[nzlug] Email 'Checker' that supports IMAP Folders

[Nick 'Zaf' Clifford]

Hadley Rich wrote:
> On Tue, 12 Jun 2007 17:07:08 Nick 'Zaf' Clifford wrote:
>   
>> If I had a choice, I would have used Courier for that feature alone.
>> What I really want is the Dovecot authors to implement this advanced
>> idle command, as I like Dovecot for many reasons :)
>>     
>
> Dovecot does support the IDLE command, I couldn't tell you why you see 
> different behaviour in Thunderbird with Courier than Dovecot but I do know it 
> works.
>
>   
Yup, I know it supports the IDLE, but there is an enhanced IDLE command.
Courier IMAPd calls it IMAP_ENHANCEDIDLE.
>From the imapd man
>
> Setting the |IMAP_ENHANCEDIDLE| to |1| in |/etc/courier/imapd| enables
> realtime concurrent folder status updates. When relatime folder status
> updates are enabled all IMAP mail clients that have the same folder
> open will be immediately notified of any changes to the folder's contents.
>
> The Courier-IMAP server always allows more than one mail client to
> have the same folder opened. However, when two or more clients have
> the same folder opened, the mail clients may not necessarily know when
> another client added or removed messages from the folder. The base
> IMAP protocol specification requires IMAP mail clients to explicitly
> check for any changes to the folder's contents. No provisions exists
> to notify the mail client immediately when the folder's contents are
> modified by another mail client.
>
> The |IDLE| extension to the base IMAP protocol provides a delivery
> mechanism for notifying mail clients of changes to the mail folder's
> contents. Although at this time it's not known to which extent the
> |IDLE| extension is supported by IMAP mail clients, the Courier-IMAP
> server fully implements the |IDLE| extension

There is also a setting called IMAP_CHECK_ALL_FOLDERS, documented as such:
> # Set IMAP_CHECK_ALL_FOLDERS to 1 if you want the server to check for new
> # mail in every folder.  Not all IMAP clients use the IMAP's new mail
> # indicator, but some do.  Normally new mail is checked only in INBOX,
> # because it is a comparatively time consuming operation, and it would be
> # a complete waste of time unless mail filters are used to deliver
> # mail directly to folders.
> #
> # When IMAP clients are used which support new mail indication, and when
> # mail filters are used to sort incoming mail into folders, setting
> # IMAP_CHECK_ALL_FOLDERS to 1 will allow IMAP clients to announce new
> # mail in folders.  Note that this will result in slightly more load
> on the
> # server.
> #

Nick