mirror of https://github.com/zulip/zulip.git
432 lines
17 KiB
Python
432 lines
17 KiB
Python
from typing import Any, Dict, Optional, Tuple, List
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import logging
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import re
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from email.header import decode_header, make_header
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from email.utils import getaddresses
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import email.message as message
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from django.conf import settings
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from zerver.lib.actions import internal_send_message, internal_send_private_message, \
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internal_send_stream_message, internal_send_huddle_message, \
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truncate_body, truncate_topic
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from zerver.lib.email_mirror_helpers import decode_email_address, \
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get_email_gateway_message_string_from_address, ZulipEmailForwardError
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from zerver.lib.email_notifications import convert_html_to_markdown
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from zerver.lib.queue import queue_json_publish
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from zerver.lib.redis_utils import get_redis_client
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from zerver.lib.upload import upload_message_file
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from zerver.lib.utils import generate_random_token, statsd
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from zerver.lib.send_email import FromAddress
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from zerver.lib.rate_limiter import RateLimitedObject, RateLimiterLockingException, \
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is_ratelimited, incr_ratelimit
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from zerver.lib.exceptions import RateLimited
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from zerver.models import Stream, Recipient, \
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get_user_profile_by_id, get_display_recipient, get_personal_recipient, \
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Message, Realm, UserProfile, get_system_bot, get_user, get_stream_by_id_in_realm
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logger = logging.getLogger(__name__)
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def redact_stream(error_message: str) -> str:
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domain = settings.EMAIL_GATEWAY_PATTERN.rsplit('@')[-1]
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stream_match = re.search('\\b(.*?)@' + domain, error_message)
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if stream_match:
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stream_name = stream_match.groups()[0]
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return error_message.replace(stream_name, "X" * len(stream_name))
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return error_message
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def report_to_zulip(error_message: str) -> None:
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if settings.ERROR_BOT is None:
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return
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error_bot = get_system_bot(settings.ERROR_BOT)
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error_stream = Stream.objects.get(name="errors", realm=error_bot.realm)
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send_zulip(settings.ERROR_BOT, error_stream, "email mirror error",
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"""~~~\n%s\n~~~""" % (error_message,))
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def log_and_report(email_message: message.Message, error_message: str, debug_info: Dict[str, Any]) -> None:
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scrubbed_error = u"Sender: %s\n%s" % (email_message.get("From"),
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redact_stream(error_message))
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if "to" in debug_info:
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scrubbed_error = "Stream: %s\n%s" % (redact_stream(debug_info["to"]),
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scrubbed_error)
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if "stream" in debug_info:
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scrubbed_error = "Realm: %s\n%s" % (debug_info["stream"].realm.string_id,
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scrubbed_error)
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logger.error(scrubbed_error)
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report_to_zulip(scrubbed_error)
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# Temporary missed message addresses
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redis_client = get_redis_client()
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def missed_message_redis_key(token: str) -> str:
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return 'missed_message:' + token
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def is_missed_message_address(address: str) -> bool:
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try:
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msg_string = get_email_gateway_message_string_from_address(address)
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except ZulipEmailForwardError:
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return False
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return is_mm_32_format(msg_string)
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def is_mm_32_format(msg_string: Optional[str]) -> bool:
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'''
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Missed message strings are formatted with a little "mm" prefix
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followed by a randomly generated 32-character string.
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'''
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return msg_string is not None and msg_string.startswith('mm') and len(msg_string) == 34
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def get_missed_message_token_from_address(address: str) -> str:
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msg_string = get_email_gateway_message_string_from_address(address)
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if not is_mm_32_format(msg_string):
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raise ZulipEmailForwardError('Could not parse missed message address')
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# strip off the 'mm' before returning the redis key
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return msg_string[2:]
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def create_missed_message_address(user_profile: UserProfile, message: Message) -> str:
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if settings.EMAIL_GATEWAY_PATTERN == '':
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logger.warning("EMAIL_GATEWAY_PATTERN is an empty string, using "
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"NOREPLY_EMAIL_ADDRESS in the 'from' field.")
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return FromAddress.NOREPLY
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if message.recipient.type == Recipient.PERSONAL:
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# We need to reply to the sender so look up their personal recipient_id
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recipient_id = get_personal_recipient(message.sender_id).id
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else:
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recipient_id = message.recipient_id
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data = {
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'user_profile_id': user_profile.id,
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'recipient_id': recipient_id,
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'subject': message.topic_name().encode('utf-8'),
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}
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while True:
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token = generate_random_token(32)
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key = missed_message_redis_key(token)
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if redis_client.hsetnx(key, 'uses_left', 1):
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break
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with redis_client.pipeline() as pipeline:
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pipeline.hmset(key, data)
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pipeline.expire(key, 60 * 60 * 24 * 5)
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pipeline.execute()
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address = 'mm' + token
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return settings.EMAIL_GATEWAY_PATTERN % (address,)
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def mark_missed_message_address_as_used(address: str) -> None:
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token = get_missed_message_token_from_address(address)
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key = missed_message_redis_key(token)
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with redis_client.pipeline() as pipeline:
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pipeline.hincrby(key, 'uses_left', -1)
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pipeline.expire(key, 60 * 60 * 24 * 5)
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new_value = pipeline.execute()[0]
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if new_value < 0:
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redis_client.delete(key)
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raise ZulipEmailForwardError('Missed message address has already been used')
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def construct_zulip_body(message: message.Message, realm: Realm, show_sender: bool=False,
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remove_quotations: bool=True) -> str:
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body = extract_body(message, remove_quotations)
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# Remove null characters, since Zulip will reject
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body = body.replace("\x00", "")
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body = filter_footer(body)
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body += extract_and_upload_attachments(message, realm)
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body = body.strip()
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if not body:
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body = '(No email body)'
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if show_sender:
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sender = message.get("From")
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body = "From: %s\n%s" % (sender, body)
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return body
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def send_to_missed_message_address(address: str, message: message.Message) -> None:
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token = get_missed_message_token_from_address(address)
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key = missed_message_redis_key(token)
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result = redis_client.hmget(key, 'user_profile_id', 'recipient_id', 'subject')
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if not all(val is not None for val in result):
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raise ZulipEmailForwardError('Missing missed message address data')
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user_profile_id, recipient_id, subject_b = result # type: (bytes, bytes, bytes)
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user_profile = get_user_profile_by_id(user_profile_id)
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recipient = Recipient.objects.get(id=recipient_id)
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body = construct_zulip_body(message, user_profile.realm)
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if recipient.type == Recipient.STREAM:
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stream = get_stream_by_id_in_realm(recipient.type_id, user_profile.realm)
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internal_send_stream_message(
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user_profile.realm, user_profile, stream,
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subject_b.decode('utf-8'), body
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)
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recipient_str = stream.name
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elif recipient.type == Recipient.PERSONAL:
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display_recipient = get_display_recipient(recipient)
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assert not isinstance(display_recipient, str)
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recipient_str = display_recipient[0]['email']
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recipient_user = get_user(recipient_str, user_profile.realm)
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internal_send_private_message(user_profile.realm, user_profile,
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recipient_user, body)
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elif recipient.type == Recipient.HUDDLE:
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display_recipient = get_display_recipient(recipient)
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assert not isinstance(display_recipient, str)
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emails = [user_dict['email'] for user_dict in display_recipient]
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recipient_str = ', '.join(emails)
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internal_send_huddle_message(user_profile.realm, user_profile,
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emails, body)
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else:
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raise AssertionError("Invalid recipient type!")
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logger.info("Successfully processed email from %s to %s" % (
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user_profile.email, recipient_str))
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## Sending the Zulip ##
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class ZulipEmailForwardUserError(ZulipEmailForwardError):
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pass
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def send_zulip(sender: str, stream: Stream, topic: str, content: str) -> None:
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internal_send_message(
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stream.realm,
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sender,
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"stream",
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stream.name,
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truncate_topic(topic),
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truncate_body(content),
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email_gateway=True)
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def get_message_part_by_type(message: message.Message, content_type: str) -> Optional[str]:
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charsets = message.get_charsets()
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for idx, part in enumerate(message.walk()):
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if part.get_content_type() == content_type:
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content = part.get_payload(decode=True)
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assert isinstance(content, bytes)
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if charsets[idx]:
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return content.decode(charsets[idx], errors="ignore")
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return None
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talon_initialized = False
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def extract_body(message: message.Message, remove_quotations: bool=True) -> str:
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import talon
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global talon_initialized
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if not talon_initialized:
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talon.init()
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talon_initialized = True
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# If the message contains a plaintext version of the body, use
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# that.
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plaintext_content = get_message_part_by_type(message, "text/plain")
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if plaintext_content:
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if remove_quotations:
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return talon.quotations.extract_from_plain(plaintext_content)
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else:
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return plaintext_content
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# If we only have an HTML version, try to make that look nice.
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html_content = get_message_part_by_type(message, "text/html")
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if html_content:
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if remove_quotations:
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return convert_html_to_markdown(talon.quotations.extract_from_html(html_content))
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else:
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return convert_html_to_markdown(html_content)
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if plaintext_content is not None or html_content is not None:
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raise ZulipEmailForwardUserError("Email has no nonempty body sections; ignoring.")
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logging.warning("Content types: %s" % ([part.get_content_type() for part in message.walk()],))
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raise ZulipEmailForwardUserError("Unable to find plaintext or HTML message body")
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def filter_footer(text: str) -> str:
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# Try to filter out obvious footers.
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possible_footers = [line for line in text.split("\n") if line.strip() == "--"]
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if len(possible_footers) != 1:
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# Be conservative and don't try to scrub content if there
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# isn't a trivial footer structure.
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return text
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return text.partition("--")[0].strip()
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def extract_and_upload_attachments(message: message.Message, realm: Realm) -> str:
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user_profile = get_system_bot(settings.EMAIL_GATEWAY_BOT)
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attachment_links = []
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payload = message.get_payload()
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if not isinstance(payload, list):
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# This is not a multipart message, so it can't contain attachments.
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return ""
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for part in payload:
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content_type = part.get_content_type()
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filename = part.get_filename()
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if filename:
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attachment = part.get_payload(decode=True)
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if isinstance(attachment, bytes):
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s3_url = upload_message_file(filename, len(attachment), content_type,
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attachment,
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user_profile,
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target_realm=realm)
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formatted_link = "[%s](%s)" % (filename, s3_url)
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attachment_links.append(formatted_link)
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else:
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logger.warning("Payload is not bytes (invalid attachment %s in message from %s)." %
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(filename, message.get("From")))
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return "\n".join(attachment_links)
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def extract_and_validate(email: str) -> Tuple[Stream, bool]:
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token, show_sender = decode_email_address(email)
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try:
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stream = Stream.objects.get(email_token=token)
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except Stream.DoesNotExist:
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raise ZulipEmailForwardError("Bad stream token from email recipient " + email)
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return stream, show_sender
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def find_emailgateway_recipient(message: message.Message) -> str:
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# We can't use Delivered-To; if there is a X-Gm-Original-To
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# it is more accurate, so try to find the most-accurate
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# recipient list in descending priority order
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recipient_headers = ["X-Gm-Original-To", "Delivered-To",
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"Resent-To", "Resent-CC", "To", "CC"]
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pattern_parts = [re.escape(part) for part in settings.EMAIL_GATEWAY_PATTERN.split('%s')]
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match_email_re = re.compile(".*?".join(pattern_parts))
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header_addresses = [str(addr)
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for recipient_header in recipient_headers
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for addr in message.get_all(recipient_header, [])]
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for addr_tuple in getaddresses(header_addresses):
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if match_email_re.match(addr_tuple[1]):
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return addr_tuple[1]
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raise ZulipEmailForwardError("Missing recipient in mirror email")
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def strip_from_subject(subject: str) -> str:
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# strips RE and FWD from the subject
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# from: https://stackoverflow.com/questions/9153629/regex-code-for-removing-fwd-re-etc-from-email-subject
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reg = r"([\[\(] *)?\b(RE|FWD?) *([-:;)\]][ :;\])-]*|$)|\]+ *$"
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stripped = re.sub(reg, "", subject, flags = re.IGNORECASE | re.MULTILINE)
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return stripped.strip()
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def is_forwarded(subject: str) -> bool:
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# regex taken from strip_from_subject, we use it to detect various forms
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# of FWD at the beginning of the subject.
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reg = r"([\[\(] *)?\b(FWD?) *([-:;)\]][ :;\])-]*|$)|\]+ *$"
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return bool(re.match(reg, subject, flags=re.IGNORECASE))
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def process_stream_message(to: str, message: message.Message,
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debug_info: Dict[str, Any]) -> None:
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subject_header = str(make_header(decode_header(message.get("Subject", ""))))
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subject = strip_from_subject(subject_header) or "(no topic)"
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stream, show_sender = extract_and_validate(to)
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# Don't remove quotations if message is forwarded:
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remove_quotations = not is_forwarded(subject_header)
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body = construct_zulip_body(message, stream.realm, show_sender, remove_quotations)
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debug_info["stream"] = stream
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send_zulip(settings.EMAIL_GATEWAY_BOT, stream, subject, body)
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logger.info("Successfully processed email to %s (%s)" % (
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stream.name, stream.realm.string_id))
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def process_missed_message(to: str, message: message.Message, pre_checked: bool) -> None:
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if not pre_checked:
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mark_missed_message_address_as_used(to)
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send_to_missed_message_address(to, message)
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def process_message(message: message.Message, rcpt_to: Optional[str]=None, pre_checked: bool=False) -> None:
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debug_info = {}
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try:
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if rcpt_to is not None:
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to = rcpt_to
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else:
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to = find_emailgateway_recipient(message)
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debug_info["to"] = to
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if is_missed_message_address(to):
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process_missed_message(to, message, pre_checked)
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else:
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process_stream_message(to, message, debug_info)
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except ZulipEmailForwardError as e:
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if isinstance(e, ZulipEmailForwardUserError):
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# TODO: notify sender of error, retry if appropriate.
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logging.warning(str(e))
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else:
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log_and_report(message, str(e), debug_info)
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def mirror_email_message(data: Dict[str, str]) -> Dict[str, str]:
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rcpt_to = data['recipient']
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if is_missed_message_address(rcpt_to):
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try:
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mark_missed_message_address_as_used(rcpt_to)
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except ZulipEmailForwardError:
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return {
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"status": "error",
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"msg": "5.1.1 Bad destination mailbox address: "
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"Bad or expired missed message address."
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}
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else:
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try:
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extract_and_validate(rcpt_to)
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except ZulipEmailForwardError:
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return {
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"status": "error",
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"msg": "5.1.1 Bad destination mailbox address: "
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"Please use the address specified in your Streams page."
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}
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queue_json_publish(
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"email_mirror",
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{
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"message": data['msg_text'],
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"rcpt_to": rcpt_to
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}
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)
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return {"status": "success"}
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# Email mirror rate limiter code:
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class RateLimitedRealmMirror(RateLimitedObject):
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def __init__(self, realm: Realm) -> None:
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self.realm = realm
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def key_fragment(self) -> str:
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return "emailmirror:{}:{}".format(type(self.realm), self.realm.id)
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def rules(self) -> List[Tuple[int, int]]:
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return settings.RATE_LIMITING_MIRROR_REALM_RULES
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def rate_limit_mirror_by_realm(recipient_realm: Realm) -> None:
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# Code based on the rate_limit_user function:
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entity = RateLimitedRealmMirror(recipient_realm)
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ratelimited, time = is_ratelimited(entity)
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if ratelimited:
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statsd.incr("ratelimiter.limited.%s.%s" % (type(recipient_realm),
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recipient_realm.id))
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raise RateLimited()
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try:
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incr_ratelimit(entity)
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except RateLimiterLockingException:
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logger.warning("Email mirror rate limiter: Deadlock trying to "
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"incr_ratelimit for realm %s" % (recipient_realm.name,))
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raise RateLimited()
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