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Seeking a Client Independent Calendar Server?

Cliff posted more than 11 years ago | from the wondering-why-this-doesn't-exist-yet dept.

Technology 33

Prep asks: "I work in the IT shop at a small liberal arts school, which has, for a few years now, offered a calendar solution that lets members of the community keep a personal calendar/task list, as well as view/schedule publicly viewable meetings and tasks for other members of the community, as well as campus resources (rooms, projectors, vehicles, etc). The system works pretty well right now, but it's entirely proprietary. What I'm wondering is why the client independent model used by mail servers hasn't been adopted by a calendaring project. With standards like iCal and vCal floating around, it seems to me that the groundwork has been laid for a backend server which could interact with popular clients like Ximian's Evolution, Mozilla's Calendar, Apple's iCal, and even Microsoft's Outlook, giving users the ability to use whatever platform/client they wish, while still maintaining the ability to interact with their co-workers. If the software were tied to an SQL backend, then you could even offer a web enabled front end, perhaps even with a tie in to projects like IMP. Does anyone know of any projects working toward an open standards based end like this?"

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Blame the Clients (2, Insightful)

Gothmolly (148874) | more than 11 years ago | (#5610784)

If the standards exist, its the fault of the client vendor if they don't support them. Commercial vendors (MS) have vested interest in locking users into their proprietary messaging system. There is no financial incentive to broaden their horizons, so to speak. If you want a client-independent calendaring solution, look at something purely web-based. If the HTML is 'standard' enough, every browser on every OS will be able to understand it.

Re:Blame the Clients (1)

Webmonger (24302) | more than 11 years ago | (#5610850)

Even Outlook is supposed to support iCal. It's just that there aren't any alternative iCal servers. Not any I could find when I was looking into this half a year ago. . .

Re:Blame the Clients (3, Informative)

RalphBNumbers (655475) | more than 11 years ago | (#5610883)

What are you talking about?
iCal can serve from any webDAV enabled webserver.

just search "iCal apache" on google or a bunch of howtos

Re:Blame the Clients (1)

Webmonger (24302) | more than 11 years ago | (#5611348)

iCal is a recent product that wasn't available last time I looked. 'Scuuuse me!

Re:Blame the Clients (3, Informative)

babbage (61057) | more than 11 years ago | (#5611420)

No, actually iCal is a fairly old file format (not sure how old, but a few years anyway I think) and Apple's is a new application built around that file format. Libraries for working with iCal, such as Perl's Date::ICal & Net::ICal [] , have been around since at least 2001, under the development of the Reefknot [] calendaring project.

Why Apple gave their application the exact same name as the format I don't know, but in any case the release of the Apple application just gave the iCal format a higher profile than it used to have -- but they certainly didn't invent it all by themselves. :-)

Re:Blame the Clients (0)

IRNI (5906) | more than 11 years ago | (#5611492)

1) because they helped come up with the standard

2) because it fit in well with the rest of their app names.

Re:Blame the Clients (0)

Anonymous Coward | more than 11 years ago | (#5613183)

Why Apple gave their application the exact same name as the format I don't know

The name of the RFC2445 format is iCalendar, not iCal

Re:Blame the Clients (2, Informative)

Webmonger (24302) | more than 11 years ago | (#5611367)

I should also mention that iCal is a protocol (RFC2445) not just an Apple product.

SuSE OpenExchange Server (2, Informative)

agg123456789 (593765) | more than 11 years ago | (#5610966)

What about OpenExchange? It will let you at your email, calender, and contacts via the web and though Outlook...And, probably through the Ximian Connector as well.

My company is considering this to replace a bunch of Sun Qube 3 appliences. It seems as though it could be a nice solution, however I have not had time to do much testing yet.

Check OpenExhcange 4 [] out.

Re:SuSE OpenExchange Server (1)

thilmony (248711) | more than 11 years ago | (#5612162)

if you buy the eval for $19, is it a limited version with no support, or just some trialware? I'd love to play with it at home before pitching it at work!

Re:SuSE OpenExchange Server (2, Informative)

GuardianBob420 (309353) | more than 11 years ago | (#5612303)

I just started using SuSE OpenExchange at my shop, didn't want to deal with MS Exchange or Outlook for that matter. The product is nice; my users are mostly medical types and newbies, and they seem to really like (and to be able to figure out and use) the group calendaring and resource management aspects of the groupware. It's a web based app, so you've got your choice of clients. It's pretty straight forward to set up and install (YaST2) and then administer (web based). My only (very minor) complaint would be that the labels and terminology are a little different than your typical US English ISP's web based email client (probably a translation thing - not wrong or even awkward, just a little different), so I had to explain a few things to the users. Really though, it's definitely worth a look. It appears to be the best complete web based groupware solution right now.

Reefknot (4, Informative)

babbage (61057) | more than 11 years ago | (#5611107)

The closest thing I know of is the ReefKnot project [] , which is among other things responsible for Perl's iCal parsing libraries. The project is kind of stalled, but if you're interested in getting involved feel free to download the software [] (all of which should also be on CPAN) and subscribe to the developer's [] and users [] mailing lists. They're kind of idle these days, but I'm sure any new Slashdot users will kick up a little surge in chatter -- hopefully enough to start making progress again.

I'm personally not clear if Reefknot is meant to be a self-contained iCalendar server, or if it's meant to provide the libraries that can be embedded in an Apache/mod_perl server (the latter makes a bit more sense to me -- that way you can get WebDAV support from mod_dav, Apache's built in authentication mechanisms, etc -- but I'm not sure if that's accurate). In any case though, it gives you some substantial building blocks to start with & use as you see fit. Obviously a more cohesive package would be a nice thing, but that's why the project needs to get moving again :-)

Re:Reefknot (1)

walt-sjc (145127) | more than 11 years ago | (#5611742)

Looks like a dead project. There hasn't been an update to that site since fall of 2001, and Zero messages on the dev list in 2003 (99 in 2002, 1500 in 2001 for reference.)

Maybe someone can revive it.

Re:Reefknot (3, Informative)

babbage (61057) | more than 11 years ago | (#5612037)

Ignore what the online web archives say -- my reefknot folder has a full 25 messages from 2003 in there, and another fifty or so since I subscribed in Sept 2002, so the seem to be at least partially incomplete.

Moreover, I work with one of the core developers, and am pretty sure that she doesn't feel ReefKnot is dead, it's just hibernating :-)

There is interest in keeping the project going, but well work and all that nonsense has gotten in the way. If public momentum starts to build back up then things could start going again with the core developers (including any interested new ones).

I personally [not speaking for my employer yadda yadda yadda] would like to see more web sites start offering iCal feeds of some of the material they publish, such as listings for concerts, movies, and tv shows. If ReefKnot could evolve into something that could support that, I'd be happy to help out with the effort.

Nobody has written the server (4, Informative)

GOD_ALMIGHTY (17678) | more than 11 years ago | (#5611122)

The standards exist, but no one has written the server.
You can't really blame them since the Calendar Access Protocol (CAP) which is going to be the IMAP+SMTP of Calendaring, providing synchronous calendaring to clients is on it's 10th draft [] . Read this email [] if you have lost hope that the IETF would have calendaring anytime soon. Appearently draft 11 is coming soon and it will be the last one. So it looks like CAP will be finalized RSN. (Thank God, this thing was becoming like Duke Nukem Forever)

You could poke a stick at the OpenCap Server [] project and see if you get a response. But I haven't heard anything in months.

I don't know what's up with the Libical [] guys. The mail archive has been dead since December 16. Of course some of them are working on Free Association [] which is supposed to be a server and client. Since the mailing lists for libical seem dead I couldn't tell you what the status of CAP support currently is. My understanding was that they had been keeping up with the drafts, but since the 10th one was released about a month ago, I have no idea what the current status is.

Mozilla should be getting Calendaring in 1.4. IIRC, the calendaring uses libical. The College of Charleston computing dept has taken on enhancing the client (Go Cougars!). Hopefully they'll be putting CAP support in.

If anyone wants to know what it would take to write a calendar server and put an end to the Notes/Exchange duopoly in groupware, visit the Calendaring and Scheduling Working Group [] of the IETF. These are the guys that have brought you iCAL (RFC2445), iTIP (RFC2446), iMip (RFC2447), iCal Locating and LDAP (RFC2739) and the Guide to Internet Calendaring (RFC3283).

Read the iCalendar Guide then all the other documents at the site. Next go write the server. Then make sure Mozilla's Calendar client works with it, and email me so I can go replace exchange servers with it.

If you find a solution that does not use CAP, beat the authors with a ClueStick till they give in and write something that uses IETF protocols so we can interop with it.

Personally I'd really like to see the Cyrus IMAP [] server get a CAP piece put in. Combined with OpenLDAP [] and Mozilla as the client, it would be a Notes/Exchange killer.

While I'm sitting here making demands from the Open Source messaging community, why the hell doesn't Mozilla get SIEVE (RFC3028) support so we can have a standard for server-side email filtering rules, Cyrus supports it in the IMAP server. Oh, and I also want write support for LDAP address books in Mozilla.

To answer the original question, I think it's coming, slowly, but coming. Lord knows, I've only been waiting for 4 years or so.

Re:Nobody has written the server - YES! They did! (1, Informative)

Urgoll (364) | more than 11 years ago | (#5611774)

The standards exist, but no one has written the server.

Then take a look at Sun's Sun ONE Calendar Server. It's a new revision of a relatively old product (based on Netscape Calendar Server, but rewritten from scratch), aimed at complete IETF standard complience. It's based on CAP and iCalendar.

In addition, it has a web interface for universal access.

Oh, and I also want write support for LDAP address books in Mozilla.

Well, it's there I think. I use Mozilla 1.3, and in the address book there's the option to add an LDAP server. Granted, I haven't tested it yet, so it may not work.

Re:Nobody has written the server - YES! They did! (1)

GOD_ALMIGHTY (17678) | more than 11 years ago | (#5616050)

The Calendar Server from Sun doesn't support CAP. It has an interface for WCAP which is their "we need something now" attempt, but no clients support it. Sun's Calendar Server is almost as proprietary as Notes and Exchange as far as interfacing it.

There are several Calendaring/Groupware solutions that are purely web-based, but what happens when CAP clients appear? What if you need offline support or PDA synching? Also Sun's Calendar server is the only one that does synchronous calendaring, meaning it checks other schedules and allow you to pull in resources and people into meetings. None of the Open Source ones do this, they are based on iCal, iTip and iMip which only provide a way to publish individual calendars. There is no backend that can resolve conflicts or give a real-time availability to someone creating a new entry. Apple's solutiona and that Kroupware project for the German government are like this, they simply publish iCal files and have no conflict resolution.

In other words, if Sun's Calendar Server supported clients it might have a chance against Notes/Exchange. If the open-source ones were synchronous and supported clients they might have a chance.

Using LDAP address books in read mode has been in there for ages. I want to be able to update the LDAP server from Mozilla.

Re:Nobody has written the server (1)

Rick the Red (307103) | more than 11 years ago | (#5616787)

Can you please explain, or point me to an explanation: What's the difference between CAP and iCalendar? Are they competing or complementary? Thanks.

Re:Nobody has written the server (1)

GOD_ALMIGHTY (17678) | more than 11 years ago | (#5617658)

iCalendar is a format for publishing calendar information. It's a file format.
CAP is a wire protocal like IMAP that allows a Calendar client to talk to a Calendar server. Read the Guide to Internet Calendaring I linked to in my earlier post.

An example, a calendar client (CUA: Calendar User Agent) would connection to a calendar server (CS: Calendar Store). The CUA might request all information between two dates for user jdoe. This would be communicated via CAP to the CS. The CS would send the response as a CAP response that encapsulated the calender information in iCalendar format.


Re:Nobody has written the server (1)

Rick the Red (307103) | more than 11 years ago | (#5617974)

Yes, thanks!

When considering changes, I think it's good to... (0)

Anonymous Coward | more than 11 years ago | (#5611171)

...refer to the Official Slashdot Problem Solving Flowsheet [] .

It looks like you're at the top right now.

A great service (0)

Anonymous Coward | more than 11 years ago | (#5611286)

That I can vouch for is; we use them pretty extensively and they do a really good job.


Horde (IMP) is moving towards this... (4, Informative)

jhealy1024 (234388) | more than 11 years ago | (#5611418)

If the software were tied to an SQL backend, then you could even offer a web enabled front end, perhaps even with a tie in to projects like IMP.

The Horde Framework [] (of which IMP [] is a sub-project) has it's own web-enabled calendar. The project is called Kronolith [] , and it's moving towards what you need.

While not all of its features are complete, it looks to include support for shared calendars, the iCal standard, and ICAP support through MCAL [] (other posts have addressed ICAP and it's not-quite-settled status). Thus, when the dust has settled, it should interoperate with other calendars. In the meantime, it's web-based right now, so that might provide what you need before all the formats are finished.

Disclaimer: I am friends with members of the Horde dev team.

old /. discussion about reefknot (2, Informative)

BigBir3d (454486) | more than 11 years ago | (#5611590)

here []

UW Calendar (2, Informative)

A moron (37050) | more than 11 years ago | (#5611675)

I've been looking for something similiar for quite some time. The closest thing I've found so far is UW Calendar []

"The UW Calendar project is building an open-source calendaring system for higher education. UW Calendar will support personal, public and group events, use existing open standards, and support web-based and other forms of access, including uPortal integration."

ICS Files. (2, Informative)

lnoble (471291) | more than 11 years ago | (#5611708)

I've been very impressed with PHP iCalendar. It does quite well at parsing .ics files which can be created using iCal, the Mozilla Calendar, and KOrganizer among others. Of course it currently can't edit them, but that's an easily fixed problem.

Get it here:

How about Sun ONE Calendar Server ? (1)

Urgoll (364) | more than 11 years ago | (#5611729)

It's a commercial product, yes. But it seems to fit the requirements: It has a web-based interface for universal access, plus iCal or XML export, and it has a data exchange module with Palm desktop and Outlook.

More details here []

WebDAV and Apache! (2, Informative)

Glass of Water (537481) | more than 11 years ago | (#5611772)

iCalendar is a standard, as was mentioned above. You can have a calendar hosted on a web server using apache and mod_dav. O'Reilly [] has a good piece on it. [ ical_webdav.html]

Tiki? (2, Informative)

DamienMcKenna (181101) | more than 11 years ago | (#5611835)

Tiki 1.6 [] , currently under development and due for probably release within the next few weeks, is getting a calendaring system and they are looking at this being one of the few major features left to add. Maybe with some assistance (nudge, nudge) it could expand beyond the current goals into what you are discussing in the next version? Right now I'm finishing off adding LDAP support, and it already has webmail, NNTP, file and image galleries, wiki, weblog, and a really flexible permissions system.

Re:Tiki? (1)

Zarquon (1778) | more than 11 years ago | (#5612025)

Heh.. namespace overload. Tiki [] (also hosted by sourceforge) is the graphical frontend for the scientific software run on one of the Beowulf Clusters at Georgia Tech. (Emag simulations, to be precise).

Palm device integration? (2, Interesting)

ibennetch (521581) | more than 11 years ago | (#5612072)

How about adding something that would sync to a Palm device? This is probably quite a bit off-topic as the original question was regarding server-side solutions that could be accessed by any application. But I'm curious -- how hard would it be to integrate a calendar, stored online somewhere with the server the original poster is asking about, with a Palm device. I assume that the only hurdle would be finding a client programm that speaks both to the Palm and the server -- does such a thing exist? If not, why not?

There is a client independent Calendar (-1, Redundant)

Anonymous Coward | more than 11 years ago | (#5612178)

Sun makes a client independent calendar intergrated with LDAP. It's called Sun ONE Calendar Server. Uses the iCal standards to a fair degree and only needs a web browser with javascripting. Not open source, but at least it exists.

Liberal Arts School (1)

jkidd (552837) | more than 11 years ago | (#5618701)

How come these questions come from Liberal Arts Schools?? Cause all the technical people went to real schools.
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