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      1 # Copyright (C) 2001-2006 Python Software Foundation
      2 # Author: Barry Warsaw
      3 # Contact: email-sig (at] 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 
     20 # This function will become a method of the Message class
     21 def walk(self):
     22     """Walk over the message tree, yielding each subpart.
     23 
     24     The walk is performed in depth-first order.  This method is a
     25     generator.
     26     """
     27     yield self
     28     if self.is_multipart():
     29         for subpart in self.get_payload():
     30             for subsubpart in subpart.walk():
     31                 yield subsubpart
     32 
     33 
     34 
     36 # These two functions are imported into the Iterators.py interface module.
     37 def body_line_iterator(msg, decode=False):
     38     """Iterate over the parts, returning string payloads line-by-line.
     39 
     40     Optional decode (default False) is passed through to .get_payload().
     41     """
     42     for subpart in msg.walk():
     43         payload = subpart.get_payload(decode=decode)
     44         if isinstance(payload, basestring):
     45             for line in StringIO(payload):
     46                 yield line
     47 
     48 
     49 def typed_subpart_iterator(msg, maintype='text', subtype=None):
     50     """Iterate over the subparts with a given MIME type.
     51 
     52     Use `maintype' as the main MIME type to match against; this defaults to
     53     "text".  Optional `subtype' is the MIME subtype to match against; if
     54     omitted, only the main type is matched.
     55     """
     56     for subpart in msg.walk():
     57         if subpart.get_content_maintype() == maintype:
     58             if subtype is None or subpart.get_content_subtype() == subtype:
     59                 yield subpart
     60 
     61 
     62 
     64 def _structure(msg, fp=None, level=0, include_default=False):
     65     """A handy debugging aid"""
     66     if fp is None:
     67         fp = sys.stdout
     68     tab = ' ' * (level * 4)
     69     print >> fp, tab + msg.get_content_type(),
     70     if include_default:
     71         print >> fp, '[%s]' % msg.get_default_type()
     72     else:
     73         print >> fp
     74     if msg.is_multipart():
     75         for subpart in msg.get_payload():
     76             _structure(subpart, fp, level+1, include_default)
     77