mirror of https://github.com/zulip/zulip.git
325 lines
11 KiB
Python
Executable File
325 lines
11 KiB
Python
Executable File
#!/usr/bin/python
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"""
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Forward messages sent to the configured email gateway to Zulip.
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Messages to that address go to the Inbox of emailgateway@zulip.com.
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Messages meant for Zulip have a special recipient form of
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<stream name>+<regenerable stream token>@streams.zulip.com
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We extract and validate the target stream from information in the
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recipient address and retrieve, forward, and archive the message.
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Run this management command out of a cron job.
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"""
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from __future__ import absolute_import
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import email
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import os
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from email.header import decode_header
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import logging
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import re
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import sys
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from django.conf import settings
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from django.core.management.base import BaseCommand
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from zerver.lib.actions import decode_email_address
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from zerver.lib.upload import upload_message_image
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from zerver.models import Stream, get_user_profile_by_email, UserProfile
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from twisted.internet import protocol, reactor, ssl
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from twisted.mail import imap4
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import html2text
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sys.path.insert(0, os.path.join(os.path.dirname(__file__), "../../../api"))
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import zulip
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## Setup ##
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log_format = "%(asctime)s: %(message)s"
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logging.basicConfig(format=log_format)
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formatter = logging.Formatter(log_format)
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file_handler = logging.FileHandler(settings.EMAIL_LOG_PATH)
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file_handler.setFormatter(formatter)
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logger = logging.getLogger(__name__)
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logger.setLevel(logging.DEBUG)
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logger.addHandler(file_handler)
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email_gateway_user = None
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api_key = None
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try:
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email_gateway_user = get_user_profile_by_email(settings.EMAIL_GATEWAY_BOT)
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api_key = email_gateway_user.api_key
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except UserProfile.DoesNotExist:
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print "No configured %s user" % (settings.EMAIL_GATEWAY_BOT,)
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if settings.DEPLOYED:
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staging_api_client = zulip.Client(
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site="https://staging.zulip.com",
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email=settings.EMAIL_GATEWAY_BOT,
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api_key=api_key)
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api_client = zulip.Client(
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site=settings.EXTERNAL_HOST,
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email=settings.EMAIL_GATEWAY_BOT,
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api_key=api_key)
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else:
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api_client = staging_api_client = zulip.Client(
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site=settings.EXTERNAL_HOST,
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email=settings.EMAIL_GATEWAY_BOT,
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api_key=api_key)
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def redact_stream(error_message):
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domain = settings.EMAIL_GATEWAY_PATTERN.rsplit('@')[-1]
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stream_match = re.search(r'\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):
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error_stream = Stream.objects.get(name="errors", realm__domain=settings.ADMIN_DOMAIN)
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send_zulip(error_stream, "email mirror error",
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"""~~~\n%s\n~~~""" % (error_message,))
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def log_and_report(email_message, error_message, debug_info):
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scrubbed_error = "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.domain,
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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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## Sending the Zulip ##
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class ZulipEmailForwardError(Exception):
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pass
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def send_zulip(stream, topic, content):
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# TODO: restrictions on who can send? Consider: cross-realm
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# messages, private streams.
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if stream.realm.domain == 'zulip.com':
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client = staging_api_client
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else:
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client = api_client
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message_data = {
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"type": "stream",
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# TODO: handle rich formatting.
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"content": content[:2000],
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"subject": topic[:60],
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"to": stream.name,
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"domain": stream.realm.domain
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}
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response = client.send_message(message_data)
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if response["result"] != "success":
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raise ZulipEmailForwardError(response["msg"])
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def valid_stream(stream_name, token):
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try:
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stream = Stream.objects.get(email_token=token)
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return stream.name.lower() == stream_name.lower()
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except Stream.DoesNotExist:
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return False
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def get_message_part_by_type(message, content_type):
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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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if charsets[idx]:
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content = content.decode(charsets[idx], errors="ignore")
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return content
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def extract_body(message):
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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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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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converter = html2text.HTML2Text()
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converter.ignore_links = True
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converter.ignore_images = True
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return converter.handle(html_content)
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raise ZulipEmailForwardError("Unable to find plaintext or HTML message body")
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def filter_footer(text):
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# Try to filter out obvious footers.
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possible_footers = filter(lambda line: line.strip().startswith("--"),
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text.split("\n"))
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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):
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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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s3_url = upload_message_image(filename, content_type,
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part.get_payload(decode=True),
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email_gateway_user)
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formatted_link = "[%s](%s)" % (filename, s3_url)
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attachment_links.append(formatted_link)
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return "\n".join(attachment_links)
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def extract_and_validate(email):
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try:
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stream_name, token = decode_email_address(email)
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except TypeError:
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raise ZulipEmailForwardError("Malformed email recipient " + email)
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if not valid_stream(stream_name, token):
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raise ZulipEmailForwardError("Bad stream token from email recipient " + email)
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return Stream.objects.get(email_token=token)
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## IMAP callbacks ##
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def logout(result, proto):
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# Log out.
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return proto.logout()
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def delete(result, proto):
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# Close the connection, which also processes any flags that were
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# set on messages.
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return proto.close().addCallback(logout, proto)
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def find_emailgateway_recipient(message):
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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", "To"]
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recipients = []
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for recipient_header in recipient_headers:
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r = message.get_all(recipient_header, None)
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if r:
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recipients = r
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break
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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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for recipient_email in recipients:
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if match_email_re.match(recipient_email):
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return recipient_email
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raise ZulipEmailForwardError("Missing recipient in mirror email")
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def fetch(result, proto, mailboxes):
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if not result:
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return proto.logout()
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message_uids = result.keys()
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# Make sure we forward the messages in time-order.
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message_uids.sort()
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for uid in message_uids:
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message = email.message_from_string(result[uid]["RFC822"])
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subject = decode_header(message.get("Subject", "(no subject)"))[0][0]
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debug_info = {}
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try:
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body = filter_footer(extract_body(message))
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to = find_emailgateway_recipient(message)
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debug_info["to"] = to
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stream = extract_and_validate(to)
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debug_info["stream"] = stream
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body += extract_and_upload_attachments(message)
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if not body:
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# You can't send empty Zulips, so to avoid confusion over the
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# email forwarding failing, set a dummy message body.
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body = "(No email body)"
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send_zulip(stream, subject, body)
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except ZulipEmailForwardError, e:
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# TODO: notify sender of error, retry if appropriate.
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log_and_report(message, e.message, debug_info)
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# Delete the processed messages from the Inbox.
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message_set = ",".join([result[key]["UID"] for key in message_uids])
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d = proto.addFlags(message_set, ["\\Deleted"], uid=True, silent=False)
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d.addCallback(delete, proto)
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return d
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def examine_mailbox(result, proto, mailbox):
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# Fetch messages from a particular mailbox.
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return proto.fetchMessage("1:*", uid=True).addCallback(fetch, proto, mailbox)
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def select_mailbox(result, proto):
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# Select which mailbox we care about.
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mbox = filter(lambda x: settings.EMAIL_GATEWAY_IMAP_FOLDER in x[2], result)[0][2]
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return proto.select(mbox).addCallback(examine_mailbox, proto, result)
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def list_mailboxes(res, proto):
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# List all of the mailboxes for this account.
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return proto.list("","*").addCallback(select_mailbox, proto)
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def connected(proto):
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d = proto.login(settings.EMAIL_GATEWAY_LOGIN, settings.EMAIL_GATEWAY_PASSWORD)
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d.addCallback(list_mailboxes, proto)
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d.addErrback(login_failed)
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return d
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def login_failed(failure):
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return failure
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def done(_):
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reactor.callLater(0, reactor.stop)
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def main():
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imap_client = protocol.ClientCreator(reactor, imap4.IMAP4Client)
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d = imap_client.connectSSL(settings.EMAIL_GATEWAY_IMAP_SERVER, settings.EMAIL_GATEWAY_IMAP_PORT, ssl.ClientContextFactory())
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d.addCallbacks(connected, login_failed)
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d.addBoth(done)
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class Command(BaseCommand):
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help = """Forward emails sent to the configured email gateway to Zulip.
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Run this command out of a cron job.
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"""
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def handle(self, **options):
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if (not settings.EMAIL_GATEWAY_BOT or not settings.EMAIL_GATEWAY_LOGIN or
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not settings.EMAIL_GATEWAY_PASSWORD or not settings.EMAIL_GATEWAY_IMAP_SERVER or
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not settings.EMAIL_GATEWAY_IMAP_PORT or not settings.EMAIL_GATEWAY_IMAP_FOLDER or
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not email_gateway_user):
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print "Please configure the Email Mirror Gateway in your local_settings.py"
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exit(1)
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reactor.callLater(0, main)
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reactor.run()
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