Script to delete large folder in gmail.

delete_large_gmail_folder.py

"""
Script to delete large folder in gmail.

Adapted from: http://ae.ro/1upv7rt

Notes:

1. For this to work with gmail, you will need to adjust into your IMAP settings
   so that they look like this:
    * IMAP: enabled
    * Auto-expunge: off
    * When a message is marked as deleted and expunged: immediately delete
2. If you have 2FA enabled, you will need to disable it to use this script, or
   you can use an application specific password.
3. For extremely large folders (1M+ messages), this will take a _long_ time.
   Run it overnight.
4. To handle occasional failure (network or otherwise), run in a retry loop,
   e.g.:

```
until python delete_large_gmail_folder.py <email> <password> <label>; do sleep 10; done
```
"""

import imaplib
import sys
imaplib._MAXLINE = 400000000

if len(sys.argv) != 4:
    print("Usage: python %s <email> <password> <label>" % sys.argv[0])
    sys.exit(1)

email    = sys.argv[1]
password = sys.argv[2]
label    = sys.argv[3]

CHUNK_SIZE = 250

def mail_connect():
    mail = imaplib.IMAP4_SSL("imap.gmail.com")
    mail.login(email, password)
    mail.select(label)
    return mail

def chunks(arr, num):
    for i in range(0, len(arr), num):
        yield arr[i:i + num]

print("Connecting...")
mail = mail_connect()

print("Acquiring message IDs...")
_, data = mail.search(None, "UNDELETED")
ids = data[0].split()
length = len(ids)

counter = 1
print("Messages to delete: " + str(length))
print("Deleting messages...")

for i in list(chunks(ids, CHUNK_SIZE)):

    # Add deleted flag and remove from inbox, i.e. delete irrevocably.
    mail.store(",".join(i), "-X-GM-LABELS", "\\Inbox")
    mail.store(",".join(i), "+X-GM-LABELS", "\\Trash")
    mail.store(",".join(i), "+FLAGS", "\\Deleted")
    print(".")

    if counter % 10 == 0:
        mail.expunge()
        print("Processed " + str(counter * CHUNK_SIZE) + "/" + str(length))
    counter += 1

# Final expunge to make sure everything is committed.
mail.expunge()
print("Done.")