1
 2/*!
 3 * Connect - limit
 4 * Copyright(c) 2011 TJ Holowaychuk
 5 * MIT Licensed
 6 */
 7
 8/**
 9 * Module dependencies.
10 */
11
12var utils = require('../utils'),
13  brokenPause = utils.brokenPause;
14
15/**
16 * Limit:
17 *
18 *   Limit request bodies to the given size in `bytes`.
19 *
20 *   A string representation of the bytesize may also be passed,
21 *   for example "5mb", "200kb", "1gb", etc.
22 *
23 *     connect()
24 *       .use(connect.limit('5.5mb'))
25 *       .use(handleImageUpload)
26 *
27 * @param {Number|String} bytes
28 * @return {Function}
29 * @api public
30 */
31
32module.exports = function limit(bytes){
33  if ('string' == typeof bytes) bytes = utils.parseBytes(bytes);
34  if ('number' != typeof bytes) throw new Error('limit() bytes required');
35  return function limit(req, res, next){
36    var received = 0
37      , len = req.headers['content-length']
38        ? parseInt(req.headers['content-length'], 10)
39        : null;
40
41    // self-awareness
42    if (req._limit) return next();
43    req._limit = true;
44
45    // limit by content-length
46    if (len && len > bytes) return next(utils.error(413));
47
48    // limit
49    if (brokenPause) {
50      listen();
51    } else {
52      req.on('newListener', function handler(event) {
53        if (event !== 'data') return;
54
55        req.removeListener('newListener', handler);
56        // Start listening at the end of the current loop
57        // otherwise the request will be consumed too early.
58        // Sideaffect is `limit` will miss the first chunk,
59        // but that's not a big deal.
60        // Unfortunately, the tests don't have large enough
61        // request bodies to test this.
62        process.nextTick(listen);
63      });
64    };
65
66    next();
67
68    function listen() {
69      req.on('data', function(chunk) {
70        received += Buffer.isBuffer(chunk)
71          ? chunk.length :
72          Buffer.byteLength(chunk);
73
74        if (received > bytes) req.destroy();
75      });
76    };
77  };
78};