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