node package manager

response-spy

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

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

Node module for intercepting HTTP responses sent in your apps.

Example

var http = require('http');
var intercept = require('response-spy');
 
http.createServer(function(req, res) {
  // 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');

How does it work?

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.

Use cases

  • generating cache
  • traffic analysis
  • etc

License MIT