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<H1><A NAME="SECTION0014700000000000000000">
12.7 <tt class="module">mimetypes</tt> --
Map filenames to MIME types</A>
</H1>
<P>
<P>
<a name="l2h-2936"> </a>
<P>
The <tt class="module">mimetypes</tt> 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.
<P>
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.
<P>
The functions described below provide the primary interface for this
module. If the module has not been initialized, they will call
<tt class="function">init()</tt> if they rely on the information <tt class="function">init()</tt>
sets up.
<P>
<dl><dt><b><a name="l2h-2925"><tt class="function">guess_type</tt></a></b>(<var>filename</var><big>[</big><var>, strict</var><big>]</big>)
<dd>
Guess the type of a file based on its filename or URL, given by
<var>filename</var>. The return value is a tuple <code>(<var>type</var>,
<var>encoding</var>)</code> where <var>type</var> is <code>None</code> if the type can't be
guessed (missing or unknown suffix) or a string of the form
<code>'<var>type</var>/<var>subtype</var>'</code>, usable for a MIME
<span class="mailheader">content-type:</span> header<a name="l2h-2937"> </a>.
<P>
<var>encoding</var> is <code>None</code> for no encoding or the name of the
program used to encode (e.g. <b class="program">compress</b> or <b class="program">gzip</b>).
The encoding is suitable for use as a <span class="mailheader">Content-Encoding:</span>
header, <i>not</i> as a <span class="mailheader">Content-Transfer-Encoding:</span> header.
The mappings are table driven. Encoding suffixes are case sensitive;
type suffixes are first tried case sensitively, then case
insensitively.
<P>
Optional <var>strict</var> is a flag specifying whether the list of known
MIME types is limited to only the official types <a class="ulink" href="http://www.isi.edu/in-notes/iana/assignments/media-types"
>registered
with IANA</a>
are recognized. When <var>strict</var> is true (the default), only the
IANA types are supported; when <var>strict</var> is false, some additional
non-standard but commonly used MIME types are also recognized.
</dl>
<P>
<dl><dt><b><a name="l2h-2926"><tt class="function">guess_extension</tt></a></b>(<var>type</var><big>[</big><var>, strict</var><big>]</big>)
<dd>
Guess the extension for a file based on its MIME type, given by
<var>type</var>.
The return value is a string giving a filename extension, including the
leading dot ("<tt class="character">.</tt>"). The extension is not guaranteed to have been
associated with any particular data stream, but would be mapped to the
MIME type <var>type</var> by <tt class="function">guess_type()</tt>. If no extension can
be guessed for <var>type</var>, <code>None</code> is returned.
<P>
Optional <var>strict</var> has the same meaning as with the
<tt class="function">guess_type()</tt> function.
</dl>
<P>
Some additional functions and data items are available for controlling
the behavior of the module.
<P>
<dl><dt><b><a name="l2h-2927"><tt class="function">init</tt></a></b>(<big>[</big><var>files</var><big>]</big>)
<dd>
Initialize the internal data structures. If given, <var>files</var> 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
<tt class="constant">knownfiles</tt>. Each file named in <var>files</var> or
<tt class="constant">knownfiles</tt> takes precedence over those named before it.
Calling <tt class="function">init()</tt> repeatedly is allowed.
</dl>
<P>
<dl><dt><b><a name="l2h-2928"><tt class="function">read_mime_types</tt></a></b>(<var>filename</var>)
<dd>
Load the type map given in the file <var>filename</var>, if it exists. The
type map is returned as a dictionary mapping filename extensions,
including the leading dot ("<tt class="character">.</tt>"), to strings of the form
<code>'<var>type</var>/<var>subtype</var>'</code>. If the file <var>filename</var> does
not exist or cannot be read, <code>None</code> is returned.
</dl>
<P>
<dl><dt><b><a name="l2h-2929"><tt>inited</tt></a></b>
<dd>
Flag indicating whether or not the global data structures have been
initialized. This is set to true by <tt class="function">init()</tt>.
</dl>
<P>
<dl><dt><b><a name="l2h-2930"><tt>knownfiles</tt></a></b>
<dd>
List of type map file names commonly installed. These files are
typically named <span class="file">mime.types</span> and are installed in different
locations by different packages.<a name="l2h-2938"> </a></dl>
<P>
<dl><dt><b><a name="l2h-2931"><tt>suffix_map</tt></a></b>
<dd>
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 <span class="file">.tgz</span>
extension is mapped to <span class="file">.tar.gz</span> to allow the encoding and type
to be recognized separately.
</dl>
<P>
<dl><dt><b><a name="l2h-2932"><tt>encodings_map</tt></a></b>
<dd>
Dictionary mapping filename extensions to encoding types.
</dl>
<P>
<dl><dt><b><a name="l2h-2933"><tt>types_map</tt></a></b>
<dd>
Dictionary mapping filename extensions to MIME types.
</dl>
<P>
<dl><dt><b><a name="l2h-2934"><tt>common_types</tt></a></b>
<dd>
Dictionary mapping filename extensions to non-standard, but commonly
found MIME types.
</dl>
<P>
The <tt class="class">MimeTypes</tt> class may be useful for applications which may
want more than one MIME-type database:
<P>
<dl><dt><b><span class="typelabel">class</span> <a name="l2h-2935"><tt class="class">MimeTypes</tt></a></b>(<big>[</big><var>filenames</var><big>]</big>)
<dd>
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 <span class="file">mime.types</span>-style files
into the database using the <tt class="method">read()</tt> or <tt class="method">readfp()</tt>
methods. The mapping dictionaries may also be cleared before
loading additional data if the default data is not desired.
<P>
The optional <var>filenames</var> parameter can be used to cause
additional files to be loaded ``on top'' of the default database.
<P>
<span class="versionnote">New in version 2.2.</span>
</dl>
<P>
<p><hr>
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<LI><A href="mimetypes-objects.html">12.7.1 MimeTypes Objects</a>
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<span class="release-info">Release 2.2, documentation updated on December 21, 2001.</span>
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