1var path = require('path');
  2var fs = require('fs');
  3
  4function Mime() {
  5  // Map of extension -> mime type
  6  this.types = Object.create(null);
  7
  8  // Map of mime type -> extension
  9  this.extensions = Object.create(null);
 10}
 11
 12/**
 13 * Define mimetype -> extension mappings.  Each key is a mime-type that maps
 14 * to an array of extensions associated with the type.  The first extension is
 15 * used as the default extension for the type.
 16 *
 17 * e.g. mime.define({'audio/ogg', ['oga', 'ogg', 'spx']});
 18 *
 19 * @param map (Object) type definitions
 20 */
 21Mime.prototype.define = function (map) {
 22  for (var type in map) {
 23    var exts = map[type];
 24
 25    for (var i = 0; i < exts.length; i++) {
 26      if (process.env.DEBUG_MIME && this.types[exts]) {
 27        console.warn(this._loading.replace(/.*\//, ''), 'changes "' + exts[i] + '" extension type from ' +
 28          this.types[exts] + ' to ' + type);
 29      }
 30
 31      this.types[exts[i]] = type;
 32    }
 33
 34    // Default extension is the first one we encounter
 35    if (!this.extensions[type]) {
 36      this.extensions[type] = exts[0];
 37    }
 38  }
 39};
 40
 41/**
 42 * Load an Apache2-style ".types" file
 43 *
 44 * This may be called multiple times (it's expected).  Where files declare
 45 * overlapping types/extensions, the last file wins.
 46 *
 47 * @param file (String) path of file to load.
 48 */
 49Mime.prototype.load = function(file) {
 50
 51  this._loading = file;
 52  // Read file and split into lines
 53  var map = {},
 54      content = fs.readFileSync(file, 'ascii'),
 55      lines = content.split(/[\r\n]+/);
 56
 57  lines.forEach(function(line) {
 58    // Clean up whitespace/comments, and split into fields
 59    var fields = line.replace(/\s*#.*|^\s*|\s*$/g, '').split(/\s+/);
 60    map[fields.shift()] = fields;
 61  });
 62
 63  this.define(map);
 64
 65  this._loading = null;
 66};
 67
 68/**
 69 * Lookup a mime type based on extension
 70 */
 71Mime.prototype.lookup = function(path, fallback) {
 72  var ext = path.replace(/.*[\.\/\\]/, '').toLowerCase();
 73
 74  return this.types[ext] || fallback || this.default_type;
 75};
 76
 77/**
 78 * Return file extension associated with a mime type
 79 */
 80Mime.prototype.extension = function(mimeType) {
 81  var type = mimeType.match(/^\s*([^;\s]*)(?:;|\s|$)/)[1].toLowerCase();
 82  return this.extensions[type];
 83};
 84
 85// Default instance
 86var mime = new Mime();
 87
 88// Load local copy of
 89// http://svn.apache.org/repos/asf/httpd/httpd/trunk/docs/conf/mime.types
 90mime.load(path.join(__dirname, 'types/mime.types'));
 91
 92// Load additional types from node.js community
 93mime.load(path.join(__dirname, 'types/node.types'));
 94
 95// Default type
 96mime.default_type = mime.lookup('bin');
 97
 98//
 99// Additional API specific to the default instance
100//
101
102mime.Mime = Mime;
103
104/**
105 * Lookup a charset based on mime type.
106 */
107mime.charsets = {
108  lookup: function(mimeType, fallback) {
109    // Assume text types are utf8
110    return (/^text\//).test(mimeType) ? 'UTF-8' : fallback;
111  }
112};
113
114module.exports = mime;