[Cosmo] Re: [Dev] Ozzie on Calendaring

[Alec Flett]

Mitchell Kapor wrote:
> Lisa (Dusseault) and I spoke to Ray at When 2.0 about SSE. 
>
> SSE is defined at the level of abstract item replication; it's not a 
> network access protocol and is mute on those issues.  That is, it 
> addresses how to replicate an RSS feed to have two or more instances 
> which are kept in sync with each other.
Jeffrey and I both read over the microsoft spec on SSE after I posted 
about it... its a pretty good idea but, as you said, it leaves a lot of 
work up to the client.

Surprisingly, it seems like a pretty good solution for a sort of 
peer-to-peer network over http, if you imagine that a running chandler 
with an HTTP server could publish an RSS feed of a shared calendar, poll 
other RSS feeds for the same calendar, and publish back the user's 
changes in the hope that other clients would be polling it... The only 
problem being that peer-to-peer over HTTP is just nasty, with firewalls, 
changing IP addresses, and the like.

But it got me thinking anyway and possible solutions to try and leverage 
the idea, but in a way that would work better for peer-to-peer.. (for 
chandler 2.0 maybe :))

1) Allow chandler to publish to an external HTTP server over WebDAV, 
sftp, ftp, etc. (e.g. in my life I would make chandler publish to 
flett.org. In a university setting, I might post it to a common 
university-run web server. As a client, chandler would still be polling 
peer web sites.
2) RSS-over-jabber - instead of polling an http server, just subscribe 
to remote jabber clients and they could push out their RSS changes.

And of course, none of these three options (these last two plus the 
original idea of serving up RSS feeds directly from a running chandler 
over http) are exclusive of each other.

Alec


>   It detects conflicts but leaves it entirely up to the client to 
> decide what to do.  Typically, SSE would be implemented by publishing 
> a feed to a server and handling subscriptions to that feed but in 
> theory there could be P2P implementations.  SSE permits feeds to have 
> multiple writers, so the terms "publish" and "subscribe" are a bit 
> misleading.  SSE adds unique ID's for items to RSS feeds.
>
> Because SSE was meant for different Microsoft applications and 
> services  such as Outlook and MSN to share calendar items, it has been 
> assumed that each app would deal with all of the messy implementation 
> details not defined in SSE itself.  SSE itself is incomplete as a 
> standard and doesn't address issues of what happens if two clients are 
> trying to write to the feed simultaneously, for instance.  So for SSE 
> to be a useful public standard, these aspects would have to use  an 
> existing standard or borrow from one.
>
> It would certainly be possible for a WebDAV server to be used to 
> support SSE with a modest amount of work.  Since RSS support is  in 
> the queue for Cosmo, it makes sense for us to follow SSE development 
> carefully, and consider adding support if it looks like SSE is gaining 
> momentum outside Microsoft.
>
> Apologies for any lack of technical precision.  I'm sure Lisa can 
> amplify and correct as needed.
>
>
>
> On Dec 8, 2005, at 8:59 AM, Alec Flett wrote:
>
>>
>> I ran into this yesterday, thought it even more interesting than 
>> coverage of ourselves:
>> http://news.com.com/1606-2-5984715.html
>>
>> Anyone know anything about this RSS+SSE for publishing and syncing 
>> calendars?
>>
>> http://msdn.microsoft.com/xml/rss/sse/
>>
>> Yeah yeah, its microsoft, but it seems like its something we can't 
>> ignore...
>>
>> Alec
>>
>> Philippe Bossut wrote:
>>> In the (very) unlikely event some of you haven't seen it, there's a 
>>> quite extensive video coverage of this conference (held yesterday at 
>>> Stanford) on CNEt with words from Mitch on Chandler... :)
>>>    http://news.com.com/1606-2-5985814.html
>>>
>>> Cheers,
>>> - Philippe
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