Re: [syndication] RSS suitable for date/time relative material ?

[Mark Nottingham <mnot@mnot.net>]

Don't know if you're aware of these or not, but just in case - 

IETF Calendaring and Scheduling WG:
  http://www.ietf.org/html.charters/calsch-charter.html

W3C RDF Calendar Interest Group list: 
  http://lists.w3.org/Archives/Public/www-rdf-calendar/2001Apr/0000.html

  The focus of the list is on practical implementation work
  (testbeds, prototypes, collaborative development), although
  theoretical work (eg. on representations for events, time-periods
                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  etc) in RDF, XML, DAML etc.

I'm interested in solutions like the sy namespace below, for a
variety of applications (HTTP freshness, P3P policy expiration, etc.)
Did that come from somewhere particular (I didn't see a reference)?

Cheers,


On Sat, Apr 14, 2001 at 07:17:33PM -0700, Simon Fell wrote:
> Rael, thanks for the info, I finally got some time to work on this
> (much later than planned), I have a question about sy:updateBase,
> should this be kept upto date (i.e. the last time the rss was
> generated), or can it be a static value that is used to work out the
> schedule ?
> 
> i.e. i have
>   <sy:updatePeriod>hourly</sy:updatePeriod>
>   <sy:updateFrequency>3</sy:updateFrequency>
>   <sy:updateBase>2001-01-01T01:10:00Z</sy:updateBase>
> 
> To indicate that the channel is updated 3 times an hour at 10, 30 & 50
> minutes past the hour.
> 
> I decided in the end to go with a mix of dc:date and a textual
> description of the date (see [1] if you want to see a full sample)
> 
> I also decided to split the data into two separate rss files, one for
> upcoming events, and one that details newly archived events, does this
> make sense (i was having a hard time working out how to do this in a
> single file)
> 
> If all goes well, this should go live early next week, i'll post the
> real URL's when it does.
> 
> Thanks
> Simon
> 
> [1] http://www.4s4c.com/sf/test_live.rss
> 
> On Mon, 12 Mar 2001 00:34:46 -0800, in soap you wrote:
> 
> >Howdy,
> >
> >RSS is perfect for your purposes.  Unfortunately you're right, 0.9x do not
> >currently have a per-item date/time element.  It's exactly the problems
> >you're encountering (overloading existing title or description elements)
> >that led to RSS 1.0's modular extensibility.
> >
> >RSS 1.0[1] allows you to either supply such information using one of the
> >existing modules (Dublin Core[2] seems apropos) or via your own ad hoc
> >modular extension.
> >
> >You could:
> >
> >  a) Use the Dublin Core "date" element to represent the date
> >     of publication or broadcast; there's no restriction against
> >     this date being in the future[3].
> >
> >     <dc:date>2001-01-01T12:00+00:00</dc:date>
> >
> >     (That's January 1st, 2001 at 12:00 noon GMT.)
> >
> >or
> >
> >  b) Create your own ad-hoc extension(s), something like this:
> >
> >     <broadcast:date>2001-01-01</broadcast:date>
> >     <broadcast:time>12:00</broadcast:time>
> >
> >     if that suits you better.
> >
> >     The "broadcast" prefix would be associated with a URI representing
> >     a namespace for this modular extension thusly:
> >
> >     xmlns:broadcast="http://me.org/rss/mod_broadcast";
> >
> >Of course it'd probably be far more useful to make use of a more standard
> >extension whenever possible so as to aid interoperability with those
> >applications not specifically designed to make use of your ad hoc
> >extensions.  Any RSS application understanding and using dc:date would have
> >no trouble with a) above.
> >
> >As an aside, Dave Winer has asked before (can't quite remember where,
> >unfortunately) whether or not 0.92[4] should include a date/time element at
> >the item level; I'd say so -- I keep seeing it popping up in postings like
> >this one and it would also perhaps work nicely with the <enclosure> element
> >so as to allow enclosures to be scheduled for some time in the future while
> >the URL is already known.
> >
> >Regards,
> >
> >Rael
> >
> >[1] http://purl.org/rss/1.0/
> >[2] http://purl.org/rss/1.0/modules/dc/
> >[3] "A date associated with an event in the life cycle of the resource"
> >    http://purl.org/dc/elements/1.1/
> >[4] http://backend.userland.com/rss092
> 
> 
>  
> 
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ 
> 
> 

-- 
Mark Nottingham
http://www.mnot.net/