Re: [Tzdist] Fwd: [tzdist] #32 (service): managing historical data

[Lester Caine <[e-mail]>]

On 10/12/14 19:22, Cyrus Daboo wrote:
> Hi Lester,
> 
> --On December 10, 2014 at 7:17:13 PM +0000 Lester Caine
> <[e-mail]> wrote:
> 
>> When I publish a diary of events I have to add the name of the publisher
>> of the TZ data I've used along with the version of data. That is then
>> fixed and anybody accessing the diary can also access the TZ data used
>> to create it. If one of the archive services freezes a copy of the pages
>> then when ever they are looked at the user knows what data is needed to
>> view it. If a user has a copy of the diary cached locally, and then
>> finds that the 'latest' TZ version has changed they can easily assess if
>> it affects anything they are looking at.
> 
> No! I don't want to send an event to attendees with a tzid that is fixed
> to a particular publisher or version, because otherwise, when the
> version changes and my client starts using the new version, I will have
> to re-send the event invitation with the new version detail to all the
> attendees (and I may have 1000's of events with 1000's of attendees) -
> that is exactly what we don't want to do (and exactly what happens today
> with iCalendar clients that are currently required to send the VTIMEZONE
> data in their invites). The current process is arguably broken - nearly
> all iCalendar clients throw away the VTIMEZONE data they receive from
> outside sources if the TZID matches one they already have locally. What
> we want to ensure is that clients can continue to do that and be able to
> rely on the fact that their local data is in sync with everyone else.

Cyrus ... I rest my case!

*I* want a single publisher and a single set of TZid's and I will be
using backzoneTZ to provide that data. But other users will probably not
have backzone so we have a broken system already. *YOU* will publish
events using your own publisher but your clients will have to use the
correct publisher to get the matching TZid's and data! Ideally these
will exactly match my data, but that is out of scope for the charter :(

If the details of an event change because someone has decided that what
was published is now wrong, then how do you identify the problem? Your
example is the exact explanation of the current problem, but how is your
current draft actually preventing the problem from happening? The event
invitation has to be updated to reflect the agreed change, but if I am
looking at the old version, and I see that there has been a variation
for this particular TZid then at least I know to ask.

-- 
Lester Caine - G8HFL
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