1 # Copyright (C) 2001-2006 Python Software Foundation

     2 # Author: Anthony Baxter

     3 # Contact: email-sig@python.org

     4 

     5 """Class representing audio/* type MIME documents."""

     6 

     7 __all__ = ['MIMEAudio']

     8 

     9 import sndhdr

    10 

    11 from cStringIO import StringIO

    12 from email import encoders

    13 from email.mime.nonmultipart import MIMENonMultipart

    14 

    15 

    16 

    17 _sndhdr_MIMEmap = {'au'  : 'basic',

    18                    'wav' :'x-wav',

    19                    'aiff':'x-aiff',

    20                    'aifc':'x-aiff',

    21                    }

    22 

    23 # There are others in sndhdr that don't have MIME types. :(

    24 # Additional ones to be added to sndhdr? midi, mp3, realaudio, wma??

    25 def _whatsnd(data):

    26     """Try to identify a sound file type.

    27 

    28     sndhdr.what() has a pretty cruddy interface, unfortunately.  This is why

    29     we re-do it here.  It would be easier to reverse engineer the Unix 'file'

    30     command and use the standard 'magic' file, as shipped with a modern Unix.

    31     """

    32     hdr = data[:512]

    33     fakefile = StringIO(hdr)

    34     for testfn in sndhdr.tests:

    35         res = testfn(hdr, fakefile)

    36         if res is not None:

    37             return _sndhdr_MIMEmap.get(res[0])

    38     return None

    39 

    40 

    41 

    42 class MIMEAudio(MIMENonMultipart):

    43     """Class for generating audio/* MIME documents."""

    44 

    45     def __init__(self, _audiodata, _subtype=None,

    46                  _encoder=encoders.encode_base64, **_params):

    47         """Create an audio/* type MIME document.

    48 

    49         _audiodata is a string containing the raw audio data.  If this data

    50         can be decoded by the standard Python `sndhdr' module, then the

    51         subtype will be automatically included in the Content-Type header.

    52         Otherwise, you can specify  the specific audio subtype via the

    53         _subtype parameter.  If _subtype is not given, and no subtype can be

    54         guessed, a TypeError is raised.

    55 

    56         _encoder is a function which will perform the actual encoding for

    57         transport of the image data.  It takes one argument, which is this

    58         Image instance.  It should use get_payload() and set_payload() to

    59         change the payload to the encoded form.  It should also add any

    60         Content-Transfer-Encoding or other headers to the message as

    61         necessary.  The default encoding is Base64.

    62 

    63         Any additional keyword arguments are passed to the base class

    64         constructor, which turns them into parameters on the Content-Type

    65         header.

    66         """

    67         if _subtype is None:

    68             _subtype = _whatsnd(_audiodata)

    69         if _subtype is None:

    70             raise TypeError('Could not find audio MIME subtype')

    71         MIMENonMultipart.__init__(self, 'audio', _subtype, **_params)

    72         self.set_payload(_audiodata)

    73         _encoder(self)