X-OfflineIMAP header and Exchange

Dominic LoBue dom.lobue at gmail.com
Thu Feb 4 06:52:18 GMT 2010

On Wed, Feb 3, 2010 at 9:46 AM, Dave Mussulman <mussulma at gmail.com> wrote:
> On Wed, Feb 3, 2010 at 2:43 AM, Dominic LoBue <dom.lobue at gmail.com> wrote:
>> On Fri, Jan 29, 2010 at 8:07 AM, Dave Mussulman <mussulma at gmail.com>
>> wrote:
>> > I found http://software.complete.org/software/issues/show/114 but had a
>> > few questions about the patch.
>> >
>> > The patch only seems to address the X-OfflineIMAP-* header when it's
>> > created.  Wouldn't a patch also need to modify wherever that header
>> > gets parsed/read/sync'd?  Or is just changing how it's created good
>> > enough?
>> >
>> > What's the impact of making this change on a large existing sync'd
>> > maildir?  Would my messages show up as new again?  Anything else to look
>> > out for before trying the patch?
>> My point: would you be willing to work with me to resolve this problem
>> once and for all? I'll be able to answer all your questions if you
>> agree.
> Dominic, thanks.  I'm willing to work with you; if I didn't care, I wouldn't
> have mailed the list.  :)
>> If you do not want to work with me, then to answer your question on
>> what effect the patch would have on your existing mail, I see several
>> possible scenarios:
>> 1. All emails using the X-OfflineIMAP header are duplicated.
>> 2. All emails using the X-OfflineIMAP header are deleted.
>> 3. Nothing happens.
>> I don't think there's a chance in hell scenario 3 will occur though.
> I made the change on Monday, and "nothing happened".  I backed up my maildir
> first, but I didn't change the metadata dirs.  As far as I can tell,
> everything's working as before.  No dupes, no deletions, etc.  I made the
> change because I wasn't seeing the headers consistently anyway -- some older
> messages had them, most newer didn't, which I guessed goes back to
> Exchange's mailbox store LHS header store being at or above quota.
> My only weird observation is I don't see the X-OfflineIMAP-* headers on my
> maildir copies of the mail, or when I IMAP in (with Thunderbird or mutt
> directly) but I do see them in Outlook when looking at the message headers.
> My running hunch right now is OfflineIMAP wasn't getting those headers
> anyway, and was running alright without them.  (Although it was setting them
> on the messages it saved back to the server.)
> I confirmed after my change that the new messages sync'd back have just the
> X-OfflineIMAP: LHS header, but again, I don't see that outside of Outlook.
> If you're still interested in my data, let me know and we can take this off
> list.  Thanks.
> Dave


I'm glad to hear that it is working; and yes, I definitely would like
to see your metadata.

As to why your local messages are unmodified, this makes sense
actually. Since the strings that make up  the X-OfflineIMAP header are
generated by calculating a hash of the email itself, putting the
header string into the local copy of the email would change what that
string would come out to the next time the generator is run. Its a
mathematical chicken and the egg dilemma.

This means that either that string is generated from scratch every
time OfflineIMAP needs it, or it is stored in the metadata.

When you email the metadata I highly recommend sending it just to me
instead of the rest of the list.


Dominic LoBue

More information about the OfflineIMAP-project mailing list