Updating the prototype of ServerRequest in an express/node configuration

Question

Updating the prototype of ServerRequest in an express/node configuration

I'd like to augment the prototype of the request object in expressjs, but it isn't clear where this request is defined? I think it is http.ServerRequest, but I can't find that definition either.

What's the right way to do the following...

http.ServerRequest.prototype.redirect = function(path) { }

node.js
express

Answer 1

Look at Connect framework and his middleware libs. Every middleware extends request and response objects after their creation. Changing prototype of core objects not the best way because this can lead to unpredictable behavior in other modules.

Answer 2

Express itself adds it's utility methods to http.IncomingMessage.prototype, using this pattern in 2.*:

var http = require('http'),
    req = http.IncomingMessage.prototype;

req.foo = function(bar) {
  // Do cool stuff
};

And this pattern in 3.*:

var http = require('http');

var req = exports = module.exports = {
  __proto__: http.IncomingMessage.prototype
};

It's wise to be careful with monkey patching though, as Vadim Baryshev warns in his answer.