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pythonimapfetchimaplibimapclient

Pythons imaplib: fetch command, with or without parentheses, 'Invalid Fetch attribute' error for ALL item

I am trying to fetch messages from my IMAP server. This is a short version of my code:

>>> import imaplib
>>> m = imaplib.IMAP4_SSL(host='my.host.com')
>>> m.login('username', 'password')
>>> m.select('INBOX')

The imaplib module in python3.4 is compatible to the RFC 2060 Standard. There it says:

The FETCH command retrieves data associated with a message in the mailbox. The data items to be fetched can be either a single atom or a parenthesized list.

Now I get some different results, which I cannot understand:

>>> m.fetch('1613', '(ALL)')
imaplib.error: FETCH command error: BAD [b'Invalid Fetch attribute ALL']

>>> m.fetch('1613', 'ALL')
('OK', [b'1613 (FLAGS (\\Seen) INTERNALDATE' ... etc ...

>>> m.fetch('1613', '(FLAGS)')
('OK', [b'1613 (FLAGS (\\Seen))'])

>>> m.fetch('1613', 'FLAGS')
('OK', [b'1613 (FLAGS (\\Seen))'])

>>> m.fetch('1613', '(FLAGS ENVELOPE)')
('OK', ... etc ...

>>> m.fetch('1613', '(FLAGS ALL)')
imaplib.error: FETCH command error: BAD [b'Invalid Fetch attribute ALL']

Can someone explain to me why I cannot use the ALL item with the parentheses?

The reason why I am asking is because I am using the IMAPClient module, which automatically adds the parentheses to the parameters, and therefore the ALL item won't work.

Solution

  • ALL isn't a fetch item, it's a macro. A bit a special case in the syntax. There are two others, FAST and FULL. They're like fetch items but with some extra restrictions, one of which you've run into.

    I suggest that you just use the equivalent fetch items and you'll get the result you want without having to deal with the special restrictions. From RFC3501:

      ALL
     Macro equivalent to: (FLAGS INTERNALDATE RFC822.SIZE ENVELOPE)

  FAST
     Macro equivalent to: (FLAGS INTERNALDATE RFC822.SIZE)

  FULL
     Macro equivalent to: (FLAGS INTERNALDATE RFC822.SIZE ENVELOPE BODY)