1:mod:`mimetypes` --- Map filenames to MIME types
2================================================
3
4.. module:: mimetypes
5   :synopsis: Mapping of filename extensions to MIME types.
6.. sectionauthor:: Fred L. Drake, Jr. <fdrake@acm.org>
7
8
9.. index:: pair: MIME; content type
10
11**Source code:** :source:`Lib/mimetypes.py`
12
13--------------
14
15The :mod:`mimetypes` module converts between a filename or URL and the MIME type
16associated with the filename extension.  Conversions are provided from filename
17to MIME type and from MIME type to filename extension; encodings are not
18supported for the latter conversion.
19
20The module provides one class and a number of convenience functions. The
21functions are the normal interface to this module, but some applications may be
22interested in the class as well.
23
24The functions described below provide the primary interface for this module.  If
25the module has not been initialized, they will call :func:`init` if they rely on
26the information :func:`init` sets up.
27
28
29.. function:: guess_type(url, strict=True)
30
31   .. index:: pair: MIME; headers
32
33   Guess the type of a file based on its filename or URL, given by *url*.  The
34   return value is a tuple ``(type, encoding)`` where *type* is ``None`` if the
35   type can't be guessed (missing or unknown suffix) or a string of the form
36   ``'type/subtype'``, usable for a MIME :mailheader:`content-type` header.
37
38   *encoding* is ``None`` for no encoding or the name of the program used to encode
39   (e.g. :program:`compress` or :program:`gzip`). The encoding is suitable for use
40   as a :mailheader:`Content-Encoding` header, **not** as a
41   :mailheader:`Content-Transfer-Encoding` header. The mappings are table driven.
42   Encoding suffixes are case sensitive; type suffixes are first tried case
43   sensitively, then case insensitively.
44
45   The optional *strict* argument is a flag specifying whether the list of known MIME types
46   is limited to only the official types `registered with IANA
47   <https://www.iana.org/assignments/media-types/media-types.xhtml>`_.
48   When *strict* is ``True`` (the default), only the IANA types are supported; when
49   *strict* is ``False``, some additional non-standard but commonly used MIME types
50   are also recognized.
51
52
53.. function:: guess_all_extensions(type, strict=True)
54
55   Guess the extensions for a file based on its MIME type, given by *type*. The
56   return value is a list of strings giving all possible filename extensions,
57   including the leading dot (``'.'``).  The extensions are not guaranteed to have
58   been associated with any particular data stream, but would be mapped to the MIME
59   type *type* by :func:`guess_type`.
60
61   The optional *strict* argument has the same meaning as with the :func:`guess_type` function.
62
63
64.. function:: guess_extension(type, strict=True)
65
66   Guess the extension for a file based on its MIME type, given by *type*. The
67   return value is a string giving a filename extension, including the leading dot
68   (``'.'``).  The extension is not guaranteed to have been associated with any
69   particular data stream, but would be mapped to the MIME type *type* by
70   :func:`guess_type`.  If no extension can be guessed for *type*, ``None`` is
71   returned.
72
73   The optional *strict* argument has the same meaning as with the :func:`guess_type` function.
74
75Some additional functions and data items are available for controlling the
76behavior of the module.
77
78
79.. function:: init(files=None)
80
81   Initialize the internal data structures.  If given, *files* must be a sequence
82   of file names which should be used to augment the default type map.  If omitted,
83   the file names to use are taken from :const:`knownfiles`; on Windows, the
84   current registry settings are loaded.  Each file named in *files* or
85   :const:`knownfiles` takes precedence over those named before it.  Calling
86   :func:`init` repeatedly is allowed.
87
88   Specifying an empty list for *files* will prevent the system defaults from
89   being applied: only the well-known values will be present from a built-in list.
90
91   .. versionchanged:: 2.7
92      Previously, Windows registry settings were ignored.
93
94
95.. function:: read_mime_types(filename)
96
97   Load the type map given in the file *filename*, if it exists.  The type map is
98   returned as a dictionary mapping filename extensions, including the leading dot
99   (``'.'``), to strings of the form ``'type/subtype'``.  If the file *filename*
100   does not exist or cannot be read, ``None`` is returned.
101
102
103.. function:: add_type(type, ext, strict=True)
104
105   Add a mapping from the MIME type *type* to the extension *ext*. When the
106   extension is already known, the new type will replace the old one. When the type
107   is already known the extension will be added to the list of known extensions.
108
109   When *strict* is ``True`` (the default), the mapping will be added to the
110   official MIME types, otherwise to the non-standard ones.
111
112
113.. data:: inited
114
115   Flag indicating whether or not the global data structures have been initialized.
116   This is set to ``True`` by :func:`init`.
117
118
119.. data:: knownfiles
120
121   .. index:: single: file; mime.types
122
123   List of type map file names commonly installed.  These files are typically named
124   :file:`mime.types` and are installed in different locations by different
125   packages.
126
127
128.. data:: suffix_map
129
130   Dictionary mapping suffixes to suffixes.  This is used to allow recognition of
131   encoded files for which the encoding and the type are indicated by the same
132   extension.  For example, the :file:`.tgz` extension is mapped to :file:`.tar.gz`
133   to allow the encoding and type to be recognized separately.
134
135
136.. data:: encodings_map
137
138   Dictionary mapping filename extensions to encoding types.
139
140
141.. data:: types_map
142
143   Dictionary mapping filename extensions to MIME types.
144
145
146.. data:: common_types
147
148   Dictionary mapping filename extensions to non-standard, but commonly found MIME
149   types.
150
151
152An example usage of the module::
153
154   >>> import mimetypes
155   >>> mimetypes.init()
156   >>> mimetypes.knownfiles
157   ['/etc/mime.types', '/etc/httpd/mime.types', ... ]
158   >>> mimetypes.suffix_map['.tgz']
159   '.tar.gz'
160   >>> mimetypes.encodings_map['.gz']
161   'gzip'
162   >>> mimetypes.types_map['.tgz']
163   'application/x-tar-gz'
164
165
166.. _mimetypes-objects:
167
168MimeTypes Objects
169-----------------
170
171The :class:`MimeTypes` class may be useful for applications which may want more
172than one MIME-type database; it provides an interface similar to the one of the
173:mod:`mimetypes` module.
174
175
176.. class:: MimeTypes(filenames=(), strict=True)
177
178   This class represents a MIME-types database.  By default, it provides access to
179   the same database as the rest of this module. The initial database is a copy of
180   that provided by the module, and may be extended by loading additional
181   :file:`mime.types`\ -style files into the database using the :meth:`read` or
182   :meth:`readfp` methods.  The mapping dictionaries may also be cleared before
183   loading additional data if the default data is not desired.
184
185   The optional *filenames* parameter can be used to cause additional files to be
186   loaded "on top" of the default database.
187
188
189   .. attribute:: MimeTypes.suffix_map
190
191      Dictionary mapping suffixes to suffixes.  This is used to allow recognition of
192      encoded files for which the encoding and the type are indicated by the same
193      extension.  For example, the :file:`.tgz` extension is mapped to :file:`.tar.gz`
194      to allow the encoding and type to be recognized separately.  This is initially a
195      copy of the global :data:`suffix_map` defined in the module.
196
197
198   .. attribute:: MimeTypes.encodings_map
199
200      Dictionary mapping filename extensions to encoding types.  This is initially a
201      copy of the global :data:`encodings_map` defined in the module.
202
203
204   .. attribute:: MimeTypes.types_map
205
206      Tuple containing two dictionaries, mapping filename extensions to MIME types:
207      the first dictionary is for the non-standards types and the second one is for
208      the standard types. They are initialized by :data:`common_types` and
209      :data:`types_map`.
210
211
212   .. attribute:: MimeTypes.types_map_inv
213
214      Tuple containing two dictionaries, mapping MIME types to a list of filename
215      extensions: the first dictionary is for the non-standards types and the
216      second one is for the standard types. They are initialized by
217      :data:`common_types` and :data:`types_map`.
218
219
220   .. method:: MimeTypes.guess_extension(type, strict=True)
221
222      Similar to the :func:`guess_extension` function, using the tables stored as part
223      of the object.
224
225
226   .. method:: MimeTypes.guess_type(url, strict=True)
227
228      Similar to the :func:`guess_type` function, using the tables stored as part of
229      the object.
230
231
232   .. method:: MimeTypes.guess_all_extensions(type, strict=True)
233
234      Similar to the :func:`guess_all_extensions` function, using the tables stored
235      as part of the object.
236
237
238   .. method:: MimeTypes.read(filename, strict=True)
239
240      Load MIME information from a file named *filename*.  This uses :meth:`readfp` to
241      parse the file.
242
243      If *strict* is ``True``, information will be added to list of standard types,
244      else to the list of non-standard types.
245
246
247   .. method:: MimeTypes.readfp(fp, strict=True)
248
249      Load MIME type information from an open file *fp*.  The file must have the format of
250      the standard :file:`mime.types` files.
251
252      If *strict* is ``True``, information will be added to the list of standard
253      types, else to the list of non-standard types.
254
255
256   .. method:: MimeTypes.read_windows_registry(strict=True)
257
258      Load MIME type information from the Windows registry.  Availability: Windows.
259
260      If *strict* is ``True``, information will be added to the list of standard
261      types, else to the list of non-standard types.
262
263      .. versionadded:: 2.7
264