Re: [Imaplib2-devel] recovering message numbering for EXISTS and EXPUNGE

[Kerry K. <kk...@gm...>]

On Mon, Jan 30, 2012 at 5:37 PM, Ross Boylan <ro...@bi...> wrote:

> I think that it is not possible to reconstruct exactly which messages
> were added and removed in some circumstances.  Is my understanding
> correct?
>
>
That is my understanding as well.


> If this sequence came back from the server
> * 4 EXPUNGE
> * 5 EXISTS
> then the new message is sequence 5.
>
>
Assuming you're in an IDLE, yes. If you got that in response to a UID
FETCH, for example, then it'd mean that 5 messages exist... but not
necessarily that message 5 is new.


> If this sequence came back
> * 5 EXISTS
> * 4 EXPUNGE
> then the new message is sequence 4.
>
>
Correct (again assuming you're in an IDLE). The sequence numbers above the
expunged message decrement immediately. RFC 3501, 7.4.1.


> Since imaplib2 only gives the relative time sequence within a single
> class of untagged response (i.e., EXPUNGE or EXISTS) there is no way to
> tell which of these scenarios happened assuming one recovers the 2
> separate responses.
>
>
So far as I can tell this is also correct. And for what it's worth the
original imaplib behaves the same.


> For my purposes that level of detail is probably not necessary; I can
> just err on the side of caution.
>
> Perhaps imaplib2 should have a callback that would enable tracking the
> exact sequence of messages.
>

You can monkeypatch imaplib2 to keep track of the exact sequence of
untagged responses.

Here's the patch that I applied to imaplib... You should be able to adapt
it for imaplib2:

def patch():
    imaplib.IMAP4._append_untagged = _append_untagged

def _append_untagged(self, typ, dat):
    ##
    # The original code
    if dat is None: dat = ''
    ur = self.untagged_responses
    if __debug__:
        if self.debug >= 5:
            self._mesg('untagged_responses[%s] %s += ["%s"]' %
                    (typ, len(ur.get(typ,'')), dat))
    if typ in ur:
        ur[typ].append(dat)
    else:
        ur[typ] = [dat]
    #
    ##

    ##
    # The new code
    try:
        self.ordered_untagged_responses.append((typ, dat))
    except AttributeError:
        self.ordered_untagged_responses = list((typ, dat))
    #
    ##


With all of that said, Piers might be aware of something that we're not...

Cheers,
-K


>
> Ross Boylan
>
>
>
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