AppPkg/Applications/Python/Python-2.7.2/Lib/email/encoders.py

   1 # Copyright (C) 2001-2006 Python Software Foundation
   2 # Author: Barry Warsaw
   3 # Contact: email-sig@python.org
   4
   5 """Encodings and related functions."""
   6
   7 __all__ = [
   8     'encode_7or8bit',
   9     'encode_base64',
  10     'encode_noop',
  11     'encode_quopri',
  12     ]
  13
  14 import base64
  15
  16 from quopri import encodestring as _encodestring
  17
  18
  19 \f
  20 def _qencode(s):
  21     enc = _encodestring(s, quotetabs=True)
  22     # Must encode spaces, which quopri.encodestring() doesn't do
  23     return enc.replace(' ', '=20')
  24
  25
  26 def _bencode(s):
  27     # We can't quite use base64.encodestring() since it tacks on a "courtesy
  28     # newline".  Blech!
  29     if not s:
  30         return s
  31     hasnewline = (s[-1] == '\n')
  32     value = base64.encodestring(s)
  33     if not hasnewline and value[-1] == '\n':
  34         return value[:-1]
  35     return value
  36
  37
  38 \f
  39 def encode_base64(msg):
  40     """Encode the message's payload in Base64.
  41
  42     Also, add an appropriate Content-Transfer-Encoding header.
  43     """
  44     orig = msg.get_payload()
  45     encdata = _bencode(orig)
  46     msg.set_payload(encdata)
  47     msg['Content-Transfer-Encoding'] = 'base64'
  48
  49
  50 \f
  51 def encode_quopri(msg):
  52     """Encode the message's payload in quoted-printable.
  53
  54     Also, add an appropriate Content-Transfer-Encoding header.
  55     """
  56     orig = msg.get_payload()
  57     encdata = _qencode(orig)
  58     msg.set_payload(encdata)
  59     msg['Content-Transfer-Encoding'] = 'quoted-printable'
  60
  61
  62 \f
  63 def encode_7or8bit(msg):
  64     """Set the Content-Transfer-Encoding header to 7bit or 8bit."""
  65     orig = msg.get_payload()
  66     if orig is None:
  67         # There's no payload.  For backwards compatibility we use 7bit
  68         msg['Content-Transfer-Encoding'] = '7bit'
  69         return
  70     # We play a trick to make this go fast.  If encoding to ASCII succeeds, we
  71     # know the data must be 7bit, otherwise treat it as 8bit.
  72     try:
  73         orig.encode('ascii')
  74     except UnicodeError:
  75         msg['Content-Transfer-Encoding'] = '8bit'
  76     else:
  77         msg['Content-Transfer-Encoding'] = '7bit'
  78
  79
  80 \f
  81 def encode_noop(msg):
  82     """Do nothing."""