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# Copyright (C) 2001-2006 Python Software Foundation
# Author: Barry Warsaw
# Contact: email-sig@python.org
"""Encodings and related functions."""
__all__ = [
'encode_7or8bit',
'encode_base64',
'encode_noop',
'encode_quopri',
]
from base64 import encodebytes as _bencode
from quopri import encodestring as _encodestring
def _qencode(s):
enc = _encodestring(s, quotetabs=True)
# Must encode spaces, which quopri.encodestring() doesn't do
return enc.replace(b' ', b'=20')
def encode_base64(msg):
"""Encode the message's payload in Base64.
Also, add an appropriate Content-Transfer-Encoding header.
"""
orig = msg.get_payload()
encdata = str(_bencode(orig), 'ascii')
msg.set_payload(encdata)
msg['Content-Transfer-Encoding'] = 'base64'
def encode_quopri(msg):
"""Encode the message's payload in quoted-printable.
Also, add an appropriate Content-Transfer-Encoding header.
"""
orig = msg.get_payload()
if isinstance(orig, str):
# If it is a string, the model data may have binary data encoded in via
# surrogateescape. Convert back to bytes so we can CTE encode it.
orig = orig.encode('ascii', 'surrogateescape')
encdata = _qencode(orig)
msg.set_payload(encdata.decode('ascii', 'surrogateescape'))
msg['Content-Transfer-Encoding'] = 'quoted-printable'
def encode_7or8bit(msg):
"""Set the Content-Transfer-Encoding header to 7bit or 8bit."""
orig = msg.get_payload()
if orig is None:
# There's no payload. For backwards compatibility we use 7bit
msg['Content-Transfer-Encoding'] = '7bit'
return
# We play a trick to make this go fast. If encoding/decode to ASCII
# succeeds, we know the data must be 7bit, otherwise treat it as 8bit.
try:
if isinstance(orig, str):
orig.encode('ascii')
else:
orig.decode('ascii')
except UnicodeError:
charset = msg.get_charset()
output_cset = charset and charset.output_charset
# iso-2022-* is non-ASCII but encodes to a 7-bit representation
if output_cset and output_cset.lower().startswith('iso-2022-'):
msg['Content-Transfer-Encoding'] = '7bit'
else:
msg['Content-Transfer-Encoding'] = '8bit'
else:
msg['Content-Transfer-Encoding'] = '7bit'
if not isinstance(orig, str):
msg.set_payload(orig.decode('ascii', 'surrogateescape'))
def encode_noop(msg):
"""Do nothing."""
# Well, not quite *nothing*: in Python3 we have to turn bytes into a string
# in our internal surrogateescaped form in order to keep the model
# consistent.
orig = msg.get_payload()
if not isinstance(orig, str):
msg.set_payload(orig.decode('ascii', 'surrogateescape'))
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