1 :mod:`mailcap` --- Mailcap file handling 2 ======================================== 3 4 .. module:: mailcap 5 :synopsis: Mailcap file handling. 6 7 **Source code:** :source:`Lib/mailcap.py` 8 9 -------------- 10 11 Mailcap files are used to configure how MIME-aware applications such as mail 12 readers and Web browsers react to files with different MIME types. (The name 13 "mailcap" is derived from the phrase "mail capability".) For example, a mailcap 14 file might contain a line like ``video/mpeg; xmpeg %s``. Then, if the user 15 encounters an email message or Web document with the MIME type 16 :mimetype:`video/mpeg`, ``%s`` will be replaced by a filename (usually one 17 belonging to a temporary file) and the :program:`xmpeg` program can be 18 automatically started to view the file. 19 20 The mailcap format is documented in :rfc:`1524`, "A User Agent Configuration 21 Mechanism For Multimedia Mail Format Information," but is not an Internet 22 standard. However, mailcap files are supported on most Unix systems. 23 24 25 .. function:: findmatch(caps, MIMEtype[, key[, filename[, plist]]]) 26 27 Return a 2-tuple; the first element is a string containing the command line to 28 be executed (which can be passed to :func:`os.system`), and the second element 29 is the mailcap entry for a given MIME type. If no matching MIME type can be 30 found, ``(None, None)`` is returned. 31 32 *key* is the name of the field desired, which represents the type of activity to 33 be performed; the default value is 'view', since in the most common case you 34 simply want to view the body of the MIME-typed data. Other possible values 35 might be 'compose' and 'edit', if you wanted to create a new body of the given 36 MIME type or alter the existing body data. See :rfc:`1524` for a complete list 37 of these fields. 38 39 *filename* is the filename to be substituted for ``%s`` in the command line; the 40 default value is ``'/dev/null'`` which is almost certainly not what you want, so 41 usually you'll override it by specifying a filename. 42 43 *plist* can be a list containing named parameters; the default value is simply 44 an empty list. Each entry in the list must be a string containing the parameter 45 name, an equals sign (``'='``), and the parameter's value. Mailcap entries can 46 contain named parameters like ``%{foo}``, which will be replaced by the value 47 of the parameter named 'foo'. For example, if the command line ``showpartial 48 %{id} %{number} %{total}`` was in a mailcap file, and *plist* was set to 49 ``['id=1', 'number=2', 'total=3']``, the resulting command line would be 50 ``'showpartial 1 2 3'``. 51 52 In a mailcap file, the "test" field can optionally be specified to test some 53 external condition (such as the machine architecture, or the window system in 54 use) to determine whether or not the mailcap line applies. :func:`findmatch` 55 will automatically check such conditions and skip the entry if the check fails. 56 57 58 .. function:: getcaps() 59 60 Returns a dictionary mapping MIME types to a list of mailcap file entries. This 61 dictionary must be passed to the :func:`findmatch` function. An entry is stored 62 as a list of dictionaries, but it shouldn't be necessary to know the details of 63 this representation. 64 65 The information is derived from all of the mailcap files found on the system. 66 Settings in the user's mailcap file :file:`$HOME/.mailcap` will override 67 settings in the system mailcap files :file:`/etc/mailcap`, 68 :file:`/usr/etc/mailcap`, and :file:`/usr/local/etc/mailcap`. 69 70 An example usage:: 71 72 >>> import mailcap 73 >>> d = mailcap.getcaps() 74 >>> mailcap.findmatch(d, 'video/mpeg', filename='tmp1223') 75 ('xmpeg tmp1223', {'view': 'xmpeg %s'}) 76 77
