1 # Copyright (C) 2001-2006 Python Software Foundation
2 # Author: Barry Warsaw
3 # Contact: email-sig@python.org
4 
5 """Various types of useful iterators and generators."""
6 
7 __all__ = [
8     'body_line_iterator',
9     'typed_subpart_iterator',
10     'walk',
11     # Do not include _structure() since it's part of the debugging API.
12     ]
13 
14 import sys
15 from cStringIO import StringIO
16 
17 
18 
19 # This function will become a method of the Message class
20 def walk(self):
21     """Walk over the message tree, yielding each subpart.
22 
23     The walk is performed in depth-first order.  This method is a
24     generator.
25     """
26     yield self
27     if self.is_multipart():
28         for subpart in self.get_payload():
29             for subsubpart in subpart.walk():
30                 yield subsubpart
31 
32 
33 
34 # These two functions are imported into the Iterators.py interface module.
35 def body_line_iterator(msg, decode=False):
36     """Iterate over the parts, returning string payloads line-by-line.
37 
38     Optional decode (default False) is passed through to .get_payload().
39     """
40     for subpart in msg.walk():
41         payload = subpart.get_payload(decode=decode)
42         if isinstance(payload, basestring):
43             for line in StringIO(payload):
44                 yield line
45 
46 
47 def typed_subpart_iterator(msg, maintype='text', subtype=None):
48     """Iterate over the subparts with a given MIME type.
49 
50     Use `maintype' as the main MIME type to match against; this defaults to
51     "text".  Optional `subtype' is the MIME subtype to match against; if
52     omitted, only the main type is matched.
53     """
54     for subpart in msg.walk():
55         if subpart.get_content_maintype() == maintype:
56             if subtype is None or subpart.get_content_subtype() == subtype:
57                 yield subpart
58 
59 
60 
61 def _structure(msg, fp=None, level=0, include_default=False):
62     """A handy debugging aid"""
63     if fp is None:
64         fp = sys.stdout
65     tab = ' ' * (level * 4)
66     print >> fp, tab + msg.get_content_type(),
67     if include_default:
68         print >> fp, '[%s]' % msg.get_default_type()
69     else:
70         print >> fp
71     if msg.is_multipart():
72         for subpart in msg.get_payload():
73             _structure(subpart, fp, level+1, include_default)