1:mod:`mimetypes` --- Map filenames to MIME types
2================================================
3
4.. module:: mimetypes
5   :synopsis: Mapping of filename extensions to MIME types.
6
7.. sectionauthor:: Fred L. Drake, Jr. <fdrake@acm.org>
8
9**Source code:** :source:`Lib/mimetypes.py`
10
11.. index:: pair: MIME; content type
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, path or URL, given by *url*.
34   URL can be a string or a :term:`path-like object`.
35
36   The return value is a tuple ``(type, encoding)`` where *type* is ``None`` if the
37   type can't be guessed (missing or unknown suffix) or a string of the form
38   ``'type/subtype'``, usable for a MIME :mailheader:`content-type` header.
39
40   *encoding* is ``None`` for no encoding or the name of the program used to encode
41   (e.g. :program:`compress` or :program:`gzip`). The encoding is suitable for use
42   as a :mailheader:`Content-Encoding` header, **not** as a
43   :mailheader:`Content-Transfer-Encoding` header. The mappings are table driven.
44   Encoding suffixes are case sensitive; type suffixes are first tried case
45   sensitively, then case insensitively.
46
47   The optional *strict* argument is a flag specifying whether the list of known MIME types
48   is limited to only the official types `registered with IANA
49   <https://www.iana.org/assignments/media-types/media-types.xhtml>`_.
50   When *strict* is ``True`` (the default), only the IANA types are supported; when
51   *strict* is ``False``, some additional non-standard but commonly used MIME types
52   are also recognized.
53
54   .. versionchanged:: 3.8
55      Added support for url being a :term:`path-like object`.
56
57
58.. function:: guess_all_extensions(type, strict=True)
59
60   Guess the extensions for a file based on its MIME type, given by *type*. The
61   return value is a list of strings giving all possible filename extensions,
62   including the leading dot (``'.'``).  The extensions are not guaranteed to have
63   been associated with any particular data stream, but would be mapped to the MIME
64   type *type* by :func:`guess_type`.
65
66   The optional *strict* argument has the same meaning as with the :func:`guess_type` function.
67
68
69.. function:: guess_extension(type, strict=True)
70
71   Guess the extension for a file based on its MIME type, given by *type*. The
72   return value is a string giving a filename extension, including the leading dot
73   (``'.'``).  The extension is not guaranteed to have been associated with any
74   particular data stream, but would be mapped to the MIME type *type* by
75   :func:`guess_type`.  If no extension can be guessed for *type*, ``None`` is
76   returned.
77
78   The optional *strict* argument has the same meaning as with the :func:`guess_type` function.
79
80Some additional functions and data items are available for controlling the
81behavior of the module.
82
83
84.. function:: init(files=None)
85
86   Initialize the internal data structures.  If given, *files* must be a sequence
87   of file names which should be used to augment the default type map.  If omitted,
88   the file names to use are taken from :const:`knownfiles`; on Windows, the
89   current registry settings are loaded.  Each file named in *files* or
90   :const:`knownfiles` takes precedence over those named before it.  Calling
91   :func:`init` repeatedly is allowed.
92
93   Specifying an empty list for *files* will prevent the system defaults from
94   being applied: only the well-known values will be present from a built-in list.
95
96   If *files* is ``None`` the internal data structure is completely rebuilt to its
97   initial default value. This is a stable operation and will produce the same results
98   when called multiple times.
99
100   .. versionchanged:: 3.2
101      Previously, Windows registry settings were ignored.
102
103
104.. function:: read_mime_types(filename)
105
106   Load the type map given in the file *filename*, if it exists.  The type map is
107   returned as a dictionary mapping filename extensions, including the leading dot
108   (``'.'``), to strings of the form ``'type/subtype'``.  If the file *filename*
109   does not exist or cannot be read, ``None`` is returned.
110
111
112.. function:: add_type(type, ext, strict=True)
113
114   Add a mapping from the MIME type *type* to the extension *ext*. When the
115   extension is already known, the new type will replace the old one. When the type
116   is already known the extension will be added to the list of known extensions.
117
118   When *strict* is ``True`` (the default), the mapping will be added to the
119   official MIME types, otherwise to the non-standard ones.
120
121
122.. data:: inited
123
124   Flag indicating whether or not the global data structures have been initialized.
125   This is set to ``True`` by :func:`init`.
126
127
128.. data:: knownfiles
129
130   .. index:: single: file; mime.types
131
132   List of type map file names commonly installed.  These files are typically named
133   :file:`mime.types` and are installed in different locations by different
134   packages.
135
136
137.. data:: suffix_map
138
139   Dictionary mapping suffixes to suffixes.  This is used to allow recognition of
140   encoded files for which the encoding and the type are indicated by the same
141   extension.  For example, the :file:`.tgz` extension is mapped to :file:`.tar.gz`
142   to allow the encoding and type to be recognized separately.
143
144
145.. data:: encodings_map
146
147   Dictionary mapping filename extensions to encoding types.
148
149
150.. data:: types_map
151
152   Dictionary mapping filename extensions to MIME types.
153
154
155.. data:: common_types
156
157   Dictionary mapping filename extensions to non-standard, but commonly found MIME
158   types.
159
160
161An example usage of the module::
162
163   >>> import mimetypes
164   >>> mimetypes.init()
165   >>> mimetypes.knownfiles
166   ['/etc/mime.types', '/etc/httpd/mime.types', ... ]
167   >>> mimetypes.suffix_map['.tgz']
168   '.tar.gz'
169   >>> mimetypes.encodings_map['.gz']
170   'gzip'
171   >>> mimetypes.types_map['.tgz']
172   'application/x-tar-gz'
173
174
175.. _mimetypes-objects:
176
177MimeTypes Objects
178-----------------
179
180The :class:`MimeTypes` class may be useful for applications which may want more
181than one MIME-type database; it provides an interface similar to the one of the
182:mod:`mimetypes` module.
183
184
185.. class:: MimeTypes(filenames=(), strict=True)
186
187   This class represents a MIME-types database.  By default, it provides access to
188   the same database as the rest of this module. The initial database is a copy of
189   that provided by the module, and may be extended by loading additional
190   :file:`mime.types`\ -style files into the database using the :meth:`read` or
191   :meth:`readfp` methods.  The mapping dictionaries may also be cleared before
192   loading additional data if the default data is not desired.
193
194   The optional *filenames* parameter can be used to cause additional files to be
195   loaded "on top" of the default database.
196
197
198   .. attribute:: MimeTypes.suffix_map
199
200      Dictionary mapping suffixes to suffixes.  This is used to allow recognition of
201      encoded files for which the encoding and the type are indicated by the same
202      extension.  For example, the :file:`.tgz` extension is mapped to :file:`.tar.gz`
203      to allow the encoding and type to be recognized separately.  This is initially a
204      copy of the global :data:`suffix_map` defined in the module.
205
206
207   .. attribute:: MimeTypes.encodings_map
208
209      Dictionary mapping filename extensions to encoding types.  This is initially a
210      copy of the global :data:`encodings_map` defined in the module.
211
212
213   .. attribute:: MimeTypes.types_map
214
215      Tuple containing two dictionaries, mapping filename extensions to MIME types:
216      the first dictionary is for the non-standards types and the second one is for
217      the standard types. They are initialized by :data:`common_types` and
218      :data:`types_map`.
219
220
221   .. attribute:: MimeTypes.types_map_inv
222
223      Tuple containing two dictionaries, mapping MIME types to a list of filename
224      extensions: the first dictionary is for the non-standards types and the
225      second one is for the standard types. They are initialized by
226      :data:`common_types` and :data:`types_map`.
227
228
229   .. method:: MimeTypes.guess_extension(type, strict=True)
230
231      Similar to the :func:`guess_extension` function, using the tables stored as part
232      of the object.
233
234
235   .. method:: MimeTypes.guess_type(url, strict=True)
236
237      Similar to the :func:`guess_type` function, using the tables stored as part of
238      the object.
239
240
241   .. method:: MimeTypes.guess_all_extensions(type, strict=True)
242
243      Similar to the :func:`guess_all_extensions` function, using the tables stored
244      as part of the object.
245
246
247   .. method:: MimeTypes.read(filename, strict=True)
248
249      Load MIME information from a file named *filename*.  This uses :meth:`readfp` to
250      parse the file.
251
252      If *strict* is ``True``, information will be added to list of standard types,
253      else to the list of non-standard types.
254
255
256   .. method:: MimeTypes.readfp(fp, strict=True)
257
258      Load MIME type information from an open file *fp*.  The file must have the format of
259      the standard :file:`mime.types` files.
260
261      If *strict* is ``True``, information will be added to the list of standard
262      types, else to the list of non-standard types.
263
264
265   .. method:: MimeTypes.read_windows_registry(strict=True)
266
267      Load MIME type information from the Windows registry.
268
269      .. availability:: Windows.
270
271      If *strict* is ``True``, information will be added to the list of standard
272      types, else to the list of non-standard types.
273
274      .. versionadded:: 3.2
275