[saga-rg] Timestamp issue

[Mark Mc Keown]

Hi Andre

> Wow!  you are thorough! :-)  Thanks!

Unfortuntely I wasn't thorough enough, I didn't include
xsd:DateTime which is what much of the underlying middleware
will be using.

For a description of the issues related to timestamps and
standards check out the following thread on the Atom mailing 
list:

http://www.imc.org/atom-syntax/mail-archive/msg13103.html

I think the solution that the Atom people came up with
is a good compromise as it is complient with xsd:DateTime,
ISO 8601, RFC 3339 and the W3C profile of ISO 8601:

>>>

3.3.  Date Constructs

   A Date construct is an element whose content MUST conform to the
   "date-time" production in [RFC3339].  In addition, an uppercase "T"
   character MUST be used to separate date and time, and an uppercase
   "Z" character MUST be present in the absence of a numeric time zone
   offset.

   atomDateConstruct =
      atomCommonAttributes,
      xsd:dateTime

   Such date values happen to be compatible with the following
   specifications: [ISO.8601.1988], [W3C.NOTE-datetime-19980827], and
   [W3C.REC-xmlschema-2-20041028].

   Example Date constructs:

   <updated>2003-12-13T18:30:02Z</updated>
   <updated>2003-12-13T18:30:02.25Z</updated>
   <updated>2003-12-13T18:30:02+01:00</updated>
   <updated>2003-12-13T18:30:02.25+01:00</updated>

   Date values SHOULD be as accurate as possible.  For example, it would
   be generally inappropriate for a publishing system to apply the same
   timestamp to several entries that were published during the course of
   a single day.

<<<

The above is from RFC 4287, http://www.ietf.org/rfc/rfc4287.txt

I am not fully clued up on what SAGA is doing but you could include
a helper function that would convert the above DateTime into seconds 
from the epoch. 

cheers
Mark




> 
> Seems that w3 has a similar convention as the ISO standard
> Chris referred to.  
> 
> Well, what was that famous quote again: "The nice thing
> about standards is that there are so many to choose from"
> ;-)
> 
> Do you, or Chris, or others, have any opinion which version
> we should use?
> 
> I personally think that the ISO and W3 one are not looking
> particularily beautiful, with T (!) as a delimiter, but they
> are surely simple enough to parse...
> 
> On the other we try to stay close to POSIX in many places,
> so sticking with ctime, or even seconds since epoch, would
> also be well justified...
> 
> Cheers, Andre.
> 
> 
> 
> Quoting [Mark.McKeown at manchester.ac.uk] (May 17 2006):
> > 
> > The W3C has a profile of ISO 8601 which simplifies life:
> > 
> > http://www.w3.org/TR/NOTE-datetime
> > 
> > Also IETF have a RFC "Date and Time on the
> > Internet: Timestamps":
> > 
> > http://www.faqs.org/rfcs/rfc3339.html
> > 
> > Other Relevent standards that specify dates are:
> > 
> > RFC 822 and RFC 1123
> > 
> > The HTTP protocol accepts dates in a number of formats,
> > from section 3.3.1:
> > 
> > "HTTP applications have historically allowed three different formats
> >  for the representation of date/time stamps:
> > 
> >       Sun, 06 Nov 1994 08:49:37 GMT  ; RFC 822, updated by RFC 1123
> >       Sunday, 06-Nov-94 08:49:37 GMT ; RFC 850, obsoleted by RFC 1036
> >       Sun Nov  6 08:49:37 1994       ; ANSI C's asctime() format"
> > 
> > 
> > Hope this helps
> > Mark
> > 
> > >
> > >>Quoting [Christopher Smith] (May 05 2006):
> > >>>
> > >>>Does anybody have a pointer to the relevant ISO standard?
> > >>
> > >>Is there an ISO standard for that?
> > >>
> > >I found this link:
> > >
> > >http://www.iso.org/iso/en/prods-services/popstds/datesandtime.html
> > >
> > >but I haven't read it in any detail.
> > >
> > >-- Chris
> > >
> > >
> > >
> 
> 
> 
>