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)