zulip/zerver/lib/email_mirror_helpers.py

79 lines
2.9 KiB
Python

import re
from django.conf import settings
from django.utils.text import slugify
from zerver.models import Stream
from typing import Tuple
class ZulipEmailForwardError(Exception):
pass
def get_email_gateway_message_string_from_address(address: str) -> str:
pattern_parts = [re.escape(part) for part in settings.EMAIL_GATEWAY_PATTERN.split('%s')]
if settings.EMAIL_GATEWAY_EXTRA_PATTERN_HACK:
# Accept mails delivered to any Zulip server
pattern_parts[-1] = settings.EMAIL_GATEWAY_EXTRA_PATTERN_HACK
match_email_re = re.compile("(.*?)".join(pattern_parts))
match = match_email_re.match(address)
if not match:
raise ZulipEmailForwardError('Address not recognized by gateway.')
msg_string = match.group(1)
return msg_string
def encode_email_address(stream: Stream) -> str:
return encode_email_address_helper(stream.name, stream.email_token)
def encode_email_address_helper(name: str, email_token: str) -> str:
# Some deployments may not use the email gateway
if settings.EMAIL_GATEWAY_PATTERN == '':
return ''
# Given the fact that we have almost no restrictions on stream names and
# that what characters are allowed in e-mail addresses is complicated and
# dependent on context in the address, we opt for a simple scheme:
# 1. Replace all substrings of non-alphanumeric characters with a single hyphen.
# 2. Use Django's slugify to convert the resulting name to ascii.
# 3. If the resulting name is shorter than the name we got in step 1,
# it means some letters can't be reasonably turned to ascii and have to be dropped,
# which would mangle the name, so we just skip the name part of the address.
name = re.sub(r"\W+", '-', name)
slug_name = slugify(name)
encoded_name = slug_name if len(slug_name) == len(name) else ''
# If encoded_name ends up empty, we just skip this part of the address:
if encoded_name:
encoded_token = "%s+%s" % (encoded_name, email_token)
else:
encoded_token = email_token
return settings.EMAIL_GATEWAY_PATTERN % (encoded_token,)
def decode_email_address(email: str) -> Tuple[str, bool]:
# Perform the reverse of encode_email_address. Returns a tuple of
# (email_token, show_sender)
msg_string = get_email_gateway_message_string_from_address(email)
if msg_string.endswith(('+show-sender', '.show-sender')):
show_sender = True
msg_string = msg_string[:-12] # strip "+show-sender"
else:
show_sender = False
# Workaround for Google Groups and other programs that don't accept emails
# that have + signs in them (see Trac #2102)
splitting_char = '.' if '.' in msg_string else '+'
parts = msg_string.split(splitting_char)
# msg_string may have one or two parts:
# [stream_name, email_token] or just [email_token]
if len(parts) == 1:
token = parts[0]
else:
token = parts[1]
return token, show_sender