Virtuoso Open-Source Edition

  • Topic
  • Discussion
    • VOS.VirtPubSubHub(Last) -- DAVWikiAdmin? , 2017-06-29 07:43:26 Edit
    [TXT]
    [PLAIN]
    [DOCBOOK]
    WebDAV System Administrator 2017-06-29 07:43:26

    Example of Linked Data Usage of PubSubHubbub Implementation

    The following example demonstrates how to use Virtuoso's implementation of the draft PubSubHubBub Protocol to handle Linked Data.

    We extend the idea of tracking a feed to track Linked Data resource URIs.

    To reveal the hub to subscribers, we propose Linked Data resources return the following HTTP header -- 

    Link: <http://cname/psh/subscribe.vsp>; rel="hub"

    -- or include the following in an HTML <head&/lt; (or similar) element -- 

    <link rel="hub" uri="http://cname/psh/subscribe.vsp">

    Endpoints

    The PubSubHubBub package installed on a system would define the following endpoints :

    http://cname/psh/subscribe.vsp subscription endpoint
    http://cname/psh/publish.vsp publishing endpoint
    http://cname/psh/ index to UI of the simple test clients
    http://cname/psh/callback.vsp default built-in client callback endpoint

    Example of use of the built-in demo client

    1. As a very first step we use a simple client to subscribe to a SIOC document containing data for an ODS-Weblog. In our tests we subscribe to the Linked Data document <http://ec2-174-129-156-25.compute-1.amazonaws.com/dataspace/demo/weblog/demo%27s%20Weblog/sioc.rdf>.



    2. The Weblog post is as follows:



    3. During the subscription process, the client will get the initial state of the SIOC feed, so we can execute the following query to see all post titles:



    4. In the query result is the title of the existing Weblog post:



    5. Next we add a new blog post to force a change to the SIOC data:



    6. Using a simple publishing UI, we notify the Hub the data has changed:



    7. The Hub takes the delta and notifies the subscribers:



    8. Again we execute the same SPARQL query as in the earlier step, and now we can see the data contains the new blog post title:



    Related