[Cosmo-dev] Re: [Design] Next service migration details

[Ted Leung]

On Dec 14, 2006, at 4:29 PM, Brian Moseley wrote:

> (replying to cosmo-dev instead of design)

Tough to figure out what the best venue for this discussion is, since  
it impacts Chandler and the service as well...   In any case...

>
> On 12/14/06, Jared Rhine <jared at wordzoo.com> wrote:
>> Could we review some of the account/migration/legacy aspects of  
>> the next
>> service migration?
>
> we made some decisions on this today, so i'll summarize them now
> instead of next week.
>
>> So, when when Cosmo 0.6 is pushed to osaf.us, what will users of
>> Chandler need to have in the account dialog?
>>
>> Will the Chandler account dialog look different?  I don't think any
>> changes are planned, but the semantics of say, the "path" will  
>> change;
>> will people need to change their clients?
>
> there was some thought of needing to change the path for existing
> cosmo sharing accounts. the reason is that the preview versions of
> chandler and cosmo will use a new sharing protocol (morse code) rather
> than dav, which they use today, and the url for publishing collections
> to the server will be different with this new protocol than with dav.
>
> a couple relevant points:
>
> * dav path in 0.6 will look like /cosmo/dav/<username> rather than
> /cosmo/home/<username>
>
> * in order to isolate chandler from any future url scheme changes on
> the cosmo end, and to provide an entry point for any application to
> find all the relevant information it needs about how to access a
> user's data via any of the protocols cosmo supports, we're introducing
> a new cosmo service that will return an xml document listing every url
> that can be used to accessed a user's info.
>
> the first thought was to put the new "user service document" (USD) at
> the path /cosmo/user/<username> .. but here's an idea - let's put the
> USD at /cosmo/home/<username>. that keeps existing chandler users from
> having to change anything about their sharing account configuration at
> all. chandler just needs to detect that it has never downloaded the
> USD for the user, go get it, and use it to find the new sharing urls
> for existing shared collections.

Could we put it in both locations so that we can eventually  
deprecate /cosmo/home/<username>?

>
>> If changes are needed, what's our backwards compatibility story?   
>> Will
>> all existing users need to update their account settings on the  
>> day the
>> service is updated?
>
> not if we do the above, nor will they need to re-share their
> collections. the upgrade should be seamless.
>
>> How about other Cosmo uses?  I believe the ATOM feed URL will be
>> changing, without support for previous URLs.  Will any Cosmo feed  
>> users
>> have their feeds break on the day the service is updated to Cosmo  
>> 0.6?
>
> yes - the feed url for a collection is changing in 0.6. we can either
> ask people to resubscribe to their collection feeds or we can put in
> some amount of backwards compatibility logic to continue supporting
> the old (but deprecated) url form. 'm moderately in favor of the
> former, but i'm willing to be convinced otherwise. thoughts?

What about returning 301 for the feeds moving?  Most good readers  
handle 301 correctly....