node.js bind() hack

bind_hack.js

/*
 * Author: Daniel Tralamazza <tralamazza@gmail.com>
 *
 * Patch Socket for a before connect event.
 * Important! You must require this module before anything else.
 *
 * Usage:
 *
 * var patch = require('./bind_hack');
 * var bind_f = process.binding('net').bind;
 * patch(function(socket, remote_port) {
 *   console.log('Socket.fd=' + socket.fd + ', remote port=' + remote_port);
 *   bind_f(socket.fd, 11111, '127.0.0.2'); // put some random port
 * });
 */

var timers = require('timers');

var last_port = null;
var o_active = timers.active;

var net = require('net');
var o_connect = net.Socket.prototype.connect;
net.Socket.prototype.connect = function() {
  last_port = Number(arguments[0]);
  o_connect.apply(this, arguments);
};

module.exports = function(callback) {
  timers.active = function(obj) {
    if (arguments.callee.caller.name == 'doConnect')
      callback(obj, last_port);
    o_active(obj);
  };
};