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 14import base64 15 16from quopri import encodestring as _encodestring 17 18 19 20def _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 26def _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 39def 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 51def 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 63def 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 81def encode_noop(msg): 82 """Do nothing.""" 83