Cyrus,

On 2-Feb-07, at 9:55 AM, Cyrus Daboo wrote:

Hi Tyler,

--On February 2, 2007 9:40:18 AM -0600 Tyler Keating <[EMAIL PROTECTED]> wrote:

I have a simple question. Can the Calendar Server act on Alarm triggers?
Such as sending email or an HTTP POST?

No - the server does not do that. I believe some calendar systems do have a server-based automatic alarm system. At some point it would be good to have something like this so that users don't need to have their calendar clients on all the time to receive alarms.

One problem right now is that the alarm definition in iCalendar may not be flexible enough to cover the types of alarm one might need. It does have an email option, but the other types "display" and "audio" only make sense for a client. A better choice might be to have a generic "uri" type that could be used to point to different services (e.g. not only email, but im, telephone, pager etc).

Better still would be to have an actual "alarm server" that is smart in determining exactly how to alert a user at a particular time (e.g. you could configure preferences to have alerts delivered in different ways depending on the time of day, day of the week, whether your IM status indicates you as "present" on a particular machine etc).

All pie-in-the-sky stuff right now, but it would be good to know if people are interested in server-based alarm actions.

--
Cyrus Daboo


I thought as much, thanks. I was hoping to save myself the trouble of creating some sort of "Alarm Daemon", so at least you have one person definitely interested in Calendar Server alarm actions. And when I think about, email alarms only might be the best way to go. Here are my thoughts on it:

Because of my working life at a Telco, I know that there are some unified messaging products that redirect communications based on schedules, similar to what you describe. But there is no way to connect directly between the Calendar Server and the Messaging Server, without a client pulling the strings and some opening up of the Messaging Server API. Doing it all at the calendar server level, I think you would need to extend iCalendar with some new type of Component to describe messaging rules and endpoints (VCONTACT?). So that when a "procedure" VALARM is triggered, the Calendar Server could check to see if the collection has a VCONTACT component and then call the predefined endpoints according to the time and priority or something like that.

This seems so complex to add to a calendar server, that I'm not so sure it isn't better left to a dedicated "Messaging Server" that would front (at least) a Mail server which the Calendar Server could send to when an alarm occurs. The user of the Messaging Server would already have set up their rules for how they want to handle email at that time and from that sender and then the Messaging Server should be able to do things like you say: make a call and translate the email text into speech, make a call and play an attached recording from the email, chop the email into a collection of SMS messages or use it's IM gateway to determine that you're signed in and send you an IM. However, if the Messaging Server doesn't exist, then the Calendar Server's email still goes through.

This way the calendar server would not need a massive extension to know how you want to be contacted when an alarm occurs, it just needs that extra bit of functionality to send email. The only thing this solution is missing is that you have to manage a schedule of messaging rules externally to the calendar server. But that doesn't mean that a client couldn't still display the messaging schedule alongside the user's calendars, especially if the Messaging server supports iCalendar and CalDAV.

I'm pretty new to this and I don't have the whole picture, but I think you should resist anyone's opinion to beef up the Calendar Server beyond email alarms and messing with iCalendar. That said, my alarm daemon could really use that Darwin "Messaging" Server any day now or better yet your newly scoped "email alarm daemon" for Darwin Calendar Server could use it...

Always a pleasure,
Tyler
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