1
 2var db = require('mime-db')
 3
 4// types[extension] = type
 5exports.types = Object.create(null)
 6// extensions[type] = [extensions]
 7exports.extensions = Object.create(null)
 8
 9Object.keys(db).forEach(function (name) {
10  var mime = db[name]
11  var exts = mime.extensions
12  if (!exts || !exts.length) return
13  exports.extensions[name] = exts
14  exts.forEach(function (ext) {
15    exports.types[ext] = name
16  })
17})
18
19exports.lookup = function (string) {
20  if (!string || typeof string !== "string") return false
21  // remove any leading paths, though we should just use path.basename
22  string = string.replace(/.*[\.\/\\]/, '').toLowerCase()
23  if (!string) return false
24  return exports.types[string] || false
25}
26
27exports.extension = function (type) {
28  if (!type || typeof type !== "string") return false
29  // to do: use media-typer
30  type = type.match(/^\s*([^;\s]*)(?:;|\s|$)/)
31  if (!type) return false
32  var exts = exports.extensions[type[1].toLowerCase()]
33  if (!exts || !exts.length) return false
34  return exts[0]
35}
36
37// type has to be an exact mime type
38exports.charset = function (type) {
39  var mime = db[type]
40  if (mime && mime.charset) return mime.charset
41
42  // default text/* to utf-8
43  if (/^text\//.test(type)) return 'UTF-8'
44
45  return false
46}
47
48// backwards compatibility
49exports.charsets = {
50  lookup: exports.charset
51}
52
53// to do: maybe use set-type module or something
54exports.contentType = function (type) {
55  if (!type || typeof type !== "string") return false
56  if (!~type.indexOf('/')) type = exports.lookup(type)
57  if (!type) return false
58  if (!~type.indexOf('charset')) {
59    var charset = exports.charset(type)
60    if (charset) type += '; charset=' + charset.toLowerCase()
61  }
62  return type
63}