[POLL] Cyrus 2.3.x and CONDSTORE

Phil Pennock info-cyrus-spodhuis at spodhuis.org
Sat Jul 8 12:33:07 EDT 2006

On 2006-07-08 at 12:22 -0300, Marc G. Fournier wrote:
> Stupid question, but what *is* CONDSTORE? :)

New extension, part of the IETF's LEMONADE working group's work to make
SMTP+IMAP more usable with small devices like mobile phones, with low or
expensive bandwidth and which disconnect a lot.

Every change to a mailbox has a modification sequence number, which is
associated with whatever bit of data or metadata was modified.  The
mailbox tracks the highest modseq seen.  An individual mail might (but
doesn't need to) support different modseq values on different metadata.

STORE and FETCH can be modified to be conditional upon whether the
modseq has changed since a supplied value, STATUS can return the highest
value, etc.

4551 IMAP Extension for Conditional STORE Operation or Quick Flag
     Changes Resynchronization. A. Melnikov, S. Hole. June 2006. (Format:
     TXT=50265 bytes) (Updates RFC3501) (Status: PROPOSED STANDARD)

and you might also find 4549 useful for background information; RFC 4550
also covers some related work and there's more to come.

4549 Synchronization Operations for Disconnected IMAP4 Clients. A.
     Melnikov, Ed.. June 2006. (Format: TXT=75417 bytes) (Status:

LEMONADE's work: so far, it's already within standards to be able to
construct an SMTP message body from multiple remote parts, getting the
SMTP Submission server to retrieve components from IMAP using URLs
containing access tokens to grant a (or some particular trusted) server
access to one specific bit of data, etc.  RFCs 4467, 4468.  So you can
send that huge MS Word document from your IMAP folder, extracting it as
required, as part of a new message, without the MUA having to actually
retrieve it.  This is also where CATENATE comes from.

Lots of interesting stuff from a utility point of view, but given
software reliability and stability in general the security consequences
are ...  thought-provoking.
"Everything has three factors: politics, money, and the right way to do it.
 In that order."  -- Gary Donahue

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