node_modules/http-proxy/lib/http-proxy.js

var http      = require('http'),
    https     = require('https'),
    url       = require('url'),
    httpProxy = require('./http-proxy/');

/**
 * Export the proxy "Server" as the main export.
 */
module.exports = httpProxy.Server;

/**
 * Creates the proxy server.
 *
 * Examples:
 *
 *    httpProxy.createProxyServer({ .. }, 8000)
 *    // => '{ web: [Function], ws: [Function] ... }'
 *
 * @param {Object} Options Config object passed to the proxy
 *
 * @return {Object} Proxy Proxy object with handlers for `ws` and `web` requests
 *
 * @api public
 */

module.exports.createProxyServer =
  module.exports.createServer =
  module.exports.createProxy = function createProxyServer(options) {
  /*
   *  `options` is needed and it must have the following layout:
   *
   *  {
   *    target : <url string to be parsed with the url module>
   *    forward: <url string to be parsed with the url module>
   *    agent  : <object to be passed to http(s).request>
   *    ssl    : <object to be passed to https.createServer()>
   *    ws     : <true/false, if you want to proxy websockets>
   *    xfwd   : <true/false, adds x-forward headers>
   *    secure : <true/false, verify SSL certificate>
   *    toProxy: <true/false, explicitly specify if we are proxying to another proxy>
   *    prependPath: <true/false, Default: true - specify whether you want to prepend the target's path to the proxy path>
   *    ignorePath: <true/false, Default: false - specify whether you want to ignore the proxy path of the incoming request>
   *    localAddress : <Local interface string to bind for outgoing connections>
   *    changeOrigin: <true/false, Default: false - changes the origin of the host header to the target URL>
   *    auth   : Basic authentication i.e. 'user:password' to compute an Authorization header.  
   *    hostRewrite: rewrites the location hostname on (301/302/307/308) redirects, Default: null.
   *    autoRewrite: rewrites the location host/port on (301/302/307/308) redirects based on requested host/port. Default: false.
   *    protocolRewrite: rewrites the location protocol on (301/302/307/308) redirects to 'http' or 'https'. Default: null.
   *  }
   *
   *  NOTE: `options.ws` and `options.ssl` are optional.
   *    `options.target and `options.forward` cannot be
   *    both missing
   *  }
   */

  return new httpProxy.Server(options);
};