Download all attachments from Gmail from a specific sender

download_attachments_from_sender_gmail.py

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# THE SOFTWARE.

import email, getpass, imaplib, os, sys

# The following script will download all attachments from a given sender
# that you specify. Little to no error handling, use at your own risk!
#
# IMPORTANT: If you first used Gmail in the UK then you need to select
# a different mailbox (please see below and uncomment the appropriate line).
#
# Adapted from http://stackoverflow.com/questions/10182499/how-do-i-download-only-unread-attachments-from-a-specific-gmail-label

# Directory where to save attachments ('.' = current directory)
detach_dir = '.'

user = raw_input("Gmail username: ")
pwd = getpass.getpass("Password: ")
sender_email = raw_input("Enter the sender's email (to filter by): ")

# Connecting to the gmail imap server
m = imaplib.IMAP4_SSL("imap.gmail.com")
m.login(user,pwd)

# Select the mailbox
m.select("[Gmail]/All Mail")

# If you get an error "command SEARCH illegal in state AUTH, only allowed in states SELECTED"
# then it is likely that the mailbox you have tried to select doesn't exist.
# If you were originally a Google Mail user (i.e. a user in the UK) then you should uncomment
# the line below.

# m.select("[Google Mail]/All Mail") # here you a can choose a mail box like INBOX instead

# Alternatively you can search for emails in the inbox only
# m.select("INBOX")

# Use m.list() to get all the mailboxes

resp, items = m.search(None, 'FROM', '"%s"' % sender_email)
items = items[0].split()

for emailid in items:
    resp, data = m.fetch(emailid, "(RFC822)")
    email_body = data[0][1]
    mail = email.message_from_string(email_body)

    if mail.get_content_maintype() != 'multipart':
        continue

    subject = ""

    if mail["subject"] is not None:
        subject = mail["subject"]

    print "["+mail["From"]+"] :" + subject

    for part in mail.walk():
        if part.get_content_maintype() == 'multipart':
            continue

        if part.get('Content-Disposition') is None:
            continue

        filename = part.get_filename()
        counter = 1

        if not filename:
            filename = 'part-%03d%s' % (counter, 'bin')
            counter += 1

        att_path = os.path.join(detach_dir, filename)

        if not os.path.isfile(att_path) :
            fp = open(att_path, 'wb')
            fp.write(part.get_payload(decode=True))
            fp.close()

SOLVED IT 💯

                                                            mail = email.message_from_string(email_body)

The above line in the code must be replaced with the following line and it works perfectly

                                                            mail = email.message_from_bytes(email_body)

in short: "email.message_from_string" must be replaced with "email.message_from_bytes". Because the data is present in bytes not in the string format.

Thanks for that @RahulSapparapu !
In addition to that, I had to make the following minor changes to make it python3 compatible

1. Use input in place of raw_input
2. Use additional single quote at

('"[Gmail]/All Mail"')

4. Use parentheses at

print("["+mail["From"]+"] :" + subject)

Finally, added the following to filename as my attachments were of the same name and were getting overwritten:

datestring = mail['date']
datestring2 = utils.parsedate_to_datetime(datestring).strftime("%Y_%m_%d")
filename = datestring2 + '_' + part.get_filename()

Thank you @styrmis for sharing this!