说说怎样利用 Node.js 代理解决跨域问题

//代理
const http = require('http');
const request = require('request');

const hostIp = '127.0.0.1';
const apiPort = 8070;
const imgPort = 8071;

//创建 API 代理服务
const apiServer = http.createServer((req, res) => {
  console.log('[apiServer]req.url='+req.url);
  const url = 'http://news-at.zhihu.com/story' + req.url;
  console.log('[apiServer]url='+url);
  const options = {
    url: url
  };

  function callback(error, response, body) {
    if (!error && response.statusCode === 200) {
      //编码类型
      res.setHeader('Content-Type', 'text/plain;charset=UTF-8');
      //允许跨域
      res.setHeader('Access-Control-Allow-Origin', '*');
      //返回代理内容
      res.end(body);
    }
  }

  request.get(options, callback);
});

//监听 API 端口
apiServer.listen(apiPort, hostIp, () => {
  console.log('代理接口，运行于 http://' + hostIp + ':' + apiPort + '/');
});

//创建图片代理服务
const imgServer = http.createServer((req, res) => {
  const url = 'http://pic2.zhimg.com/' +req.url.split('/img/')[1];
  console.log('[imgServer]url=' + url);
  const options = {
    url: url,
    encoding: null
  };

  function callback(error, response, body) {
    if (!error && response.statusCode === 200) {
      const contentType = response.headers['content-type'];
      res.setHeader('Content-Type', contentType);
      res.setHeader('Access-Control-Allow-Origin', '*');
      res.end(body);
    }
  }

  request.get(options, callback);


});

//监听图片端口
imgServer.listen(imgPort, hostIp, () => {
  console.log('代理图片，运行于 http://' + hostIp + ':' + imgPort + '/')
});