mswatch [LWN.net]

mswatch

Posted Oct 7, 2009 0:00 UTC (Wed) by ChrisFrost (guest, #61105)
In reply to: offlineimap by k8to
Parent article: Stresstesting IMAP clients (Hackvalue)

If you sometimes wish that you were notified of new mail before the next two
minute polling period or sometimes wish the polling used less bandwidth, you
might be interested in http://mswatch.sourceforge.net/. mswatch invokes mail
synchronization programs when it detects changes to the local or remote
mailbox. (Bias note: I wrote mswatch.)

to post comments

mswatch

Posted Oct 7, 2009 0:13 UTC (Wed) by dlang (guest, #313) [Link] (4 responses)

1. IMAP probably doesn't need anything like this as the protocol supports efficient checking of messages

2. if you avoid polling, how do you find out that the remote mailbox has changed?

mswatch

Posted Oct 7, 2009 0:26 UTC (Wed) by ChrisFrost (guest, #61105) [Link] (3 responses)

1. If the IMAP account contains hundreds or thousands of folders, the client
and server would need that many open sockets (for the IDLE command).
Additionally, the server may have multiple clients, each doing this. Also, I
don't happen to know of any clients that maintain an IMAP connection for
each folder (Mail.app, Thunderbird, mutt, and mbsync, at least). mswatch
improves on the IMAP protocol by using one socket, and only one inotify file
descriptor, for an arbitrary number of folders.

2. mswatch asks the kernel to inform mswatch when files change, using the
inotify or dnotify interface.

mswatch

Posted Oct 9, 2009 13:10 UTC (Fri) by job (guest, #670) [Link] (2 responses)

The IMAP protocol needs to be fixed so many IDLE commands can be active simultaneously or given the ability to IDLE over several mailboxes, whatever is best protocol-wise. This should be fixed in the most common implementations. IMHO, kludges will only make that work more difficult.

mswatch

Posted Oct 9, 2009 14:48 UTC (Fri) by ChrisFrost (guest, #61105) [Link] (1 responses)

FYI, the mswatch page discusses all these points that you have raised, in
its "Why mswatch" section :).

"The author of IMAP, Mark Crispin, does not see this capability [multi-
mailbox IDLE] as belonging in IMAP. He states that multiple mailbox
notification belongs in a separate protocol designed for event notification
[http://www.webservertalk.com/message1459531-1.html#post40... ]."

FYI, the Lemonade working group is working on such a protocol. But this is
still in the works. http://www.ietf.org/html.charters/lemonade-charter.html
Hopefully one day mswatch will only poorly duplicate commonly available
functionality. But until then, mswatch is already available.

mswatch

Posted Oct 10, 2009 2:35 UTC (Sat) by foom (subscriber, #14868) [Link]

> The author of IMAP, Mark Crispin, does not see this capability [multi-
> mailbox IDLE] as belonging in IMAP

Be that as it may,
http://tools.ietf.org/html/draft-ietf-lemonade-imap-notif...