Node.js中http模块详解

Node.js 中 http 模块全部 API 详解

Node.js 的 http 模块提供了创建 HTTP 服务器和客户端的功能。以下是 http 模块的所有 API 详解：

1. 创建 HTTP 服务器

const http = require('http');// 1. 基本服务器
const server = http.createServer((req, res) => {res.writeHead(200, { 'Content-Type': 'text/plain' });res.end('Hello World\n');
});server.listen(3000, '127.0.0.1', () => {console.log('服务器运行在 http://127.0.0.1:3000/');
});// 2. 使用 Server 类
const server2 = new http.Server((req, res) => {res.writeHead(200, { 'Content-Type': 'text/plain' });res.end('Hello World\n');
});server2.listen(3001);// 3. 处理不同请求方法
const server3 = http.createServer((req, res) => {switch (req.method) {case 'GET':handleGet(req, res);break;case 'POST':handlePost(req, res);break;default:res.writeHead(405);res.end('Method Not Allowed');}
});function handleGet(req, res) {res.writeHead(200, { 'Content-Type': 'application/json' });res.end(JSON.stringify({ message: 'GET request handled' }));
}function handlePost(req, res) {let body = '';req.on('data', chunk => {body += chunk.toString();});req.on('end', () => {try {const data = JSON.parse(body);res.writeHead(200, { 'Content-Type': 'application/json' });res.end(JSON.stringify({ received: data }));} catch (e) {res.writeHead(400);res.end('Invalid JSON');}});
}

2. 服务器事件

// 1. 连接事件
server.on('connection', (socket) => {console.log('新连接建立');socket.on('data', (chunk) => {console.log('收到数据:', chunk.toString());});socket.on('end', () => {console.log('连接结束');});socket.on('error', (err) => {console.error('Socket 错误:', err);});
});// 2. 请求事件
server.on('request', (req, res) => {console.log('收到请求:', req.method, req.url);
});// 3. 错误事件
server.on('error', (err) => {console.error('服务器错误:', err);
});// 4. 关闭事件
server.on('close', () => {console.log('服务器关闭');
});// 5. 监听事件
server.on('listening', () => {console.log('服务器开始监听');
});

3. 服务器方法

// 1. 启动服务器
server.listen(3000, '127.0.0.1', () => {console.log('服务器运行在 http://127.0.0.1:3000/');
});// 2. 关闭服务器
server.close(() => {console.log('服务器已关闭');
});// 3. 获取服务器地址信息
const address = server.address();
console.log('服务器地址:', address);
// { address: '127.0.0.1', family: 'IPv4', port: 3000 }// 4. 设置超时
server.setTimeout(60000); // 60 秒
server.on('timeout', (socket) => {console.log('连接超时');
});// 5. 获取最大头信息大小
const maxHeaderSize = server.maxHeaderSize;
console.log('最大头信息大小:', maxHeaderSize);// 6. 设置最大头信息大小
server.maxHeaderSize = 16384; // 16KB

4. 请求对象 (http.IncomingMessage)

// 1. 请求属性
server.on('request', (req, res) => {console.log('请求方法:', req.method);console.log('请求 URL:', req.url);console.log('请求头:', req.headers);console.log('HTTP 版本:', req.httpVersion);console.log('HTTP 版本号:', req.httpVersionMajor, req.httpVersionMinor);console.log('原始 URL:', req.rawHeaders);console.log('原始尾随头信息:', req.rawTrailers);console.log('尾随头信息:', req.trailers);console.log('Socket:', req.socket);console.log('连接:', req.connection);
});// 2. 请求事件
server.on('request', (req, res) => {// 数据事件req.on('data', (chunk) => {console.log('收到数据块:', chunk);});// 结束事件req.on('end', () => {console.log('请求数据接收完成');});// 错误事件req.on('error', (err) => {console.error('请求错误:', err);});// 关闭事件req.on('close', () => {console.log('请求关闭');});// 中止事件req.on('aborted', () => {console.log('请求中止');});
});// 3. 请求方法
server.on('request', (req, res) => {// 销毁请求req.destroy();// 暂停请求req.pause();// 恢复请求req.resume();
});

5. 响应对象 (http.ServerResponse)

// 1. 响应属性
server.on('request', (req, res) => {console.log('响应头已发送:', res.headersSent);console.log('响应完成:', res.finished);console.log('响应发送中:', res.sending);console.log('响应状态码:', res.statusCode);console.log('响应状态消息:', res.statusMessage);console.log('Socket:', res.socket);
});// 2. 响应方法
server.on('request', (req, res) => {// 设置响应头res.setHeader('Content-Type', 'text/plain');res.setHeader('X-Custom-Header', 'value');// 获取响应头const contentType = res.getHeader('Content-Type');console.log('Content-Type:', contentType);// 移除响应头res.removeHeader('X-Custom-Header');// 写入响应头res.writeHead(200, { 'Content-Type': 'text/plain' });// 写入响应体res.write('Hello ');res.write('World\n');// 结束响应res.end();// 刷新响应头res.flushHeaders();
});// 3. 响应事件
server.on('request', (req, res) => {// 完成事件res.on('finish', () => {console.log('响应完成');});// 关闭事件res.on('close', () => {console.log('响应关闭');});
});

6. HTTP 客户端

// 1. 发送 GET 请求
const getReq = http.get('http://example.com', (res) => {console.log('状态码:', res.statusCode);console.log('头信息:', res.headers);let data = '';res.on('data', chunk => {data += chunk;});res.on('end', () => {console.log('响应数据:', data);});
});getReq.on('error', (err) => {console.error('请求错误:', err);
});// 2. 发送 POST 请求
const postData = JSON.stringify({ key: 'value' });const options = {hostname: 'example.com',path: '/api/data',method: 'POST',headers: {'Content-Type': 'application/json','Content-Length': Buffer.byteLength(postData)}
};const postReq = http.request(options, (res) => {console.log('状态码:', res.statusCode);let data = '';res.on('data', chunk => {data += chunk;});res.on('end', () => {console.log('响应数据:', data);});
});postReq.on('error', (err) => {console.error('请求错误:', err);
});postReq.write(postData);
postReq.end();// 3. 使用 Agent
const agent = new http.Agent({keepAlive: true,keepAliveMsecs: 1000,maxSockets: 10
});const reqWithAgent = http.request({hostname: 'example.com',path: '/',agent: agent
}, (res) => {// 处理响应
});// 4. 取消请求
const req = http.request(options, (res) => {// 处理响应
});req.abort(); // 取消请求

7. HTTP 代理

// 1. 创建代理服务器
const proxyServer = http.createServer((req, res) => {const options = {hostname: 'target-server.com',path: req.url,method: req.method,headers: req.headers};const proxyReq = http.request(options, (proxyRes) => {res.writeHead(proxyRes.statusCode, proxyRes.headers);proxyRes.pipe(res);});proxyReq.on('error', (err) => {console.error('代理请求错误:', err);res.writeHead(500);res.end('Proxy Error');});req.pipe(proxyReq);
});proxyServer.listen(8080);// 2. 使用 http-proxy-middleware
const express = require('express');
const { createProxyMiddleware } = require('http-proxy-middleware');const app = express();app.use('/api', createProxyMiddleware({target: 'http://target-server.com',changeOrigin: true,pathRewrite: {'^/api': ''},onProxyRes: (proxyRes, req, res) => {proxyRes.headers['Access-Control-Allow-Origin'] = '*';}
}));app.listen(3000);

8. HTTPS 服务器

const https = require('https');
const fs = require('fs');// 1. 创建 HTTPS 服务器
const options = {key: fs.readFileSync('private.key'),cert: fs.readFileSync('certificate.crt')
};const httpsServer = https.createServer(options, (req, res) => {res.writeHead(200);res.end('Secure connection');
});httpsServer.listen(443);// 2. HTTPS 客户端
const httpsReq = https.get('https://example.com', (res) => {console.log('状态码:', res.statusCode);let data = '';res.on('data', chunk => {data += chunk;});res.on('end', () => {console.log('响应数据:', data);});
});httpsReq.on('error', (err) => {console.error('请求错误:', err);
});

9. 中间件模式

// 1. 基本中间件
function middleware(req, res, next) {console.log('请求:', req.method, req.url);next();
}// 2. 错误处理中间件
function errorHandler(err, req, res, next) {console.error('错误:', err);res.writeHead(500);res.end('Internal Server Error');
}// 3. 中间件链
const middlewares = [middleware,(req, res, next) => {req.timestamp = Date.now();next();},(req, res, next) => {console.log('请求时间:', req.timestamp);next();}
];// 4. 应用中间件
function applyMiddlewares(req, res, middlewares) {let index = 0;function next() {if (index < middlewares.length) {const middleware = middlewares[index++];middleware(req, res, next);} else {// 所有中间件处理完毕，发送响应res.writeHead(200, { 'Content-Type': 'text/plain' });res.end('Hello World\n');}}next();
}// 5. 使用中间件
const server = http.createServer((req, res) => {applyMiddlewares(req, res, middlewares);
});

10. 实际应用示例

// 1. 文件服务器
const fileServer = http.createServer((req, res) => {const filePath = path.join(__dirname, req.url);fs.stat(filePath, (err, stats) => {if (err) {res.writeHead(404);res.end('File Not Found');return;}if (stats.isFile()) {const stream = fs.createReadStream(filePath);res.writeHead(200, { 'Content-Type': getContentType(filePath) });stream.pipe(res);} else {res.writeHead(403);res.end('Forbidden');}});
});function getContentType(filePath) {const ext = path.extname(filePath);const contentTypes = {'.html': 'text/html','.js': 'text/javascript','.css': 'text/css','.json': 'application/json','.png': 'image/png','.jpg': 'image/jpeg','.gif': 'image/gif'};return contentTypes[ext] || 'application/octet-stream';
}// 2. API 服务器
const apiServer = http.createServer((req, res) => {const url = new URL(req.url, `http://${req.headers.host}`);if (url.pathname === '/api/users') {if (req.method === 'GET') {res.writeHead(200, { 'Content-Type': 'application/json' });res.end(JSON.stringify([{ id: 1, name: 'User 1' },{ id: 2, name: 'User 2' }]));} else if (req.method === 'POST') {let body = '';req.on('data', chunk => {body += chunk.toString();});req.on('end', () => {try {const user = JSON.parse(body);res.writeHead(201, { 'Content-Type': 'application/json' });res.end(JSON.stringify({ id: 3, ...user }));} catch (e) {res.writeHead(400);res.end('Invalid JSON');}});} else {res.writeHead(405);res.end('Method Not Allowed');}} else {res.writeHead(404);res.end('Not Found');}
});// 3. 负载均衡器
const servers = [{ host: 'server1.example.com', port: 3001 },{ host: 'server2.example.com', port: 3002 },{ host: 'server3.example.com', port: 3003 }
];let currentServer = 0;const loadBalancer = http.createServer((req, res) => {const server = servers[currentServer];currentServer = (currentServer + 1) % servers.length;const options = {hostname: server.host,port: server.port,path: req.url,method: req.method,headers: req.headers};const proxyReq = http.request(options, (proxyRes) => {res.writeHead(proxyRes.statusCode, proxyRes.headers);proxyRes.pipe(res);});proxyReq.on('error', (err) => {console.error('代理请求错误:', err);res.writeHead(502);res.end('Bad Gateway');});req.pipe(proxyReq);
});

http 模块的主要特点：

1. 提供 HTTP 服务器和客户端功能
2. 支持请求和响应处理
3. 支持 HTTPS
4. 提供事件驱动 API
5. 支持流式处理

使用建议：

1. 使用事件处理请求和响应
2. 正确处理错误情况
3. 使用流式处理大文件
4. 设置适当的超时
5. 考虑使用更高级的框架（如 Express）简化开发