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