I have not been able to put a lot of effort into DAViCal over the last couple of months, since my father was diagnosed with stomach cancer in early September, and he died on 2nd October.

So here it is, finally, including a lot of refactoring work around the handling of DAV/CalDAV REPORT requests and implementation of the DAV::principal-property-search report. This also requires an upgrade to the latest AWL library (0.20), which includes a complete rewrite to the class used for parsing and rendering iCalendar data.

This release is recommended, since you will need some of this stuff to support the upcoming Mozilla Calendar 0.7 release properly.

At this point I have only released the files to http://debian.mcmillan.net.nz/ and I'll push it out to a wider audience if I don't here screams of anguish from people in the next few days :-)

This release does not have any associated database changes, so it should be a simple matter to install the upgraded code.

After much wading through possible names, none of which really excited me, I have finally chosen "DAViCal" as the new name for my CalDAV server that was previously called RSCDS, or the "Really Simple CalDAV Store".

In the end, I chose DAViCal because it:

• seems easy to pronounce.
• combines the 'Cal' and 'DAV'.
• returns < 1000 results on google.
• doesn't make me cringe.
• didn't have a domain name registered.

That was about the hardest part of preparing for the 0.8.1 release, and now that I've done that I should manage to make the changes to the packaging, though I have no doubt that the old name will appear in all sorts of places for a while yet.

Choosing names is an important business, and I should know that from the length of time we spent agonising over names for our children, discarding all sorts of things because they had silly abbreviation collisions (like the "Royal Scottish Country Dance Society" :-) Even then, I think we got the kids names wrong, and the big one should be called "Thumper" with the little one called "Sly", but perhaps that's just a temporary annoyance and in time the names that we registered for them will fit them better.

I also recall Grant once saying that you should never use the word "Simple" in the name of your project, and he should know. DAViCal is no longer particularly simple, although I have attempted to hide the complexity from the user as far as that is possible, and will continue to do so.

Once I get out version 0.8.1 of DAViCal I will finally upload it to Debian, proper. This version has some important enhancements to its DAV spec compliance which are going to be needed by some future versions of Mozilla, and probably other things too, so it's important to push it out as soon as possible now.

Having taken time out to go to the other side of the world to attend DebConf 7 in Edinburgh, and then after spending some time with my family, I have been somewhat distracted from things CalDAV for a wee while now. There are signs that I will be able to put a few more evenings and weekends into it in coming months.

Current Status

With the release of 0.8.0 I believe it is quite a usable application for shared group calendars. We use it at Catalyst for about 80 staff and, while we're not heavy calendar users, it manages without any noticeable performance problems.

There have been an impressive number of downloads from Sourceforge, as well as substantial downloads from my Debian repository, and I believe that the program is in tens, if not hundreds, of installations.

Future Plans

In the immediate future I want to get the basic framework for querying properties about the owner of a calendar or a set of calendars. This will be used by Mozilla soon during their configuration of a new CalDAV source, and I think that Apple iCal probably uses them already. This is partly done, but it's implementation has been slowed by the necessity to refactor the handling of the REPORT method in general to make the code more modular and readable, and to support queries and properties in a more general manner.

The refactoring of the REPORT method handling is in place now, so moving on to the handling of DAV:principal objects should become fairly straightforward. I may end up with a fair bit of quiet, undistracted time over the coming weekend so if I can get in the 'zone', it may get done, and we can start rolling towards a release 0.9.

Release 0.9 will have a new name. One from the cast of thousands that have been submitted to me so far, or one that I will hastily think up in between, but the next released version will not be called RSCDS any longer.

The main goals for further into the future are:

• Maintain interoperability with clients
• Improve specification compliance
• Extend coverage to related specifications
• Documentation improvements
• Configuration improvements
• Installation improvements

Interoperability

I think that RSCDS does fairly well on the interoperability front. Unfortunately I have no access to the preview of OS 10.5, with it's native CalDAV client (though I have been told that it works with RSCDS). Likewise, other commercial CalDAV clients aren't available to me for testing either, so I have concentrated my efforts on supporting the featureset used by the various free CalDAV clients.

My initial work focused around supporting Evolution, in particular, but with the recent effort put in by the Mozilla Calendar team the primary interoperability challenge is to enhance RSCDS to support their areas of development. If I could see how the OS 10.5 client behaves, too, I believe that would help identify a few points to extend, as well as suggesting some future directions.

The best place to review interoperability would probably be at the CalConnect Roundtable 10 but I think that without some sponsorship for airfares I probably won't be able to make that. Maybe next time.

Specifications Compliance

As I read, and reread, the CalDAV (and DAV, and HTTP, and ...) RFCs the compliance with the various specifications improves. Recently I have put a lot of work into the calendar-query report, in particular, which means it now supports querying against arbitrary properties much more comprehensively. This is important because some of the client software is starting to do arbitrary queries also, and it is inevitable that queries for the classification of events, or the percentage completion of todo items will become more common.

And now I notice that there is a new version of DAV in RFC4918, though not too many changes as far as I can see. The intent of this release is mostly to clarify, and slightly to extend, primarily in order to improve client interoperability.

Coverage of Related Specifications

In terms of general calendaring activities, the biggest hole in the CalDAV specification at present is standardisation around the location of other people's schedules. The current draft of the Scheduling Extensions to CalDAV appears to address that, and a lot more besides. I expect to start working on parts of this at some point, but perhaps not sooner than I see a client which starts using it, or when it is ratified, whichever occurs soonest.

Documentation

The documentation is OK. The wiki, in particular, is a reasonable resource for resolving problems (I believe), but it would be good to have some documentation of other things.

One area that could do with enhancement is some documentation of how to check out a copy of the code, and how to provide patches back to me. Even better if other people can maintain their own trees which I could pull patches from, since we're using a distributed version control system (Git) to start with.

Configuration

The administration interface for RSCDS is OK, but could do with a few improvements to make it more usable. Really there are not a lot of reasons to be in the administrative interface, so these improvements should be relatively few, and relatively easy.

This would be a good area for someone interested in helping out to become involved, because it does not entail reading large reams of RFCs, or watching tcpdumps scroll past for the debugging.

Installation

One thing that I have done right, I believe, was to provide the software from the beginning in a packaged form to make the installation easier. Although the software is packaged for Debian, however, it has not yet been uploaded to the archive because I have been waiting for the webapps-common package to enter Debian so I can use that for configuration.

I think I have waited long enough though, so I will upload the next version to Debian for use by a wider audience.

Security

Security has always been a focus for me and I have had the code reviewed for any obvious security flaws. If any particular vulnerabilities are found they will be addressed with appropriate haste.

Retrospective

I've been working on this for a little over a year now, and I think I have largely met my goals for the project. It has certainly been an educational experience for me, and the effect of this work on other projects that I also participate in has also been valuable.

Any new open-source project is always at risk of the developer losing energy and interest, but I believe this one has made it to a state where the bulk of the infrastructure effort has been done, and there are enough interesting challenges in the future to continue to keep me (at least) working on it into the future.

The scope of this project is good, in that it is not at risk of expanding to take over the world. The intention behind this is simply to provide a back-end service for client software which should be very much Someone Else's Problem. In reality there have been times when I have had to get to grips with some of that client software in order to resolve problems, but those have by and large been good experiences.

I see that Jari Urpalainen has written an CalDAV Apache module to support some basic CalDAV functionality.

Excellent.

Meanwhile my own CalDAV server is going through a period of stabilisation before I start in on some of the handling of "Principals", probably next month.

And CalDAV has become RFC 4791 now too.

Here at LCA it seems that some people want shared calendars, so I'm pleaased to be able to tell people that I have spent the last 9 months thinking about and writing a CalDAV server.

While it isn't finished yet (is software ever finished?), it does work just fine with all of the free CalDAV clients that are available, and a number of nice people have translated it into six languages so far.

So if you are at LCA and want to know more catch me at tonight's penguin dinner.