:mod:`!mimetypes` --- Map filenames to MIME types
=================================================

.. module:: mimetypes
   :synopsis: Mapping of filename extensions to MIME types.

**Source code:** :source:`Lib/mimetypes.py`

.. index:: pair: MIME; content type

--------------

The :mod:`!mimetypes` module converts between a filename or URL and the MIME type
associated with the filename extension.  Conversions are provided from filename
to MIME type and from MIME type to filename extension; encodings are not
supported for the latter conversion.

The module provides one class and a number of convenience functions. The
functions are the normal interface to this module, but some applications may be
interested in the class as well.

The functions described below provide the primary interface for this module.  If
the module has not been initialized, they will call :func:`init` if they rely on
the information :func:`init` sets up.


.. function:: guess_type(url, strict=True)

   .. index:: pair: MIME; headers

   Guess the type of a file based on its filename, path or URL, given by *url*.
   URL can be a string or a :term:`path-like object`.

   The return value is a tuple ``(type, encoding)`` where *type* is ``None`` if the
   type can't be guessed (missing or unknown suffix) or a string of the form
   ``'type/subtype'``, usable for a MIME :mailheader:`content-type` header.

   *encoding* is ``None`` for no encoding or the name of the program used to encode
   (e.g. :program:`compress` or :program:`gzip`). The encoding is suitable for use
   as a :mailheader:`Content-Encoding` header, **not** as a
   :mailheader:`Content-Transfer-Encoding` header. The mappings are table driven.
   Encoding suffixes are case-sensitive. Suffix mappings and type suffixes are
   first tried case-sensitively, then case-insensitively.

   The optional *strict* argument is a flag specifying whether the list of known MIME types
   is limited to only the official types `registered with IANA
   <https://www.iana.org/assignments/media-types/media-types.xhtml>`_.
   However, the behavior of this module also depends on the underlying operating
   system. Only file types recognized by the OS or explicitly registered with
   Python's internal database can be identified. When *strict* is ``True`` (the
   default), only the IANA types are supported; when *strict* is ``False``, some
   additional non-standard but commonly used MIME types are also recognized.

   .. versionchanged:: 3.8
      Added support for *url* being a :term:`path-like object`.

   .. soft-deprecated:: 3.13
      Passing a file path instead of URL.
      Use :func:`guess_file_type` for this.


.. function:: guess_file_type(path, *, strict=True)

   .. index:: pair: MIME; headers

   Guess the type of a file based on its path, given by *path*.
   Similar to the :func:`guess_type` function, but accepts a path instead of URL.
   Path can be a string, a bytes object or a :term:`path-like object`.

   .. versionadded:: 3.13


.. function:: guess_all_extensions(type, strict=True)

   Guess the extensions for a file based on its MIME type, given by *type*. The
   return value is a list of strings giving all possible filename extensions,
   including the leading dot (``'.'``).  The extensions are not guaranteed to have
   been associated with any particular data stream, but would be mapped to the MIME
   type *type* by :func:`guess_type` and :func:`guess_file_type`.

   The optional *strict* argument has the same meaning as with the :func:`guess_type` function.


.. function:: guess_extension(type, strict=True)

   Guess the extension for a file based on its MIME type, given by *type*. The
   return value is a string giving a filename extension, including the leading dot
   (``'.'``).  The extension is not guaranteed to have been associated with any
   particular data stream, but would be mapped to the MIME type *type* by
   :func:`guess_type` and :func:`guess_file_type`.
   If no extension can be guessed for *type*, ``None`` is returned.

   The optional *strict* argument has the same meaning as with the :func:`guess_type` function.

Some additional functions and data items are available for controlling the
behavior of the module.


.. function:: init(files=None)

   Initialize the internal data structures.  If given, *files* must be a sequence
   of file names which should be used to augment the default type map.  If omitted,
   the file names to use are taken from :const:`knownfiles`; on Windows, the
   current registry settings are loaded.  Each file named in *files* or
   :const:`knownfiles` takes precedence over those named before it.  Calling
   :func:`init` repeatedly is allowed.

   Specifying an empty list for *files* will prevent the system defaults from
   being applied: only the well-known values will be present from a built-in list.

   If *files* is ``None`` the internal data structure is completely rebuilt to its
   initial default value. This is a stable operation and will produce the same results
   when called multiple times.

   .. versionchanged:: 3.2
      Previously, Windows registry settings were ignored.


.. function:: read_mime_types(filename)

   Load the type map given in the file *filename*, if it exists.  The type map is
   returned as a dictionary mapping filename extensions, including the leading dot
   (``'.'``), to strings of the form ``'type/subtype'``.  If the file *filename*
   does not exist or cannot be read, ``None`` is returned.


.. function:: add_type(type, ext, strict=True)

   Add a mapping from the MIME type *type* to the extension *ext*. When the
   extension is already known, the new type will replace the old one. When the type
   is already known the extension will be added to the list of known extensions.
   Valid extensions are empty or start with a ``'.'``.

   Registered lower-case extensions are matched case-insensitively.

   When *strict* is ``True`` (the default), the mapping will be added to the
   official MIME types, otherwise to the non-standard ones.

   .. deprecated:: 3.14
      *ext* values that do not start with ``'.'`` are deprecated.

   .. versionchanged:: next
      *ext* now must start with ``'.'``. Otherwise :exc:`ValueError` is raised.



.. data:: inited

   Flag indicating whether or not the global data structures have been initialized.
   This is set to ``True`` by :func:`init`.


.. data:: knownfiles

   .. index:: single: file; mime.types

   List of type map file names commonly installed.  These files are typically named
   :file:`mime.types` and are installed in different locations by different
   packages.


.. data:: suffix_map

   Dictionary mapping suffixes to suffixes.  This is used to allow recognition of
   encoded files for which the encoding and the type are indicated by the same
   extension.  For example, the :file:`.tgz` extension is mapped to :file:`.tar.gz`
   to allow the encoding and type to be recognized separately.


.. data:: encodings_map

   Dictionary mapping filename extensions to encoding types.


.. data:: types_map

   Dictionary mapping filename extensions to MIME types.


.. data:: common_types

   Dictionary mapping filename extensions to non-standard, but commonly found MIME
   types.


An example usage of the module::

   >>> import mimetypes
   >>> mimetypes.init()
   >>> mimetypes.knownfiles
   ['/etc/mime.types', '/etc/httpd/mime.types', ... ]
   >>> mimetypes.suffix_map['.tgz']
   '.tar.gz'
   >>> mimetypes.encodings_map['.gz']
   'gzip'
   >>> mimetypes.types_map['.tgz']
   'application/x-tar-gz'


.. _mimetypes-objects:

MimeTypes objects
-----------------

The :class:`MimeTypes` class may be useful for applications which may want more
than one MIME-type database; it provides an interface similar to the one of the
:mod:`!mimetypes` module.


.. class:: MimeTypes(filenames=(), strict=True)

   This class represents a MIME-types database.  By default, it provides access to
   the same database as the rest of this module. The initial database is a copy of
   that provided by the module, and may be extended by loading additional
   :file:`mime.types`\ -style files into the database using the :meth:`read` or
   :meth:`readfp` methods.  The mapping dictionaries may also be cleared before
   loading additional data if the default data is not desired.

   The optional *filenames* parameter can be used to cause additional files to be
   loaded "on top" of the default database.


   .. attribute:: MimeTypes.suffix_map

      Dictionary mapping suffixes to suffixes.  This is used to allow recognition of
      encoded files for which the encoding and the type are indicated by the same
      extension.  For example, the :file:`.tgz` extension is mapped to :file:`.tar.gz`
      to allow the encoding and type to be recognized separately.  This is initially a
      copy of the global :data:`suffix_map` defined in the module.


   .. attribute:: MimeTypes.encodings_map

      Dictionary mapping filename extensions to encoding types.  This is initially a
      copy of the global :data:`encodings_map` defined in the module.


   .. attribute:: MimeTypes.types_map

      Tuple containing two dictionaries, mapping filename extensions to MIME types:
      the first dictionary is for the non-standards types and the second one is for
      the standard types. They are initialized by :data:`common_types` and
      :data:`types_map`.


   .. attribute:: MimeTypes.types_map_inv

      Tuple containing two dictionaries, mapping MIME types to a list of filename
      extensions: the first dictionary is for the non-standards types and the
      second one is for the standard types. They are initialized by
      :data:`common_types` and :data:`types_map`.


   .. method:: MimeTypes.guess_extension(type, strict=True)

      Similar to the :func:`guess_extension` function, using the tables stored as part
      of the object.


   .. method:: MimeTypes.guess_type(url, strict=True)

      Similar to the :func:`guess_type` function, using the tables stored as part of
      the object.


   .. method:: MimeTypes.guess_file_type(path, *, strict=True)

      Similar to the :func:`guess_file_type` function, using the tables stored
      as part of the object.

      .. versionadded:: 3.13


   .. method:: MimeTypes.guess_all_extensions(type, strict=True)

      Similar to the :func:`guess_all_extensions` function, using the tables stored
      as part of the object.


   .. method:: MimeTypes.read(filename, strict=True)

      Load MIME information from a file named *filename*.  This uses :meth:`readfp` to
      parse the file.

      If *strict* is ``True``, information will be added to list of standard types,
      else to the list of non-standard types.


   .. method:: MimeTypes.readfp(fp, strict=True)

      Load MIME type information from an open file *fp*.  The file must have the format of
      the standard :file:`mime.types` files.

      If *strict* is ``True``, information will be added to the list of standard
      types, else to the list of non-standard types.


   .. method:: MimeTypes.read_windows_registry(strict=True)

      Load MIME type information from the Windows registry.

      .. availability:: Windows.

      If *strict* is ``True``, information will be added to the list of standard
      types, else to the list of non-standard types.

      .. versionadded:: 3.2


   .. method:: MimeTypes.add_type(type, ext, strict=True)

      Add a mapping from the MIME type *type* to the extension *ext*.
      Valid extensions start with a '.' or are empty. When the
      extension is already known, the new type will replace the old one. When the type
      is already known the extension will be added to the list of known extensions.

      Registered lower-case extensions are matched case-insensitively.

      When *strict* is ``True`` (the default), the mapping will be added to the
      official MIME types, otherwise to the non-standard ones.

      .. deprecated:: 3.14
         *ext* values that do not start with ``'.'`` are deprecated.

      .. versionchanged:: next
         *ext* now must start with ``'.'``. Otherwise :exc:`ValueError` is raised.


.. _mimetypes-cli:

Command-line usage
------------------

The :mod:`!mimetypes` module can be executed as a script from the command line.

.. code-block:: sh

   python -m mimetypes [-h] [-e] [-l] type [type ...]

The following options are accepted:

.. program:: mimetypes

.. cmdoption:: -h
               --help

   Show the help message and exit.

.. cmdoption:: -e
               --extension

   Guess extension instead of type.

.. cmdoption:: -l
               --lenient

   Additionally search for some common, but non-standard types.

By default the script converts MIME types to file extensions.
However, if ``--extension`` is specified,
it converts file extensions to MIME types.

For each ``type`` entry, the script writes a line into the standard output
stream. If an unknown type occurs, it writes an error message into the
standard output stream and exits with the return code ``1``.


.. mimetypes-cli-example:

Command-line example
--------------------

Here are some examples of typical usage of the :mod:`!mimetypes` command-line
interface:

.. code-block:: console

   $ # get a MIME type by a file name
   $ python -m mimetypes filename.png
   type: image/png encoding: None

   $ # get a MIME type by a URL
   $ python -m mimetypes https://example.com/filename.txt
   type: text/plain encoding: None

   $ # get a complex MIME type
   $ python -m mimetypes filename.tar.gz
   type: application/x-tar encoding: gzip

   $ # get a MIME type for a rare file extension
   $ python -m mimetypes filename.pict
   error: media type unknown for filename.pict

   $ # now look in the extended database built into Python
   $ python -m mimetypes --lenient filename.pict
   type: image/pict encoding: None

   $ # get a file extension by a MIME type
   $ python -m mimetypes --extension text/javascript
   .js

   $ # get a file extension by a rare MIME type
   $ python -m mimetypes --extension text/xul
   error: unknown type text/xul

   $ # now look in the extended database again
   $ python -m mimetypes --extension --lenient text/xul
   .xul

   $ # try to feed an unknown file extension
   $ python -m mimetypes filename.sh filename.nc filename.xxx filename.txt
   type: application/x-sh encoding: None
   type: application/x-netcdf encoding: None
   error: media type unknown for filename.xxx
   type: text/plain encoding: None

   $ # try to feed an unknown MIME type
   $ python -m mimetypes --extension audio/aac audio/opus audio/future audio/x-wav
   .aac
   .opus
   error: unknown type audio/future
