1 # Copyright (C) 2001-2006 Python Software Foundation 2 # Author: Barry Warsaw 3 # Contact: email-sig (at] 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 21 def _qencode(s): 22 enc = _encodestring(s, quotetabs=True) 23 # Must encode spaces, which quopri.encodestring() doesn't do 24 return enc.replace(' ', '=20') 25 26 27 def _bencode(s): 28 # We can't quite use base64.encodestring() since it tacks on a "courtesy 29 # newline". Blech! 30 if not s: 31 return s 32 hasnewline = (s[-1] == '\n') 33 value = base64.encodestring(s) 34 if not hasnewline and value[-1] == '\n': 35 return value[:-1] 36 return value 37 38 39 41 def encode_base64(msg): 42 """Encode the message's payload in Base64. 43 44 Also, add an appropriate Content-Transfer-Encoding header. 45 """ 46 orig = msg.get_payload() 47 encdata = _bencode(orig) 48 msg.set_payload(encdata) 49 msg['Content-Transfer-Encoding'] = 'base64' 50 51 52 54 def encode_quopri(msg): 55 """Encode the message's payload in quoted-printable. 56 57 Also, add an appropriate Content-Transfer-Encoding header. 58 """ 59 orig = msg.get_payload() 60 encdata = _qencode(orig) 61 msg.set_payload(encdata) 62 msg['Content-Transfer-Encoding'] = 'quoted-printable' 63 64 65 67 def encode_7or8bit(msg): 68 """Set the Content-Transfer-Encoding header to 7bit or 8bit.""" 69 orig = msg.get_payload() 70 if orig is None: 71 # There's no payload. For backwards compatibility we use 7bit 72 msg['Content-Transfer-Encoding'] = '7bit' 73 return 74 # We play a trick to make this go fast. If encoding to ASCII succeeds, we 75 # know the data must be 7bit, otherwise treat it as 8bit. 76 try: 77 orig.encode('ascii') 78 except UnicodeError: 79 msg['Content-Transfer-Encoding'] = '8bit' 80 else: 81 msg['Content-Transfer-Encoding'] = '7bit' 82 83 84 86 def encode_noop(msg): 87 """Do nothing.""" 88
