Christian Krakau-Louis
4c95e6ec6c
Refactor IMAP Tasks: Filter Allowed Attachment Types & Improve Code Quality - Filter attachments to process only office files, PDFs, plain text, CSV, and RTF, explicitly skipping common image MIME types. - Use an explicit elif for clarity in attachment processing logic. - Remove dead code by not reassigning the result of fetch_attachments_and_enqueue. - Reformat log messages, docstrings, and break long lines to comply with PEP 8. - Add clarifying comments for excluded image MIME types.
413 lines
14 KiB
Python
413 lines
14 KiB
Python
#!/usr/bin/env python3
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import os
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import json
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import email
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import imaplib
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import logging
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import redis
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import re
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from datetime import datetime, timedelta, timezone
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from celery import shared_task
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from app.config import settings
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from app.tasks.upload_to_s3 import upload_to_s3
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from app.tasks.convert_to_pdf import convert_to_pdf # new conversion task
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logger = logging.getLogger(__name__)
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# Initialize Redis connection using Celery's Redis settings
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redis_client = redis.StrictRedis.from_url(settings.redis_url, decode_responses=True)
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LOCK_KEY = "imap_lock" # Unique key for locking
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LOCK_EXPIRE = 300 # Lock expires in 5 minutes
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# Local cache file for tracking processed emails
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CACHE_FILE = os.path.join(settings.workdir, "processed_mails.json")
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def acquire_lock():
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"""Attempt to acquire a Redis-based lock. If acquired, set an expiration."""
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lock_acquired = redis_client.setnx(LOCK_KEY, "locked")
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if lock_acquired:
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redis_client.expire(LOCK_KEY, LOCK_EXPIRE)
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logger.info("Lock acquired for IMAP processing.")
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return True
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logger.warning("Lock already held. Skipping this cycle.")
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return False
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def release_lock():
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"""Release the lock by deleting the Redis key."""
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redis_client.delete(LOCK_KEY)
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logger.info("Lock released.")
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def load_processed_emails():
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"""Load the list of already processed emails from a local JSON file."""
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if os.path.exists(CACHE_FILE):
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try:
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with open(CACHE_FILE, "r") as f:
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processed_emails = json.load(f)
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processed_emails = cleanup_old_entries(processed_emails)
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return processed_emails
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except json.JSONDecodeError:
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logger.warning("Failed to decode JSON, resetting processed emails cache.")
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return {}
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return {}
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def save_processed_emails(processed_emails):
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"""Save the processed email IDs to a local JSON file."""
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with open(CACHE_FILE, "w") as f:
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json.dump(processed_emails, f, indent=4)
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def cleanup_old_entries(processed_emails):
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"""Remove entries older than 7 days from the cache to avoid infinite growth."""
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seven_days_ago = datetime.now(timezone.utc) - timedelta(days=7)
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valid_emails = {}
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for msg_id, date_str in processed_emails.items():
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naive_dt = datetime.strptime(date_str, "%Y-%m-%dT%H:%M:%S")
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aware_dt = naive_dt.replace(tzinfo=timezone.utc)
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if aware_dt > seven_days_ago:
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valid_emails[msg_id] = date_str
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return valid_emails
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@shared_task
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def pull_all_inboxes():
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"""
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Periodic Celery task that checks all configured IMAP mailboxes
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and fetches attachments from new emails.
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Ensures only one instance runs at a time using Redis-based locking.
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"""
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if not acquire_lock():
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logger.info("Skipping execution: Another instance is running.")
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return
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try:
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logger.info("Starting pull_all_inboxes")
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# Mailbox #1 (non-Gmail)
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check_and_pull_mailbox(
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mailbox_key="imap1",
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host=settings.imap1_host,
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port=settings.imap1_port,
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username=settings.imap1_username,
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password=settings.imap1_password,
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use_ssl=settings.imap1_ssl,
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delete_after_process=settings.imap1_delete_after_process,
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)
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# Mailbox #2 (Gmail)
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check_and_pull_mailbox(
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mailbox_key="imap2",
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host=settings.imap2_host,
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port=settings.imap2_port,
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username=settings.imap2_username,
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password=settings.imap2_password,
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use_ssl=settings.imap2_ssl,
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delete_after_process=settings.imap2_delete_after_process,
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)
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logger.info("Finished pull_all_inboxes")
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finally:
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release_lock()
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def check_and_pull_mailbox(
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mailbox_key: str,
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host: str | None,
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port: int | None,
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username: str | None,
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password: str | None,
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use_ssl: bool,
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delete_after_process: bool,
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):
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"""Validates config and invokes pulling from the mailbox if valid."""
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if not (host and port and username and password):
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logger.warning(f"Mailbox {mailbox_key} is missing config, skipping.")
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return
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logger.info(f"Checking mailbox: {mailbox_key}")
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pull_inbox(
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mailbox_key=mailbox_key,
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host=host,
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port=port,
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username=username,
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password=password,
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use_ssl=use_ssl,
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delete_after_process=delete_after_process,
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)
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def pull_inbox(mailbox_key, host, port, username, password, use_ssl,
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delete_after_process):
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"""
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Connects to the IMAP inbox, fetches new unread emails from the last 3 days,
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and processes attachments while preserving the original unread status.
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For Gmail:
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- Attempts to select the localized All Mail folder.
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- Runs an X-GM-RAW query: "in:anywhere in:unread newer_than:3d has:attachment".
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For non-Gmail mailboxes, it falls back to selecting the INBOX with a SINCE/UNSEEN filter.
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"""
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logger.info("Connecting to %s at %s:%s (SSL=%s)",
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mailbox_key, host, port, use_ssl)
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processed_emails = load_processed_emails()
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try:
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mail = imaplib.IMAP4_SSL(host, port) if use_ssl else imaplib.IMAP4(host, port)
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mail.login(username, password)
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is_gmail_host = "gmail" in host.lower()
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if is_gmail_host:
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# For Gmail, try to select the localized All Mail folder.
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all_mail_folder = find_all_mail_folder(mail)
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if all_mail_folder:
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logger.info("Using Gmail All Mail folder: %s", all_mail_folder)
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mail.select(f'"{all_mail_folder}"')
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else:
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logger.warning("Gmail All Mail folder not found, falling back to INBOX.")
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mail.select("INBOX")
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# Use the X-GM-RAW query for Gmail.
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raw_query = "in:anywhere in:unread newer_than:3d has:attachment"
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status, search_data = mail.search(None, "X-GM-RAW", f'"{raw_query}"')
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else:
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# For non-Gmail, select INBOX and use SINCE/UNSEEN query.
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mail.select("INBOX")
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since_date = (datetime.now(timezone.utc) - timedelta(days=3)
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).strftime("%d-%b-%Y")
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status, search_data = mail.search(None, f'(SINCE {since_date} UNSEEN)')
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if status != "OK":
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logger.warning("Search failed on mailbox %s. Status=%s",
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mailbox_key, status)
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mail.close()
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mail.logout()
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return
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msg_numbers = search_data[0].split()
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logger.info("Found %d unread emails in %s.", len(msg_numbers), mailbox_key)
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for num in msg_numbers:
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status, msg_data = mail.fetch(num, "(RFC822)")
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if status != "OK":
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logger.warning("Failed to fetch message %s in %s. Status=%s",
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num, mailbox_key, status)
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continue
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raw_email = msg_data[0][1]
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email_message = email.message_from_bytes(raw_email)
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msg_id = email_message.get("Message-ID")
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if not msg_id:
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logger.warning("Skipping email without Message-ID in %s", mailbox_key)
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continue
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if msg_id in processed_emails:
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logger.info("Skipping already processed email %s in %s", msg_id, mailbox_key)
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continue
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# For Gmail, check if the email already has the "Ingested" label.
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if is_gmail_host:
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if email_already_has_label(mail, num, "Ingested"):
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logger.info("Skipping email %s in %s, already labeled 'Ingested'.",
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msg_id, mailbox_key)
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continue
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# Process attachments (and convert non-PDF files).
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# We call the function without assigning its return value since it is not used.
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fetch_attachments_and_enqueue(email_message)
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if is_gmail_host:
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mark_as_processed_with_star(mail, num)
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mark_as_processed_with_label(mail, num, label="Ingested")
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processed_emails[msg_id] = datetime.now(timezone.utc).strftime("%Y-%m-%dT%H:%M:%S")
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save_processed_emails(processed_emails)
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if delete_after_process:
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logger.info("Deleting message %s from %s", num.decode(), mailbox_key)
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mail.store(num, "+FLAGS", "\\Deleted")
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else:
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mail.store(num, "-FLAGS", "\\Seen")
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if delete_after_process:
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mail.expunge()
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mail.close()
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mail.logout()
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logger.info("Finished processing mailbox %s", mailbox_key)
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except Exception as e:
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logger.exception("Error pulling mailbox %s: %s", mailbox_key, e)
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def fetch_attachments_and_enqueue(email_message):
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"""
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Extracts attachments from the email and processes only allowed file types.
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Allowed file types include:
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- PDF: application/pdf
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- Microsoft Office files:
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- Word: application/msword,
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application/vnd.openxmlformats-officedocument.wordprocessingml.document
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- Excel: application/vnd.ms-excel,
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application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
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- PowerPoint: application/vnd.ms-powerpoint,
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application/vnd.openxmlformats-officedocument.presentationml.presentation
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- Other meaningful attachments:
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- Plain text: text/plain
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- CSV: text/csv
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- Rich Text Format: application/rtf, text/rtf
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Attachments not in this list are skipped. Common image MIME types such as
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image/jpeg, image/png, image/gif, image/bmp, image/tiff, and image/webp are
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intentionally excluded.
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If the attachment is a PDF, it is enqueued for upload; any other allowed file
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is enqueued for conversion to PDF.
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Returns True if at least one allowed attachment was processed.
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"""
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ALLOWED_MIME_TYPES = {
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"application/pdf",
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"application/msword",
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"application/vnd.openxmlformats-officedocument.wordprocessingml.document",
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"application/vnd.ms-excel",
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"application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
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"application/vnd.ms-powerpoint",
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"application/vnd.openxmlformats-officedocument.presentationml.presentation",
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"text/plain",
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"text/csv",
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"application/rtf",
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"text/rtf",
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}
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has_attachment = False
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for part in email_message.walk():
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if part.get_content_maintype() == "multipart":
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continue
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filename = part.get_filename()
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if not filename:
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continue
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mime_type = part.get_content_type()
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if mime_type not in ALLOWED_MIME_TYPES:
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logger.info("Skipping attachment %s with MIME type %s",
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filename, mime_type)
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continue
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file_path = os.path.join(settings.workdir, filename)
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with open(file_path, "wb") as f:
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f.write(part.get_payload(decode=True))
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if mime_type == "application/pdf":
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upload_to_s3.delay(file_path)
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logger.info("Enqueued PDF for upload: %s", filename)
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elif mime_type in ALLOWED_MIME_TYPES:
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# Enqueue conversion to PDF using the Gotenberg service.
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convert_to_pdf.delay(file_path)
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logger.info("Enqueued file for conversion to PDF: %s", filename)
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has_attachment = True
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return has_attachment
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def email_already_has_label(mail, msg_id, label="Ingested"):
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"""
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Checks if the given message (msg_id) has the specified Gmail label.
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Returns True if the label is found, False otherwise.
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"""
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try:
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label_status, label_data = mail.fetch(msg_id, "(X-GM-LABELS)")
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if label_status == "OK" and label_data and len(label_data) > 0:
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raw_labels = label_data[0][1].decode("utf-8", errors="ignore")
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if label in raw_labels:
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return True
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except Exception as e:
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logger.error("Failed to fetch labels for msg_id=%s: %s", msg_id, e)
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return False
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def mark_as_processed_with_star(mail, msg_id):
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"""Stars the email in Gmail."""
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try:
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mail.store(msg_id, "+FLAGS", "\\Flagged")
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logger.info("Email %s starred in Gmail.", msg_id)
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except Exception as e:
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logger.error("Failed to star email %s: %s", msg_id, e)
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def mark_as_processed_with_label(mail, msg_id, label="Ingested"):
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"""Adds a custom label to the email in Gmail."""
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try:
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mail.store(msg_id, "+X-GM-LABELS", label)
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logger.info("Email %s labeled '%s' in Gmail.", msg_id, label)
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except Exception as e:
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logger.error("Failed to label email %s with %s: %s", msg_id, label, e)
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def find_all_mail_folder(mail):
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"""
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Attempts to select the Gmail All Mail folder using known localized names.
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Falls back to using XLIST if needed.
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Returns the folder name if found, otherwise None.
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"""
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COMMON_ALL_MAIL_NAMES = [
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"[Gmail]/Alle Nachrichten",
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"[Gmail]/All Mail",
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"[Gmail]/Todos",
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"[Gmail]/Tutte le mail",
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"[Gmail]/Tous les messages",
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]
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for candidate in COMMON_ALL_MAIL_NAMES:
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status, _ = mail.select(f'"{candidate}"', readonly=True)
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if status == "OK":
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return candidate
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capabilities = get_capabilities(mail)
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if "XLIST" in capabilities:
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candidate = find_all_mail_xlist(mail)
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if candidate:
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return candidate
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return None
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def get_capabilities(mail):
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"""Returns a list of capabilities supported by the IMAP server."""
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typ, data = mail.capability()
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if typ == "OK" and data:
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caps = data[0].decode("utf-8", errors="ignore").upper().split()
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return caps
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return []
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def find_all_mail_xlist(mail):
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"""
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Uses XLIST to discover the mailbox flagged as All Mail.
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Returns the folder name if found, otherwise None.
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"""
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tag = mail._new_tag().decode("ascii")
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command_str = f"{tag} XLIST \"\" \"*\""
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mail.send((command_str + "\r\n").encode("utf-8"))
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all_mail_folder = None
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while True:
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line = mail.readline()
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if not line:
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break
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line_str = line.decode("utf-8", errors="ignore").strip()
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if line_str.upper().startswith("* XLIST ") and "\\ALLMAIL" in line_str.upper():
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match = re.search(r'"([^"]+)"$', line_str)
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if match:
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candidate = match.group(1)
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logger.info("Found All Mail folder via XLIST: %s", candidate)
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all_mail_folder = candidate
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if line_str.startswith(tag):
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break
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return all_mail_folder
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