Backends

Posted Mar 24, 2004 4:45 UTC (Wed) by rickmoen (subscriber, #6943) [Link]

gdt wrote:

The ical (no relation, see IETF) protocol and file format, used by iCal (no relation, see MacOS X) and others is the IMAP of calendaring.

Amen to that, sir. This is why my own comprehensive survey of scheduling software options on Linux starts with a discussion of the IETF standards (iCAL file format, iTIP event-access, iMIP transport, and CAP/BEEP network access), proceeds to a detailed examination of server-end implementations, and only then details client-end software options.

One serious impediment I encountered was, in a sense, Jon's old friend, the now-unmaintained "ical" tk/tcl program by Sanjay Ghemawat: Its name confuses people, because of high similarity to that of IETF's iCAL (RFC2445) data-storage format (aka ".ics") for scheduling data. Ghemawat's old "ical" program does not store its data in iCAL format; the two worlds of data are just about completely incompatible. (There was a half-hearted effort at a conversion script, but it worked only in one direction and was seriously buggy.)

In any event, the future of serious efforts in this field, especially on Linux and especially in open-source coding, lies in the IETF protocol and file-format suite. Effort in that area has been impeded by (1) lack of awareness of the problem, (2) confusion about what "iCAL" does and does not mean, and (3) a shortage of reference implementations for the server end.

Server end:

• If you don't mind proprietary code, you can (cheaply) buy Sun Java System Calendar Server (Solaris SPARC today, but Linux port available soon), or ScheduleWorld.
• On the open-source side, ICAP server (based on libmcal) almost kind of works. Kapor's Open Source Application Foundation claims it'll do a server-end piece whenever it finishes Chandler.
• And there's half a dozen other projects that implement parts of the IETF suite, along with a couple of dozen others that don't even try, or that consider it more important to be an ersatz Exchange Server for MS-Outlook users.

Someone else in this discussion was asking rhetorically whether Chandler will ever matter: Chandler plus the planned matching server-end piece will, if finished in some reasonable time-span, matter a great deal.

One piece that's given me trouble, but that I expect to fix soon, is bidirectional conversion between PalmOS Datebook and iCAL (".ics") format. The latter, just to make sure the point sinks in, is the crucial lingua franca for scheduling data. On the server end, absent a real solution, I can make do with half-measures like PHPiCalendar (an excellent Web-based viewer for multiple .ics files, with no free/busy negotiation, notification or agenting abilities, etc.), and I can edit iCAL data in Mozilla Calendar or any of several other Linux/X11 apps, but if the events don't end up in my PalmPilot, they're pretty useless to me. Based on Jon's report, KOrganizer w/jPilot might finally bridge that gap for me.