Files
MigrateEmails/migrate_emails.py

213 lines
7.0 KiB
Python

import imaplib
import argparse
import sys
import re
import time
import email
from email.policy import default
# Increase limit for large emails
imaplib._MAXLINE = 10000000
def parse_args():
parser = argparse.ArgumentParser(description="Migrate emails via IMAP with Deduplication.")
# Source Creds
parser.add_argument('--src-host', required=True, help="Source IMAP Hostname")
parser.add_argument('--src-user', required=True, help="Source Username")
parser.add_argument('--src-pass', required=True, help="Source Password")
# Dest Creds
parser.add_argument('--dst-host', required=True, help="Destination IMAP Hostname")
parser.add_argument('--dst-user', required=True, help="Destination Username")
parser.add_argument('--dst-pass', required=True, help="Destination Password")
parser.add_argument('--dry-run', action='store_true', help="Simulate actions without moving data")
parser.add_argument('--ssl', action='store_true', default=True, help="Use SSL (Default: True)")
return parser.parse_args()
def connect_imap(host, user, password, use_ssl=True):
try:
if use_ssl:
mail = imaplib.IMAP4_SSL(host)
else:
mail = imaplib.IMAP4(host)
mail.login(user, password)
return mail
except Exception as e:
print(f"Error connecting to {host}: {e}")
sys.exit(1)
def get_folder_list(mail):
status, folders = mail.list()
if status != 'OK':
print("Failed to retrieve folder list.")
return []
clean_folders = []
for folder in folders:
decoded = folder.decode('utf-8')
# Regex to extract folder name from standard IMAP response
parts = re.search(r' \".\" \"?(.+?)\"?$', decoded) or re.search(r' \S \S (.+)$', decoded)
if parts:
name = parts.group(1).replace('"', '')
clean_folders.append(name)
else:
clean_folders.append(decoded.split(' ')[-1].replace('"', ''))
return clean_folders
def get_destination_message_ids(dst, folder_name):
"""
Fetches only the Message-IDs from the destination folder
to build a set for deduplication.
"""
existing_ids = set()
# Select folder on destination
try:
status, _ = dst.select(f'"{folder_name}"', readonly=True)
if status != 'OK':
return existing_ids # Folder probably empty or doesn't exist yet
except:
return existing_ids
status, messages = dst.search(None, 'ALL')
msg_ids = messages[0].split()
if not msg_ids:
return existing_ids
print(f" -> Indexing {len(msg_ids)} existing emails on destination for deduplication...")
# Fetch headers in batches would be faster, but simple iteration is safer for compatibility
# We fetch ONLY the header fields to save bandwidth
for num in msg_ids:
try:
# PEEK prevents marking read, though usually not critical on destination
typ, data = dst.fetch(num, '(BODY.PEEK[HEADER.FIELDS (MESSAGE-ID)])')
if typ == 'OK':
header_data = data[0][1]
# Parse the byte string into an email object to extract ID reliably
msg = email.message_from_bytes(header_data, policy=default)
msg_id = msg.get("Message-ID")
if msg_id:
existing_ids.add(msg_id.strip())
except Exception:
continue
return existing_ids
def migrate_folder(src, dst, folder_name, dry_run):
print(f"\n--- Processing: {folder_name} ---")
# 1. Prepare Destination (Create & Index)
existing_ids = set()
if not dry_run:
try:
dst.create(f'"{folder_name}"')
except imaplib.IMAP4.error:
pass
# Build dedupe index
existing_ids = get_destination_message_ids(dst, folder_name)
# 2. Select Source
status, _ = src.select(f'"{folder_name}"', readonly=True)
if status != 'OK':
print(f"Skipping {folder_name}: Could not select on source.")
return
# 3. Get Source Messages
status, messages = src.search(None, 'ALL')
msg_ids = messages[0].split()
total = len(msg_ids)
print(f"Found {total} emails in source '{folder_name}'.")
moved_count = 0
skipped_count = 0
for msg_id in msg_ids:
# Fetch Flags, Date, and Body
res, msg_data = src.fetch(msg_id, '(FLAGS INTERNALDATE BODY.PEEK[])')
if res != 'OK':
print(f"X", end="", flush=True)
continue
raw_email = None
flags = None
date_str = None
for part in msg_data:
if isinstance(part, tuple):
flags_match = re.search(r'FLAGS \((.*?)\)', part[0].decode('utf-8'))
if flags_match:
flags = flags_match.group(1)
date_match = re.search(r'INTERNALDATE \"(.*?)\"', part[0].decode('utf-8'))
if date_match:
date_str = date_match.group(1)
raw_email = part[1]
if raw_email:
# Check Deduplication
msg_obj = email.message_from_bytes(raw_email, policy=default)
src_msg_id = msg_obj.get("Message-ID")
if src_msg_id and src_msg_id.strip() in existing_ids:
# Duplicate found
print("S", end="", flush=True) # S for Skipped
skipped_count += 1
continue
# Not a duplicate, proceed to append
if dry_run:
print(".", end="", flush=True)
moved_count += 1
else:
delivery_time = imaplib.Time2Internaldate(time.localtime())
if date_str:
delivery_time = f'"{date_str}"'
flag_str = f'({flags})' if flags else None
try:
dst.append(f'"{folder_name}"', flag_str, delivery_time, raw_email)
print(".", end="", flush=True)
moved_count += 1
# Update local index so we don't duplicate if source has duplicates
if src_msg_id:
existing_ids.add(src_msg_id.strip())
except Exception as e:
print(f"E", end="", flush=True) # E for Error
print(f"\nResult: {moved_count} moved, {skipped_count} skipped (duplicates).")
def main():
args = parse_args()
print("Connecting to Source...")
src = connect_imap(args.src_host, args.src_user, args.src_pass, args.ssl)
print("Connecting to Destination...")
dst = connect_imap(args.dst_host, args.dst_user, args.dst_pass, args.ssl)
print("Fetching folder list...")
folders = get_folder_list(src)
print(f"Detected folders: {folders}")
if args.dry_run:
print("\n*** DRY RUN MODE ***")
for folder in folders:
migrate_folder(src, dst, folder, args.dry_run)
print("\n\nMigration Complete.")
src.logout()
dst.logout()
if __name__ == "__main__":
main()