1/**
  2 * Module dependencies.
  3 */
  4
  5var pathRegexp = require('path-to-regexp');
  6var debug = require('debug')('express:router:layer');
  7
  8/**
  9 * Module variables.
 10 */
 11
 12var hasOwnProperty = Object.prototype.hasOwnProperty;
 13
 14/**
 15 * Expose `Layer`.
 16 */
 17
 18module.exports = Layer;
 19
 20function Layer(path, options, fn) {
 21  if (!(this instanceof Layer)) {
 22    return new Layer(path, options, fn);
 23  }
 24
 25  debug('new %s', path);
 26  options = options || {};
 27
 28  this.handle = fn;
 29  this.name = fn.name || '<anonymous>';
 30  this.params = undefined;
 31  this.path = undefined;
 32  this.regexp = pathRegexp(path, this.keys = [], options);
 33
 34  if (path === '/' && options.end === false) {
 35    this.regexp.fast_slash = true;
 36  }
 37}
 38
 39/**
 40 * Handle the error for the layer.
 41 *
 42 * @param {Error} error
 43 * @param {Request} req
 44 * @param {Response} res
 45 * @param {function} next
 46 * @api private
 47 */
 48
 49Layer.prototype.handle_error = function handle_error(error, req, res, next) {
 50  var fn = this.handle;
 51
 52  if (fn.length !== 4) {
 53    // not a standard error handler
 54    return next(error);
 55  }
 56
 57  try {
 58    fn(error, req, res, next);
 59  } catch (err) {
 60    next(err);
 61  }
 62};
 63
 64/**
 65 * Handle the request for the layer.
 66 *
 67 * @param {Request} req
 68 * @param {Response} res
 69 * @param {function} next
 70 * @api private
 71 */
 72
 73Layer.prototype.handle_request = function handle(req, res, next) {
 74  var fn = this.handle;
 75
 76  if (fn.length > 3) {
 77    // not a standard request handler
 78    return next();
 79  }
 80
 81  try {
 82    fn(req, res, next);
 83  } catch (err) {
 84    next(err);
 85  }
 86};
 87
 88/**
 89 * Check if this route matches `path`, if so
 90 * populate `.params`.
 91 *
 92 * @param {String} path
 93 * @return {Boolean}
 94 * @api private
 95 */
 96
 97Layer.prototype.match = function match(path) {
 98  if (path == null) {
 99    // no path, nothing matches
100    this.params = undefined;
101    this.path = undefined;
102    return false;
103  }
104
105  if (this.regexp.fast_slash) {
106    // fast path non-ending match for / (everything matches)
107    this.params = {};
108    this.path = '';
109    return true;
110  }
111
112  var m = this.regexp.exec(path);
113
114  if (!m) {
115    this.params = undefined;
116    this.path = undefined;
117    return false;
118  }
119
120  // store values
121  this.params = {};
122  this.path = m[0];
123
124  var keys = this.keys;
125  var params = this.params;
126  var prop;
127  var n = 0;
128  var key;
129  var val;
130
131  for (var i = 1, len = m.length; i < len; ++i) {
132    key = keys[i - 1];
133    prop = key
134      ? key.name
135      : n++;
136    val = decode_param(m[i]);
137
138    if (val !== undefined || !(hasOwnProperty.call(params, prop))) {
139      params[prop] = val;
140    }
141  }
142
143  return true;
144};
145
146/**
147 * Decode param value.
148 *
149 * @param {string} val
150 * @return {string}
151 * @api private
152 */
153
154function decode_param(val){
155  if (typeof val !== 'string') {
156    return val;
157  }
158
159  try {
160    return decodeURIComponent(val);
161  } catch (e) {
162    var err = new TypeError("Failed to decode param '" + val + "'");
163    err.status = 400;
164    throw err;
165  }
166}