on 3/12/2003 2:42 AM David Woodhouse wrote:
> On Wed, 2003-03-12 at 06:58, Eric A. Hall wrote:
> 
>>I'm not trying to start a religious war here, but how much work would it
>>really be to have a protocol extension which allowed the client to request
>>flags which have changed since <time>. It seems that all of the difficulty
>>would be in the implementation (the server data-store), not in the
>>protocol, and there would be significant benefits to having this option
>>available in the protocol. Faster resynchronization between sessions would
>>be very good for all clients, online and offline alike.
> 
> I'm going to assume you meant something sane when you said <time>, of
> course :) 

Uh, heh, I meant time alright. Specifically have the server return a
timestamp whenever a folder is closed, and let the client cache it. On
reconnect, the client can just ask for all messages with a modification
timestamp later than the last-cached value for that folder. For rich
data-stores, this just requires a last-modified-on attribute for each
message record; return those records which have a last-modified-on value
greater than the requested value.

> The protocol side could be fairly simple -- the idea that Timo Sirainen
> offered in <[EMAIL PROTECTED]> seems fairly close to
> what we'd want. You'd declare that a server supporting FLAGS-VALIDITY
> _MUST_ include any messages with changed flags in its response, and
> SHOULD make an effort not to include messages _without_ changed flags.

Doesn't this require the server to cache client state? It'd be a lot
simpler for the clients to keep track of their own state, since that's
what they're already doing.

-- 
Eric A. Hall                                        http://www.ehsco.com/
Internet Core Protocols          http://www.oreilly.com/catalog/coreprot/

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