HORIZON PROJECT

var path = require('path');

var fs = require('fs');

function Mime() {

  // Map of extension -> mime type

  this.types = Object.create(null);

  // Map of mime type -> extension

  this.extensions = Object.create(null);

}

/**

 * Define mimetype -> extension mappings.  Each key is a mime-type that maps

 * to an array of extensions associated with the type.  The first extension is

 * used as the default extension for the type.

 *

 * e.g. mime.define({'audio/ogg', ['oga', 'ogg', 'spx']});

 *

 * @param map (Object) type definitions

 */

Mime.prototype.define = function (map) {

  for (var type in map) {

    var exts = map[type];

    for (var i = 0; i < exts.length; i++) {

      if (process.env.DEBUG_MIME && this.types[exts[i]]) {

        console.warn((this._loading || "define()").replace(/.*\//, ''), 'changes "' + exts[i] + '" extension type from ' +

          this.types[exts[i]] + ' to ' + type);

      }

      this.types[exts[i]] = type;

    }

    // Default extension is the first one we encounter

    if (!this.extensions[type]) {

      this.extensions[type] = exts[0];

    }

  }

};

/**

 * Load an Apache2-style ".types" file

 *

 * This may be called multiple times (it's expected).  Where files declare

 * overlapping types/extensions, the last file wins.

 *

 * @param file (String) path of file to load.

 */

Mime.prototype.load = function(file) {

  this._loading = file;

  // Read file and split into lines

  var map = {},

      content = fs.readFileSync(file, 'ascii'),

      lines = content.split(/[\r\n]+/);

  lines.forEach(function(line) {

    // Clean up whitespace/comments, and split into fields

    var fields = line.replace(/\s*#.*|^\s*|\s*$/g, '').split(/\s+/);

    map[fields.shift()] = fields;

  });

  this.define(map);

  this._loading = null;

};

/**

 * Lookup a mime type based on extension

 */

Mime.prototype.lookup = function(path, fallback) {

  var ext = path.replace(/^.*[\.\/\\]/, '').toLowerCase();

  return this.types[ext] || fallback || this.default_type;

};

/**

 * Return file extension associated with a mime type

 */

Mime.prototype.extension = function(mimeType) {

  var type = mimeType.match(/^\s*([^;\s]*)(?:;|\s|$)/)[1].toLowerCase();

  return this.extensions[type];

};

// Default instance

var mime = new Mime();

// Define built-in types

mime.define(require('./types.json'));

// Default type

mime.default_type = mime.lookup('bin');

//

// Additional API specific to the default instance

//

mime.Mime = Mime;

/**

 * Lookup a charset based on mime type.

 */

mime.charsets = {

  lookup: function(mimeType, fallback) {

    // Assume text types are utf8

    return (/^text\/|^application\/(javascript|json)/).test(mimeType) ? 'UTF-8' : fallback;

  }

};

module.exports = mime;