mime.js (2726B)
1 var path = require('path'); 2 var fs = require('fs'); 3 4 function 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 */ 21 Mime.prototype.define = function (map) { 22 for (var type in map) { 23 var exts = map[type]; 24 for (var i = 0; i < exts.length; i++) { 25 if (process.env.DEBUG_MIME && this.types[exts[i]]) { 26 console.warn((this._loading || "define()").replace(/.*\//, ''), 'changes "' + exts[i] + '" extension type from ' + 27 this.types[exts[i]] + ' to ' + type); 28 } 29 30 this.types[exts[i]] = type; 31 } 32 33 // Default extension is the first one we encounter 34 if (!this.extensions[type]) { 35 this.extensions[type] = exts[0]; 36 } 37 } 38 }; 39 40 /** 41 * Load an Apache2-style ".types" file 42 * 43 * This may be called multiple times (it's expected). Where files declare 44 * overlapping types/extensions, the last file wins. 45 * 46 * @param file (String) path of file to load. 47 */ 48 Mime.prototype.load = function(file) { 49 this._loading = file; 50 // Read file and split into lines 51 var map = {}, 52 content = fs.readFileSync(file, 'ascii'), 53 lines = content.split(/[\r\n]+/); 54 55 lines.forEach(function(line) { 56 // Clean up whitespace/comments, and split into fields 57 var fields = line.replace(/\s*#.*|^\s*|\s*$/g, '').split(/\s+/); 58 map[fields.shift()] = fields; 59 }); 60 61 this.define(map); 62 63 this._loading = null; 64 }; 65 66 /** 67 * Lookup a mime type based on extension 68 */ 69 Mime.prototype.lookup = function(path, fallback) { 70 var ext = path.replace(/^.*[\.\/\\]/, '').toLowerCase(); 71 72 return this.types[ext] || fallback || this.default_type; 73 }; 74 75 /** 76 * Return file extension associated with a mime type 77 */ 78 Mime.prototype.extension = function(mimeType) { 79 var type = mimeType.match(/^\s*([^;\s]*)(?:;|\s|$)/)[1].toLowerCase(); 80 return this.extensions[type]; 81 }; 82 83 // Default instance 84 var mime = new Mime(); 85 86 // Define built-in types 87 mime.define(require('./types.json')); 88 89 // Default type 90 mime.default_type = mime.lookup('bin'); 91 92 // 93 // Additional API specific to the default instance 94 // 95 96 mime.Mime = Mime; 97 98 /** 99 * Lookup a charset based on mime type. 100 */ 101 mime.charsets = { 102 lookup: function(mimeType, fallback) { 103 // Assume text types are utf8 104 return (/^text\/|^application\/(javascript|json)/).test(mimeType) ? 'UTF-8' : fallback; 105 } 106 }; 107 108 module.exports = mime;