Parsing Message-ID header returned by imaplib

Question

I'm fetching the messageid from emails in Gmail via IMAP.

This code:

messageid = m.fetch(num, '(BODY[HEADER.FIELDS (MESSAGE-ID)])')
print messageid

returns this:

[('1 (BODY[HEADER.FIELDS (MESSAGE-ID)] {78}', 'Message-ID: <actualmessageid@mail.mail.gmail.com>\r\n\r\n'), ')']

How would I parse just the actual message-id out of that?

Answer 1

You can also achieve what you want using the email module's HeaderParser.parsestr() function (same API as Parser but doesn't worry about the email's body) and the parseaddr() function.

>>> from email.parser import HeaderParser
>>> from email.utils import parseaddr

>>> hp = HeaderParser()

>>> response = [('1 (BODY[HEADER.FIELDS (MESSAGE-ID)] {78}',
                 'Message-ID: <actualmessageid@mail.mail.gmail.com>\r\n\r\n'), ')']

>>> header_string = response[0][1]

>>> header_string
'Message-ID: <actualmessageid@mail.mail.gmail.com>\r\n\r\n'

>>> header = hp.parsestr(header_string)

>>> header
<email.message.Message instance at 0x023A6198>

>>> header['message-id']
'<actualmessageid@mail.mail.gmail.com>'

>>> msg_id = parseaddr(header['message-id'])

>>> msg_id
('', 'actualmessageid@mail.mail.gmail.com')

>>> msg_id[1]
'actualmessageid@mail.mail.gmail.com'

Thus:

from email.parser import HeaderParser
from email.utils import parseaddr

hp = HeaderParser()

def get_id(response):
    header_string = response[0][1]
    header = hp.parsestr(header_string)
    return parseaddr(header['message-id'])[1]

response = [('1 (BODY[HEADER.FIELDS (MESSAGE-ID)] {78}',
             'Message-ID: <actualmessageid@mail.mail.gmail.com>\r\n\r\n'), ')']


print(get_id(response))

returns:

actualmessageid@mail.mail.gmail.com