and latency optimization.
实现基于WebSocket、UDP的实时多人游戏网络,并进行延迟优化。

WebSocket Game Server

WebSocket游戏服务器

javascript
const WebSocket = require('ws');

class GameServer {
  constructor(port = 8080) {
    this.wss = new WebSocket.Server({ port });
    this.players = new Map();
    this.setupHandlers();
  }

  setupHandlers() {
    this.wss.on('connection', (ws, req) => {
      const playerId = this.generateId();
      const player = { ws, state: {}, joinedAt: Date.now() };
      this.players.set(playerId, player);

      ws.on('message', (data) => this.handleMessage(playerId, data));
      ws.on('close', () => this.handleDisconnect(playerId));
      ws.on('error', (err) => this.handleError(playerId, err));

      this.sendToPlayer(playerId, { type: 'connected', playerId });
    });
  }

  handleMessage(playerId, data) {
    try {
      const msg = JSON.parse(data);
      // Validate message structure
      if (!msg.type) throw new Error('Missing message type');
      this.processGameMessage(playerId, msg);
    } catch (err) {
      console.error(`Invalid message from ${playerId}:`, err.message);
    }
  }

  broadcast(msg, exclude = null) {
    const data = JSON.stringify(msg);
    this.players.forEach((player, id) => {
      if (id !== exclude && player.ws.readyState === WebSocket.OPEN) {
        player.ws.send(data);
      }
    });
  }
}
javascript
const WebSocket = require('ws');

class GameServer {
  constructor(port = 8080) {
    this.wss = new WebSocket.Server({ port });
    this.players = new Map();
    this.setupHandlers();
  }

  setupHandlers() {
    this.wss.on('connection', (ws, req) => {
      const playerId = this.generateId();
      const player = { ws, state: {}, joinedAt: Date.now() };
      this.players.set(playerId, player);

      ws.on('message', (data) => this.handleMessage(playerId, data));
      ws.on('close', () => this.handleDisconnect(playerId));
      ws.on('error', (err) => this.handleError(playerId, err));

      this.sendToPlayer(playerId, { type: 'connected', playerId });
    });
  }

  handleMessage(playerId, data) {
    try {
      const msg = JSON.parse(data);
      // Validate message structure
      if (!msg.type) throw new Error('Missing message type');
      this.processGameMessage(playerId, msg);
    } catch (err) {
      console.error(`Invalid message from ${playerId}:`, err.message);
    }
  }

  broadcast(msg, exclude = null) {
    const data = JSON.stringify(msg);
    this.players.forEach((player, id) => {
      if (id !== exclude && player.ws.readyState === WebSocket.OPEN) {
        player.ws.send(data);
      }
    });
  }
}

UDP for Low Latency

低延迟UDP实现

javascript
const dgram = require('dgram');

class UDPGameServer {
  constructor(port = 7777) {
    this.socket = dgram.createSocket('udp4');
    this.clients = new Map(); // address:port -> client
    this.sequence = 0;

    this.socket.on('message', (msg, rinfo) => {
      const key = `${rinfo.address}:${rinfo.port}`;
      this.handlePacket(key, msg, rinfo);
    });

    this.socket.bind(port);
  }

  send(client, data, reliable = false) {
    const packet = this.createPacket(data, reliable);
    this.socket.send(packet, client.port, client.address);
  }

  createPacket(data, reliable) {
    const seq = this.sequence++;
    const header = Buffer.alloc(4);
    header.writeUInt16LE(seq, 0);
    header.writeUInt8(reliable ? 1 : 0, 2);
    return Buffer.concat([header, data]);
  }
}
javascript
const dgram = require('dgram');

class UDPGameServer {
  constructor(port = 7777) {
    this.socket = dgram.createSocket('udp4');
    this.clients = new Map(); // address:port -> client
    this.sequence = 0;

    this.socket.on('message', (msg, rinfo) => {
      const key = `${rinfo.address}:${rinfo.port}`;
      this.handlePacket(key, msg, rinfo);
    });

    this.socket.bind(port);
  }

  send(client, data, reliable = false) {
    const packet = this.createPacket(data, reliable);
    this.socket.send(packet, client.port, client.address);
  }

  createPacket(data, reliable) {
    const seq = this.sequence++;
    const header = Buffer.alloc(4);
    header.writeUInt16LE(seq, 0);
    header.writeUInt8(reliable ? 1 : 0, 2);
    return Buffer.concat([header, data]);
  }
}

Protocol Selection Guide

协议选择指南

ProtocolLatencyReliabilityUse Case
WebSocket20-50msHighWeb games, chat
UDP5-20msNoneFPS, racing
QUIC10-30msConfigurableModern hybrid
TCP30-100msHighTurn-based, MMO
协议延迟可靠性使用场景
WebSocket20-50ms网页游戏、聊天
UDP5-20msFPS游戏、竞速游戏
QUIC10-30ms可配置现代混合场景
TCP30-100ms回合制游戏、大型多人在线游戏(MMO)

Troubleshooting

故障排查

Common Failure Modes

常见故障模式

ErrorRoot CauseSolution
ECONNRESETClient disconnectGraceful handling
High latencyNetwork congestionEnable delta compression
Packet lossUDP unreliabilityAdd reliability layer
WebSocket timeoutIdle connectionImplement heartbeat
错误根本原因解决方案
ECONNRESET客户端断开连接优雅处理断开
高延迟网络拥堵启用增量压缩
丢包UDP不可靠特性添加可靠性层
WebSocket超时连接空闲实现心跳机制

Debug Checklist

调试检查清单

bash
undefined
bash
undefined

Check active connections

检查活跃连接数

netstat -an | grep :8080 | wc -l
netstat -an | grep :8080 | wc -l

Monitor bandwidth

监控带宽

iftop -i eth0 -f "port 8080"
iftop -i eth0 -f "port 8080"

Capture packets

捕获数据包

tcpdump -i eth0 port 8080 -w capture.pcap
undefined
tcpdump -i eth0 port 8080 -w capture.pcap
undefined

Unit Test Template

单元测试模板

javascript
describe('GameServer', () => {
  let server, client;

  beforeEach(() => {
    server = new GameServer(8081);
    client = new WebSocket('ws://localhost:8081');
  });

  afterEach(() => {
    client.close();
    server.close();
  });

  test('accepts connections', (done) => {
    client.on('open', () => {
      expect(server.players.size).toBe(1);
      done();
    });
  });

  test('broadcasts messages', (done) => {
    client.on('message', (data) => {
      const msg = JSON.parse(data);
      expect(msg.type).toBe('connected');
      done();
    });
  });
});
javascript
describe('GameServer', () => {
  let server, client;

  beforeEach(() => {
    server = new GameServer(8081);
    client = new WebSocket('ws://localhost:8081');
  });

  afterEach(() => {
    client.close();
    server.close();
  });

  test('accepts connections', (done) => {
    client.on('open', () => {
      expect(server.players.size).toBe(1);
      done();
    });
  });

  test('broadcasts messages', (done) => {
    client.on('message', (data) => {
      const msg = JSON.parse(data);
      expect(msg.type).toBe('connected');
      done();
    });
  });
});

Resources

资源

  • assets/
    - Server templates
  • scripts/
    - Network testing tools
  • references/
    - Protocol guides
  • assets/
    - 服务器模板
  • scripts/
    - 网络测试工具
  • references/
    - 协议指南