micropython-lib/unix-ffi/email.encoders/email/encoders.py

75 wiersze
2.1 KiB
Python

# 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(decode=True)
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(decode=True)
encdata = _qencode(orig)
msg.set_payload(encdata)
msg["Content-Transfer-Encoding"] = "quoted-printable"
def encode_7or8bit(msg):
"""Set the Content-Transfer-Encoding header to 7bit or 8bit."""
orig = msg.get_payload(decode=True)
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"
def encode_noop(msg):
"""Do nothing."""