IMAP protocol help

IMAP protocol help

[Ted Zlatanov]

There's surprisingly few Google-able explanations of IMAP, because the
search terms are very common.  I want a walkthrough that shows how the
protocol works with examples, for all the common functionality up to
newer stuff like NOTIFY and QRESYNC.

The RFCs are spectacularly useless.  I don't know why, but I have read
them several times and they answer "is this formatted properly?" but not
"how does an IMAP conversation look?".  Perhaps it's just me...

This is for gnus-sync and so I can be more helpful understanding and
debugging IMAP in general.  I would greatly appreciate any pointers.

Thanks
Ted

Re: IMAP protocol help

[Lars Ingebrigtsen]

Ted Zlatanov <tzz@lifelogs.com> writes:

> The RFCs are spectacularly useless.  I don't know why, but I have read
> them several times and they answer "is this formatted properly?" but not
> "how does an IMAP conversation look?".  Perhaps it's just me...
>
> This is for gnus-sync and so I can be more helpful understanding and
> debugging IMAP in general.  I would greatly appreciate any pointers.

I think I just looked at what IMAP servers output and then I understood
what the RFCs were talking about.

IMAP is actually pretty neat.  It has tagged commands and explicit
end-of-responses, but not beginning-of-responses, which is the opposite
of most protocols.

So you send a bunch of tagged commands to the server (the tags are
generally numbers), in this case "1999" and "2000".  So you get two
responses back:

* OK [CLOSED] Previous mailbox closed.
* FLAGS (%Answered %Flagged %Deleted %Seen %Draft)
* OK [PERMANENTFLAGS ()] Read-only mailbox.
* 11 EXISTS
* 0 RECENT
* OK [UIDVALIDITY 1296352414] UIDs valid
* OK [UIDNEXT 12] Predicted next UID
* OK [HIGHESTMODSEQ 21] Highest
1999 OK [READ-ONLY] Select completed.
* OK [CLOSED] Previous mailbox closed.
* FLAGS (%Answered %Flagged %Deleted %Seen %Draft)
* OK [PERMANENTFLAGS ()] Read-only mailbox.
* 5 EXISTS
* 0 RECENT
* OK [UIDVALIDITY 1333330711] UIDs valid
* OK [UIDNEXT 6] Predicted next UID
* OK [HIGHESTMODSEQ 25] Highest
2000 OK [READ-ONLY] Select completed.

So a response just starts, and then it ends with the tag and "OK", so
you see that the command is OK.

Instead of SMTP that starts with "OK" and then uses a "." to signal the
end.

But perhaps that's not what you were wondering about.  :-)

-- 
(domestic pets only, the antidote for overdose, milk.)
  http://lars.ingebrigtsen.no  *  Lars Magne Ingebrigtsen

Re: IMAP protocol help

[Alberto Luaces]

Ted Zlatanov writes:

> There's surprisingly few Google-able explanations of IMAP, because the
> search terms are very common.  I want a walkthrough that shows how the
> protocol works with examples, for all the common functionality up to
> newer stuff like NOTIFY and QRESYNC.
>
> The RFCs are spectacularly useless.  I don't know why, but I have read
> them several times and they answer "is this formatted properly?" but not
> "how does an IMAP conversation look?".  Perhaps it's just me...
>
> This is for gnus-sync and so I can be more helpful understanding and
> debugging IMAP in general.  I would greatly appreciate any pointers.

I never had to use that, but I found the thesis document of Trojitá's
email client to be quite instructive
(http://trojita.flaska.net/msc-thesis.pdf), especially about
extensions.  The root page of the project is http://trojita.flaska.net/

-- 
Alberto

Re: IMAP protocol help

[Steinar Bang]

>>>>> Alberto Luaces <aluaces@udc.es>:

> I never had to use that, but I found the thesis document of Trojitá's
> email client to be quite instructive
> (http://trojita.flaska.net/msc-thesis.pdf),

After a quick read-through of the start of the document, I have to
agree.  This is the clearest explanation of UID and UIDVALIDITY &
friends, that I have seen.

> especially about extensions.  The root page of the project is
> http://trojita.flaska.net/

I didn't dig too deep into the extensions part of the document, so I
can't comment here.