1
 2/**
 3 * Module dependencies.
 4 */
 5
 6var Polling = require('./polling');
 7var qs = require('querystring');
 8var rDoubleSlashes = /\\\\n/g;
 9var rSlashes = /(\\)?\\n/g;
10var util = require('util');
11
12/**
13 * Module exports.
14 */
15
16module.exports = JSONP;
17
18/**
19 * JSON-P polling transport.
20 *
21 * @api public
22 */
23
24function JSONP (req) {
25  Polling.call(this, req);
26
27  this.head = '___eio[' + (req._query.j || '').replace(/[^0-9]/g, '') + '](';
28  this.foot = ');';
29}
30
31/**
32 * Inherits from Polling.
33 */
34
35util.inherits(JSONP, Polling);
36
37/**
38 * Handles incoming data.
39 * Due to a bug in \n handling by browsers, we expect a escaped string.
40 *
41 * @api private
42 */
43
44JSONP.prototype.onData = function (data) {
45  // we leverage the qs module so that we get built-in DoS protection
46  // and the fast alternative to decodeURIComponent
47  data = qs.parse(data).d;
48  if ('string' === typeof data) {
49    // client will send already escaped newlines as \\\\n and newlines as \\n
50    // \\n must be replaced with \n and \\\\n with \\n
51    data = data.replace(rSlashes, function (match, slashes) {
52      return slashes ? match : '\n';
53    });
54    Polling.prototype.onData.call(this, data.replace(rDoubleSlashes, '\\n'));
55  }
56};
57
58/**
59 * Performs the write.
60 *
61 * @api private
62 */
63
64JSONP.prototype.doWrite = function (data, options, callback) {
65  // we must output valid javascript, not valid json
66  // see: http://timelessrepo.com/json-isnt-a-javascript-subset
67  var js = JSON.stringify(data)
68    .replace(/\u2028/g, '\\u2028')
69    .replace(/\u2029/g, '\\u2029');
70
71  // prepare response
72  data = this.head + js + this.foot;
73
74  Polling.prototype.doWrite.call(this, data, options, callback);
75};