Web Services has changed how XML data can be retrieved from the Calendar. Currently all web queries that start with "/calendar/Calendar", "/calendar/CalendarGrid", and "/calendar/Search" and use the web query parameter XSL=NONE will continue to work until June 1st, 2011. If you wish to migrate to the new Calendar XML please note the following:
New Calendar Schema:
Example of how to query for XML data (replace the 7 with your calendar ID):
How often will this schema change?
The schema used to extract event data is not the same schema we use to display the calendar. We have a hidden schema that contains many more fields that relate specifically to display data. We created two separate schemas so that as we make changes to how the calendar looks we won't impact those groups consuming our data. Since this schema only contains the necessary data for events we do not anticipate changes being made.
More specific queries
Using the "search" tab from the public calendar web interface you will notice that there are many web parameters used when searching.
Any of these parameters can be added to the web query "/calendar/eventXML/#.xml" in order to filter the results. The web parameter "searchEventType" can be used more than once.
Web Services is in the process of expanding the calendarws.xsd schema to include the ability to insert, update and delete events from the Web Services Calendaring system. I will be posting an email within the next week or so outlining the specifics. I made a point to create a specific complex type called PublicEventWS for the display of event data. By doing this if there are changes made to other elements relating to inserting, updating or deleting events there will be no impact for those consuming only public events.
Since we are just releasing the calendarws.xsd schema there might be requests for changes. Please be advised that the new XML public calendar schema will not be considered "locked down" until Feb 1st.