295 lines
11 KiB
Python
295 lines
11 KiB
Python
import logging
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from re import match
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import aiosmtplib
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from channels.layers import get_channel_layer
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from channels.db import database_sync_to_async
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from django.core.files.base import ContentFile
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from mail.models import Email, EventAddress, EmailAttachment
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from notify_sessions.models import SystemEvent
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from tickets.models import IssueThread
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class SpecialMailException(Exception):
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pass
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def find_quoted_printable(s, marker):
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positions = [i for i in range(len(s)) if s.lower().startswith('=?utf-8?' + marker + '?', i)]
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for pos in positions:
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end = s.find('?=', pos + 10)
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if end == -1:
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continue
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yield pos, end + 3
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def unescape_and_decode_quoted_printable(s):
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import quopri
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decoded = ''
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last_end = 0
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for start, end in find_quoted_printable(s, 'q'):
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decoded += s[last_end:start]
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decoded += quopri.decodestring(s[start + 10:end - 3]).decode('utf-8')
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last_end = end
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decoded += s[last_end:]
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return decoded
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def unescape_and_decode_base64(s):
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import base64
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decoded = ''
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last_end = 0
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for start, end in find_quoted_printable(s, 'b'):
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decoded += s[last_end:start]
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decoded += base64.b64decode(s[start + 10:end - 3]).decode('utf-8')
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last_end = end
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decoded += s[last_end:]
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return decoded
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def unescape_simplified_quoted_printable(s):
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import quopri
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return quopri.decodestring(s).decode('utf-8')
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def collect_references(issue_thread):
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mails = issue_thread.emails.order_by('timestamp')
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references = []
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for mail in mails:
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if mail.reference:
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references.append(mail.reference)
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return references
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def make_reply(reply_email, references=None, event=None):
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from email.message import EmailMessage
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from core.settings import MAIL_DOMAIN
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event = event or "mail"
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reply = EmailMessage()
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reply["From"] = reply_email.sender
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reply["To"] = reply_email.recipient
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reply["Subject"] = reply_email.subject
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reply["Reply-To"] = f"{event}@{MAIL_DOMAIN}"
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if reply_email.in_reply_to:
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reply["In-Reply-To"] = reply_email.in_reply_to
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if reply_email.reference:
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reply["Message-ID"] = reply_email.reference
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else:
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reply["Message-ID"] = reply_email.id + "@" + MAIL_DOMAIN
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reply_email.reference = reply["Message-ID"]
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reply_email.save()
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if references:
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reply["References"] = " ".join(references)
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reply.set_content(reply_email.body)
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return reply
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async def send_smtp(message):
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await aiosmtplib.send(message, hostname="127.0.0.1", port=25, use_tls=False, start_tls=False)
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def find_active_issue_thread(in_reply_to, address, subject, event):
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from re import match
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uuid_match = match(r'^ticket\+([a-f0-9-]{36})@', address)
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if uuid_match:
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issue = IssueThread.objects.filter(uuid=uuid_match.group(1))
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if issue.exists():
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return issue.first(), False
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reply_to = Email.objects.filter(reference=in_reply_to)
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if reply_to.exists():
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return reply_to.first().issue_thread, False
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else:
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issue = IssueThread.objects.create(name=subject, event=event)
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return issue, True
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def find_target_event(address):
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try:
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address_map = EventAddress.objects.get(address=address)
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if address_map.event:
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return address_map.event
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except EventAddress.DoesNotExist:
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pass
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return None
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def parse_email_body(raw, log=None):
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import email
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from hashlib import sha256
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attachments = []
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parsed = email.message_from_bytes(raw)
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body = ""
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if parsed.is_multipart():
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for part in parsed.walk():
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ctype = part.get_content_type()
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cdispo = str(part.get('Content-Disposition'))
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# skip any text/plain (txt) attachments
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if ctype == 'text/plain' and 'attachment' not in cdispo:
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segment = part.get_payload()
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if not segment:
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continue
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segment = unescape_and_decode_quoted_printable(segment)
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segment = unescape_and_decode_base64(segment)
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if part.get('Content-Transfer-Encoding') == 'quoted-printable':
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segment = unescape_simplified_quoted_printable(segment)
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log.debug(segment)
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body = body + segment
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elif 'attachment' in cdispo or 'inline' in cdispo:
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file = ContentFile(part.get_payload(decode=True))
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chash = sha256(file.read()).hexdigest()
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name = part.get_filename()
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if name is None:
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name = "unnamed"
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attachment, _ = EmailAttachment.objects.get_or_create(
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name=name, mime_type=ctype, file=file, hash=chash)
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attachment.save()
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attachments.append(attachment)
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if 'inline' in cdispo:
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body = body + f'<img src="cid:{attachment.id}">'
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log.info("Image %s %s", ctype, attachment.id)
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else:
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log.info("Attachment %s %s", ctype, cdispo)
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else:
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if parsed.get_content_type() == 'text/plain':
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body = parsed.get_payload()
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elif parsed.get_content_type() == 'text/html':
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from bs4 import BeautifulSoup
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import re
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body = parsed.get_payload()
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soup = BeautifulSoup(body, 'html.parser')
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body = re.sub(r'([\r\n]+.?)*[\r\n]', r'\n', soup.get_text()).strip('\n')
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else:
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log.warning("Unknown content type %s", parsed.get_content_type())
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body = "Unknown content type"
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body = unescape_and_decode_quoted_printable(body)
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body = unescape_and_decode_base64(body)
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if parsed.get('Content-Transfer-Encoding') == 'quoted-printable':
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body = unescape_simplified_quoted_printable(body)
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log.debug(body)
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return parsed, body, attachments
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@database_sync_to_async
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def receive_email(envelope, log=None):
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parsed, body, attachments = parse_email_body(envelope.content, log)
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header_from = parsed.get('From')
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header_to = parsed.get('To')
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header_in_reply_to = parsed.get('In-Reply-To')
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header_message_id = parsed.get('Message-ID')
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if match(r'^([a-zA-Z ]*<)?MAILER-DAEMON@', header_from) and envelope.mail_from.strip("<>") == "":
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log.warning("Ignoring mailer daemon")
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raise SpecialMailException("Ignoring mailer daemon")
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if Email.objects.filter(reference=header_message_id).exists(): # break before issue thread is created
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log.warning("Email already exists")
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raise Exception("Email already exists")
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recipient = envelope.rcpt_tos[0].lower() if envelope.rcpt_tos else header_to.lower()
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sender = envelope.mail_from if envelope.mail_from else header_from
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subject = parsed.get('Subject')
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if not subject:
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subject = "No subject"
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subject = unescape_and_decode_quoted_printable(subject)
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subject = unescape_and_decode_base64(subject)
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target_event = find_target_event(recipient)
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active_issue_thread, new = find_active_issue_thread(header_in_reply_to, recipient, subject, target_event)
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from hashlib import sha256
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random_filename = 'mail-' + sha256(envelope.content).hexdigest()
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email = Email.objects.create(
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sender=sender, recipient=recipient, body=body, subject=subject, reference=header_message_id,
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in_reply_to=header_in_reply_to, raw_file=ContentFile(envelope.content, name=random_filename), event=target_event,
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issue_thread=active_issue_thread)
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for attachment in attachments:
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email.attachments.add(attachment)
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email.save()
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reply = None
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if new:
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# auto reply if new issue
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references = collect_references(active_issue_thread)
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if not sender.startswith('noreply'):
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subject = f"Re: {subject} [#{active_issue_thread.short_uuid()}]"
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body = '''Your request (#{}) has been received and will be reviewed by our lost&found angels.
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We are reviewing incoming requests during the event and teardown. Immediately after the event, expect a delay as the \
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workload is high. We will not forget about your request and get back in touch once we have updated information on your \
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request. Requests for devices, wallets, credit cards or similar items will be handled with priority.
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If you happen to find your lost item or just want to add additional information, please reply to this email. Please \
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do not create a new request.
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Your c3lf (Cloakroom + Lost&Found) Team'''.format(active_issue_thread.short_uuid())
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reply_email = Email.objects.create(
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sender=recipient, recipient=sender, body=body, subject=subject,
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in_reply_to=header_message_id, event=target_event, issue_thread=active_issue_thread)
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reply = make_reply(reply_email, references, event=target_event.slug if target_event else None)
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else:
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# change state if not new
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if active_issue_thread.state != 'pending_new':
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active_issue_thread.state = 'pending_open'
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active_issue_thread.save()
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return email, new, reply, active_issue_thread
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class LMTPHandler:
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async def handle_RCPT(self, server, session, envelope, address, rcpt_options):
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from core.settings import MAIL_DOMAIN
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address = address.lower()
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if not address.endswith('@' + MAIL_DOMAIN):
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return '550 not relaying to that domain'
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envelope.rcpt_tos.append(address)
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return '250 OK'
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async def handle_DATA(self, server, session, envelope):
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log = logging.getLogger('mail.log')
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log.setLevel(logging.DEBUG)
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log.info('Message from %s' % envelope.mail_from)
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log.info('Message for %s' % envelope.rcpt_tos)
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log.info('Message data:\n')
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content = None
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try:
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content = envelope.content
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email, new, reply, thread = await receive_email(envelope, log)
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log.info(f"Created email {email.id}")
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systemevent = await database_sync_to_async(SystemEvent.objects.create)(type='email received',
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reference=email.id)
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log.info(f"Created system event {systemevent.id}")
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channel_layer = get_channel_layer()
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await channel_layer.group_send(
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'general', {"type": "generic.event", "name": "send_message_to_frontend", "event_id": systemevent.id,
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"message": "email received"})
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log.info(f"Sent message to frontend")
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if new and reply:
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log.info('Sending message to %s' % reply['To'])
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await send_smtp(reply)
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log.info("Sent auto reply")
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return '250 Message accepted for delivery'
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except SpecialMailException as e:
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import uuid
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random_filename = 'special-' + str(uuid.uuid4())
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with open(random_filename, 'wb') as f:
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f.write(content)
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log.warning(f"Special mail exception: {e} saved to {random_filename}")
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return '250 Message accepted for delivery'
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except Exception as e:
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from hashlib import sha256
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random_filename = 'mail-' + sha256(content).hexdigest()
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with open(random_filename, 'wb') as f:
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f.write(content)
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log.error(f"Saved email to {random_filename} because of error %s (%s)", e, type(e))
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return '451 Internal server error'
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