Re: [Tzdist] tzdist examples

[Cyrus Daboo <[e-mail]>]

Hi Lester,

--On January 11, 2015 at 10:08:20 PM +0000 Lester Caine 
<[e-mail]> wrote:

> I don't see any problem - as far as I am aware as long as the hash
> returned via ETag for the same data package is the same for each server
> then there is no problem

That may not happen. Remember that each server takes the raw publisher data 
and generates a representation in the media formats it servers up. For 
iCalendar, the generated data is not guaranteed to be byte-for-byte the 
same across all servers because different iCalendar libraries may generate 
data in slightly different ways, or generate different values for required 
properties like the product id.

We need to separate ETags (which represent a byte-for-byte state token for 
an HTTP resource) from the "semantic" state token - which in the case of 
tzdist is the tuple (publisher, version).

The (publisher, version) tuple is what clients use to sync across different 
servers - the ETag is what clients use to update from a server it already 
has data for. That is covered in the examples I sent out - in particular #3 
which shows a client with existing data from one server, trying to sync 
with a different server. I believe that covers exactly what you are after.

-- 
Cyrus Daboo