title: How to query a request at Nodejs Proxy Server?
body: <p>I have a Nodejs Proxy server like this: </p>
  
  <pre><code>`var http = require('http'),
  httpProxy = require('http-proxy');
  
  var proxy = httpProxy.createProxyServer({});
  
  proxy.on('proxyReq', function(proxyReq, req, res, options) {
    proxyReq.setHeader('X-Special-Proxy-Header', 'foobar');
  });
  
  var server = http.createServer(function(req, res) {
      console.log(req.body);
    proxy.web(req, res, {
      target: 'http://localhost:3000'
    });
   });
  
  console.log("listening on port 9000")
  server.listen(9000);`
  </code></pre>
  
  <p>What i want is get the req.body at the proxy server when i post a request to the Origin server, go through the proxy server. 
  I used "console.log(req.body);" at both proxy server and the origin server. I get the body object {"id": "user003"} at origin server, but undefined at the proxy server.
  So how can i get the req.body at proxy server?</p>