show_large_emails.py

"""Lists all e-mails for a given IMAP account, largest first. Can be useful when freeing up space.

Requires imapclient==2.1.0 and python3.6 or higher.
"""

from collections import namedtuple
from email.header import decode_header

from imapclient import IMAPClient

HOST = 'imap.example.com'
USER = 'username'
PASSWORD = 'password1234'

Message = namedtuple('Message', ['id', 'subject', 'date', 'size', 'folder'])


def main():
    messages = []
    with IMAPClient(HOST) as client:
        client.login(USER, PASSWORD)
        for _, _, folder in client.list_folders():
            print('Scanning folder %s' % folder)

            client.select_folder(folder)
            message_ids = client.search()
            response = client.fetch(message_ids, ['ENVELOPE', 'RFC822.SIZE'])

            for message_id, data in response.items():
                envelope = data[b'ENVELOPE']
                size = data[b'RFC822.SIZE']
                subject = get_subject(envelope)
                message = Message(id=message_id, subject=subject, date=envelope.date, size=size,
                                  folder=folder)
                messages.append(message)

        messages = sorted(messages, key=lambda m: m.size, reverse=True)
        for message in messages:
            print(message)


def get_subject(envelope):
    subject = None
    if envelope.subject:
        subject_data = envelope.subject.decode()
        subject_encoded, subject_encoding = decode_header(subject_data)[0]
        if subject_encoding is not None:
            try:
                subject = subject_encoded.decode(subject_encoding)
            except LookupError:
                # Subject cannot be decoded
                subject = subject_encoded
        else:
            # Subject is already decoded
            subject = subject_encoded

    return subject


if __name__ == '__main__':
    main()