dovecot - Sep 2005 - qpopper UIDLs and migrating to dovecot/maildir

hi all,

I am hoping to convert a 350K user qpopper installation using mbox to
dovecot and maildir (pop3 only).

many of the users "leave mail on server", and qpopper's UIDL
format
isn't (yet) supported by dovecot. since the UIDLs have been written by
qpoppper to the existing mbox files (and will be preserved when the
mboxes are converted to maildir) it would be possible to do this
seamlessly if dovecot could read the UIDLs from the messages and
populate the index files as needed.

is anything like this already possible? it doesn't matter what UIDLs
new messages get, since they would never have been downloaded by the
user via qpopper.

any ideas would be appreciated.

grant.

On Thu, Sep 01, 2005 at 10:23:28AM +1000, grant beattie wrote:
> is anything like this already possible? it doesn't matter what UIDLs
> new messages get, since they would never have been downloaded by the
> user via qpopper.
one possibility is to create the dovecot indexes at mbox -> maildir
conversion time, preserving the UIDLs from the mbox file.

perhaps someone has done this before?

grant.

Hi Chris,

We migrated to Dovecot from Qpopper/UW-IMAP in July.  We previously 
looked at altering the Dovecot code, client-side duplicate email cleanup
utilities (for Eudora), and enforcing "download-then-delete from the 
server" prior to the migration.

We got around the "downloading of previously downloaded emails"
problem
by moving all previously downloaded emails to a new folder called 
"ConvertedMail" during the conversion process from mbox (Qpopper) to 
maildir.
This assumes you're going to maildir though.  The benefit in this is 
that the POP client only retrieves email from th inbox folder, and after 
conversion, this will mean only new emails.  If the POP client's 
previous download of older email dissappeared
(for whatever reason), a Web Mail client accessing the mailstore via 
IMAP would allow access to the ConvertedMail folder.

Regards,
Paul

OK, here's the patch against dovecot-1.0-stable. (I just applied it to
dovecot-stable-20050901. My version of stable has a few more patches
applied, so I needed to apply the patch to a clean version!)

Best Wishes,
Chris

grant beattie wrote:
> On Sun, Sep 04, 2005 at 12:30:27AM +0100, Chris Wakelin wrote:
> 
> 
>>Right! Here's a patch against dovecot-1.0.alpha1 which adds an extra
option:
>>
>>pop3_reuse_xuidl = yes
>>
>>which if set will use the contents of the (first) X-UIDL header, if it 
>>exists, instead of the result of expanding pop3_uidl_format. It will use
>>pop3_uidl_format if there is no X-UIDL header.
>>
>>This is typically for people migrating from Qpopper who don't want
their
>>users to get all the mail they've left on the server a second time,
but
>>should also work for any other POP server that happens to write X-UIDL 
>>headers, if any such exist ;)
>>
>>I've only done rudimentary testing, but it seems to work! I also
have a
>>version of the patch for dovecot-1.0-stable (which is what we'll be 
>>using next week!) if anybody's interested (only minor differences,
use
>>'mail->get_header(mail, "X-UIDL")' instead of 
>>'mail_get_first_header(ctx->mail, "X-UIDL")')
> 
> 
> this is great stuff, thanks!
> 
> I'm using the 1.0alpha1 diff and it seems to be working fine so far.
> as we will probably be running 1.0 stable in production, would you
> mind forwarding me the diff against 1.0 stable?
> 
> this is an extremely useful feature, making it even easier to migrate
> from alternate POP3 servers than Dovecot already is. :)
> 
> grant.
> 

-- 
--+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+-
Christopher Wakelin,                           c.d.wakelin at reading.ac.uk
IT Services Centre, The University of Reading,  Tel: +44 (0)118 378 8439
Whiteknights, Reading, RG6 2AF, UK              Fax: +44 (0)118 975 3094
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