Webmail application that doesn't abuse the IMAP server?
mills at cc.UManitoba.CA
Tue Jun 10 23:11:31 EDT 2003
On Tue, Jun 10, 2003 at 09:27:13PM -0400, Ken Murchison wrote:
> Gary Mills wrote:
> >Does anyone know of an e-mail web application that doesn't abuse the
> >IMAP server by making short connections? Most of them simply connect
> >and disconnect with each HTTP transaction. Is there one that behaves
> >the same as an IMAP client, using one connection for the duration of
> >the session. An IMAP proxy is not adequate because most of them only
> >cache TCP connections and perhaps authentication. These are generally
> >not the source of most of the transaction overhead.
> So what part of the connection to you perceive as the most expensive?
> The selection of the mailbox? This might be cacheable, but that depends
> on how the webmail client is written (ie, simply caching it might screw
> up some of the client's logic).
I haven't determined that. I suspect, though, that there are limits
to what can be cached by a proxy. A better design might involve a
persistent portion of the webmail application, that maintains some
state across HTTP transactions. The communications between the two
portions need not involve IMAP.
> FWIW, Dave McMurtrie's imapproxy (http://www.imapproxy.org/) works quite
> well with IMP/Cyrus, and is very well written. It doesn't cache the
> selected mailbox, but it does keep an authenticated (and optionally
> encrypted) connection open with the server.
We do use that, and it probably does improve performance. It does have
a problem with idle browser connections that accumulate with time.
This also ties up a lot of `imapd' and `httpd' processes. It probably
needs a client timeout someplace. I haven't had time to investigate
-Gary Mills- -Unix Support- -U of M Academic Computing and Networking-
More information about the Info-cyrus