\section{Standard Module \module{mimetypes}}

\label{module-mimetypes}

\stmodindex{mimetypes}

\indexii{MIME}{content type}

The \module{mimetypes} 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 later conversion.

The functions described below provide the primary interface for this

module. If the module has not been initialized, they will call the

\function{init()}.

\begin{funcdesc}{guess_type}{filename}

Guess the type of a file based on its filename or URL, given by

\var{filename}.

The return value is a tuple \code{(\var{type}, \var{encoding})} where

\var{type} is \code{None} if the type can't be guessed (no or unknown

suffix) or a string of the form \code{'\var{type}/\var{subtype}'},

usable for a MIME \code{content-type} header\indexii{MIME}{headers}; and

encoding is \code{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 \code{content-encoding} header,

\emph{not} as a \code{content-transfer-encoding} header. The mappings

are table driven. Encoding suffixes are case sensitive; type suffixes

are first tried case sensitive, then case insensitive.

\end{funcdesc}

\begin{funcdesc}{guess_extension}{type}

Guess the extension for a file based on its MIME type, given by

\var{type}.

The return value is a string giving a filename extension, including the

leading dot (\character{.}). The extension is not guaranteed to have been

associated with any particular data stream, but would be mapped to the

MIME type \var{type} by \function{guess_type()}. If no extension can

be guessed for \var{type}, \code{None} is returned.

\end{funcdesc}

Some additional functions and data items are available for controlling

the behavior of the module.

\begin{funcdesc}{init}{\optional{files}}

Initialize the internal data structures. If given, \var{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

\code{knownfiles}. Each file named in \var{files} or

\code{knownfiles} takes precedence over those named before it.

Calling \function{init()} repeatedly is allowed.

\end{funcdesc}

\begin{funcdesc}{read_mime_types}{filename}

Load the type map given in the file \var{filename}, if it exists. The

type map is returned as a dictionary mapping filename extensions,

including the leading dot (\character{.}), to strings of the form

\code{'\var{type}/\var{subtype}'}. If the file \var{filename} does

not exist or cannot be read, \code{None} is returned.

\end{funcdesc}

\begin{datadesc}{inited}

Flag indicating whether or not the global data structures have been

initialized. This is set to true by \function{init()}.

\end{datadesc}

\begin{datadesc}{knownfiles}

List of type map file names commonly installed. These files are

typically names \file{mime.types} and are installed in different

locations by different packages.%

\index{file!mime.types}

\end{datadesc}

\begin{datadesc}{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.

\end{datadesc}

\begin{datadesc}{encodings_map}

Dictionary mapping filename extensions to encoding types.

\end{datadesc}

\begin{datadesc}{types_map}

Dictionary mapping filename extensions to MIME types.

\end{datadesc}