response-spy

Intercepts HTTP response headers && body (without any man-in-the-middle http proxy server)

 _ __ ___  ___ _ __   ___  _ __  ___  ___        ___ _ __  _   _ 
| '__/ _ \/ __| '_ \ / _ \| '_ \/ __|/ _ \      / __| '_ \| | | |
| | |  __/\__ \ |_) | (_) | | | \__ \  __/      \__ \ |_) | |_| |
|_|  \___||___/ .__/ \___/|_| |_|___/\___|      |___/ .__/ \__, |
              | |                                   | |     __/ |
              |_|                                   |_|    |___/ 

Node module for intercepting HTTP responses sent in your apps.

var http = require('http');
var intercept = require('response-spy');
 
http.createServer(function(reqres) {
  // returns a readable stream with the response output as the data 
  var stream = intercept(res);
 
  // You can also see the headers sent, uncomment below 
  /*
  stream.on('headers', function(headers, statusCode) {
    // headers === Array || null (implicit headers)
    console.log('url: %s, headers: ', req.url, headers);
  });
  */
 
  stream.pipe(process.stdout);
 
  if (req.url === '/') {
    res.setHeader('X-Powered-By', 'alessioalex');
    res.writeHead(200, { 'Content-Type': 'text/html', 'X-Pid': 1239 });
    res.end('Hello world\n');
  } else if (req.url === '/pipe') {
    require('fs').createReadStream(__filename).pipe(res);
  } else if (req.url === '/implicit-headers') {
    res.end('go\n');
  } else {
    res.writeHead(404, { 'Connection': 'closed', 'Content-Type': 'text/html' });
    res.end('Page Not Found\n');
  }
}).listen(5000);
console.log('Ok good, now visit http://localhost:5000/ && http://localhost:5000/pipe');
console.log('.. and then check your terminal');

It overrides the OutgoingMessage native functions (write, writeHead, end, setHeader, removeHeader), without affecting your apps (the original functions will be called with the same params, these are just thin wrappers). With response-spy you practically get a ReadableStream from your response object.

  • generating cache
  • traffic analysis
  • etc