Wrote an iCalendar downloader

Tonight I wrote my first app with the Calendar API. Basically I used the calendar.c demo code as a reference, and pulled out the pieces I needed to do a quick iCalendar download app. It worked without a hitch. With just a little more tweaking, I’ll have a command-line app I can use to fetch arbitrary date ranges in iCalendar format.

The caveat: It’s very slow with date ranges of more than just a few days. I guess that’s to be expected, given the performance I’ve seen with iCalendar downloads from the GUI client. It does eventually come back, though. A one-month range took a few minutes to complete; I hate to think how long three years would take!

Of course, I plan to run this unattended from cron, so in theory I don’t care how long it takes, even if it’s a couple hours. The question is, if I try to suck down a three-year range in one big chunk, will it fubar the calendar server? Obviously that would not be good. The other option would be to pick a manageable chunk, say a few months, and only download that much at a time. I could just run it in a loop until I get the full 3 years. Will have to play with this.

The other puzzler here is, the Oracle Calendar GUI calendar lets me download in either of 2 formats: iCalendar or something it calls “vCalendar”. I’m not sure of the exact difference, but vCalendar is a lot faster to download. What’s the difference between the two, and is there a way of doing the vCalendar download from the API? I wonder if there are certain iCalendar fields that take significantly longer to process. If the vCalendar download omits those, that could speed things up significantly.

I suppose the thing to do is generate both iCalendar and vCalendar dumps for a specific date range, and compare the differences between the two. That may shed some light on things.