- From: Mark Nottingham <mnot@akamai.com>
- Date: Tue, 17 Apr 2001 15:54:09 -0700
- To: Alan Davies <aland@steltor.com>
- Cc: Carl Benkley <cbenkley@mitre.org>, www-rdf-calendar@w3.org
Very much so, thanks! I'm always in favour of modular standards docs, and it looks like there might be considerable value in having a spin-off here. BTW, another recent one is: http://www.ietf.org/internet-drafts/draft-ietf-impp-datetime-00.txt Yet another choice... Cheers, On Tue, Apr 17, 2001 at 05:04:50PM -0400, Alan Davies wrote: > Here's some info from the calsch group, I had assumed that > one of our more eager posters would have provided you with a > full response earlier... > > iCalendar has a RECUR value type, which can express > quite complex (arguably too complex) recurrences > using units ranging from seconds to years (including days of > the week, month, year, etc.), for example "every Sunday in > January at 8:30 AM and 9:30 AM, every other year": > > RRULE:FREQ=YEARLY;INTERVAL=2;BYMONTH=1;BYDAY=SU;BYHOUR=8,9;BYMINUTE=30 > > iCalendar also a PERIOD value type, used for durations. > For more information- http://ietf.org/rfc/rfc2445.txt 4.3.9 and > 4.3.10 > > If you prefer XML syntax, there is a draft (which unfortunately > wasn't renewed, so has expired- I can send you a copy if you like) > that proposes an iCalendar DTD. > > One thing to note is that a simplification of the recurrence rules > has been recently suggested, as another WG (iptel) wanted to use > the iCalendar syntax, but needed to be able to test whether a given > date intersected with a rule in a time linear with the length of the > rule. See http://ietf.org/internet-drafts/draft-ietf-iptel-cpl-04.txt > 5.3 and Appendix A. Some posts related to this issue: > http://www.imc.org/ietf-calendar/mail-archive/msg06890.html > http://www.imc.org/ietf-calendar/mail-archive/msg06979.html > > hope this is of some use... > > --Alan > > > At 16:03 2001-04-17 -0400, Carl Benkley wrote: > >Mark, > > > >Your question may be quick, but I doubt there is any quick answer. What > >you are looking for is a general way of expressing first occurence plus > >recurring interval (and possibly last occurence) My first guess would be > >to model it with the full range of possibilities that the data types in > >XML Schemas would allow. A couple of valid possibilities within this > >context are "dateTime" plus "duration" (duration treated as a recurring > >interval), and "date" plus "gDay". Unfortunately, the folks that > >brought us XML Schemas and the Gregorian ("g") date datatypes didn't > >give us a day-of-the-week, which seems critical to what you want to do. > >You could of course make up a dayOfWeek datatype. > > > >Also, I'm wondering if you are concerned only with events that happen in > >an instant of time. Modeling events of non-zero duration obviously > >requires some way of modeling that duration. > > > >Carl Benkley > >Lead Information Systems Engineer > >MITRE Corporation > > > > > >Mark Nottingham wrote: > > > > > > Hello, > > > > > > I sent the attached message to the IETF calsch WG a few days ago, and > > > haven't gotten anything back. Does anyone here have strong feelings > > > about this, and/or a reference? > > > > > > I'd like to see something moving towards a (hopefully short) standard > > > here, as there are a number of different application domains. Or > > > perhaps I'm just missing one that already exists (crosses fingers)? > > > > > > Cheers, > > > > > > -- > > > Mark Nottingham, Research Scientist > > > Akamai Technologies (San Mateo, CA USA) > > > > > > ------------------------------------------------------------------------ > > > > > > Subject: representing scheduled events > > > Date: Sun, 15 Apr 2001 14:01:49 -0700 > > > From: Mark Nottingham <mnot@akamai.com> > > > To: ietf-calendar@imc.org > > > > > > Hello, > > > > > > Just a quick question. I've seen several fields where it's desireable > > > to model a scheduled event and then represent it in some form (XML or > > > a simple string, usually). > > > > > > For example, I'd want to model and express: > > > - "Every Tueday at 6pm" > > > - "The first Monday of the month at noon" > > > - "Every other day at midnight" > > > > > > Possible uses include for HTTP cache freshness, recurring events in > > > RSS news feeds, and policy updates for things like P3P. In general, > > > I'm talking about representing a publication schedule. > > > > > > Does calsch have a solution for this, or any thoughts that would > > > point an effort to develop such a thing in the right direction? > > > > > > Cheers, > > > > > > -- > > > Mark Nottingham, Research Scientist > > > Akamai Technologies (San Mateo, CA USA) -- Mark Nottingham, Research Scientist Akamai Technologies (San Mateo, CA USA)
Received on Tuesday, 17 April 2001 18:54:51 UTC