zulip/zerver/management/commands/email-mirror.py

323 lines
11 KiB
Python
Executable File

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