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Re: Proposal: Web Federation Protocol

From: Dominique Guardiola <dguardiola@quinode.fr>
Date: Mon, 2 Jul 2012 13:49:55 +0200
Message-Id: <1FCDC649-C8F6-4AA2-8A4D-9307CED2E89D@quinode.fr>
To: public-rww@w3.org

Le 2 juil. 2012 à 13:22, Kingsley Idehen a écrit :

>> I wonder if it would be possible to apply Pubsubhubbub to Linked Data.
>> By that I mean that a subscriber to a Linked Data document would receive updates with actual changes to that document, rather than simply being notified that "something has changed" .
> 
> Yes, that's been implemented for a while [1].
> 
> 1. http://apassant.net/2010/04/18/sparql-pubsubhubbub-sparqlpush/ -- sparqlPUSH

We're working our own adaptation of PubSubHubbub for Linked data
SPARQL PuSH was the model, but we ended doing something simpler, closer to PuSH 0.3 spec :

- the feeds are generated by a web application, not directly tied to a SPARQL endpoint, so we have generic feeds for resources of each RDF Classes, and more complex feeds corresponding to SPARQL queries, containing different types of resources.
- the feed entries URL are the objects URIs
- the "summary" payload in the atom feed is a JSON-LD serialized version of the object (yes, JSON in XML ...)

we could also only use the feed to push dereferenceable URIs, but as it required one more connection, we thought it'd be ok to push the last state of the resource directly in the feed.
Then sites subscribe to classic PuSH feeds and then create or update the RDF objects they receive via the feed.
Each site runs its own private hub for publications and subscriptions, so the whole thing is truely distributed

I don't know if a new federation protocol is worth the effort
But bridging the gap between linked data and pubsubhubbub is definitely easy

There's some new work happening right now on the future PubSubhubbub 0.4 spec:
http://blog.superfeedr.com/pubsubhubbub-0-4/
https://superfeedr-misc.s3.amazonaws.com/pubsubhubbub-core-0.4.html



--
Dominique Guardiola, QUINODE
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Received on Monday, 2 July 2012 11:50:24 GMT

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