js获取头部信息

fetch('https://api.example.com/data')
  .then(response => {
    // 获取所有响应头部
    const headers = response.headers;
    // 获取单个响应头部
    const contentType = response.headers.get('Content-Type');
    console.log(headers);
    console.log(contentType);
  })
  .catch(error => console.error('Error:', error));

const xhr = new XMLHttpRequest();
xhr.open('GET', 'https://api.example.com/data', true);
xhr.onreadystatechange = function() {
  if (xhr.readyState === 4 && xhr.status === 200) {
    // 获取所有响应头部
    const headers = xhr.getAllResponseHeaders();
    // 获取单个响应头部
    const contentType = xhr.getResponseHeader('Content-Type');
    console.log(headers);
    console.log(contentType);
  }
};
xhr.send();

const http = require('http');

http.createServer((req, res) => {
  // 获取所有请求头部
  const headers = req.headers;
  // 获取单个请求头部
  const userAgent = req.headers['user-agent'];
  console.log(headers);
  console.log(userAgent);

  res.writeHead(200, { 'Content-Type': 'text/plain' });
  res.end('Hello World\n');
}).listen(3000);

const express = require('express');
const app = express();

app.get('/', (req, res) => {
  // 获取所有请求头部
  const headers = req.headers;
  // 获取单个请求头部
  const userAgent = req.headers['user-agent'];
  console.log(headers);
  console.log(userAgent);

  res.send('Hello World');
});

app.listen(3000, () => {
  console.log('Server is running on port 3000');
});