Freebusy Aggregator Overview
The freebusy aggregator was built as a proof of concept when responding to an Open Messaging challenge brought to us by Boeing.
As CalDAV has developed the need for a special aggregator has diminished. Already work on server-to-server is covering some of the area covered by the aggregator and lightning together with CalDAV enabled servers can provide most of what the freebusy aggregator provided.
Accordingly, the freebusy aggregator project is now no longer included as part of the bedework release. The last release to include it was 188.8.131.52(a)
The problem to be solved
The problem faced, especially by large multi-national organizations is that of setting up conference calls across multiple timezones. Boeing determined that, if an organizer could determine a free time slot, available to all, or sufficient, potential attendess, then most of the problem has been solved.
The aggregator is a web based client which maintains group and potential attendee information. For each attendee, sufficient information is maintained to allow a request for freebusy information to be made. It is assumed that attendees will use a wide variety of calendar systems. Currently there is no standard protocol which will cover all these systems. The decision was taken to use CalDAV as the only protocol the aggregator would use and to front-end non CalDAV calendar systems by a simple CalDAV proxy.
This approach is manageable because we do not have to implement the full CalDAV protocol, not even a large part. For the first passs at this problem we only require that the server respond to a freebusy request on a specific URL.
Supported Calendar Systems
For the first live demonstration of the aggregator the following systems were supported:
- Bedework - native CalDAV
- Chandler - native CalDAV
- Domino - CalDAV proxy
- Exchange - CalDAV proxy
- Google - CalDAV proxy
- Oracle - native CalDAV
- Timebridge - native CalDAV
Since then we have demonstrated support for the additional systems:
- Apple - native CalDAV
Authentication and SSL
The freebusy aggregator supports ssl and CalDAV authentication (http basic authentication). Currently, for the demo system we do not support passing that authentication through to the targetted systems. The manner of handling this would probably depend upon the targettted system. One approach is to regard the CalDAV proxy as a trusted system and give it access to the required information.
In the demonstartion version, all CalDAV proxies run locally in the quickstart tomcat and use the local system for authenticatiuon (i.e conf/tomcat-users.xml).