VirtPubSubHubExample of Linked Data Usage of PubSubHubbub ImplementationExample 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 : <tgroup><thead /><tbody> <row><entry> http://cname/psh/subscribe.vsp </entry><entry> subscription endpoint </entry></row> <row><entry> http://cname/psh/publish.vsp </entry><entry> publishing endpoint </entry></row> <row><entry> http://cname/psh/ </entry><entry> index to UI of the simple test clients </entry></row> <row><entry> http://cname/psh/callback.vsp </entry><entry> default built-in client callback endpoint </entry></row> </tbody></tgroup></table> <bridgehead class="http://www.w3.org/1999/xhtml:h2"> Example of use of the built-in demo client</bridgehead> <orderedlist spacing="compact"><listitem>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 <<ulink url="http://ec2-174-129-156-25.compute-1.amazonaws.com/dataspace/demo/weblog/demo%27s%20Weblog/sioc.rdf">http://ec2-174-129-156-25.compute-1.amazonaws.com/dataspace/demo/weblog/demo%27s%20Weblog/sioc.rdf</ulink>>. <figure><graphic fileref="VirtPubSubHub/step1.png" /></figure> </listitem> <listitem>The Weblog post is as follows: <figure><graphic fileref="VirtPubSubHub/step2.png" /></figure> </listitem> <listitem>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: <figure><graphic fileref="VirtPubSubHub/step3.png" /></figure> </listitem> <listitem>In the query result is the title of the existing Weblog post: <figure><graphic fileref="VirtPubSubHub/step4.png" /></figure> </listitem> <listitem>Next we add a new blog post to force a change to the SIOC data: <figure><graphic fileref="VirtPubSubHub/step5.png" /></figure> </listitem> <listitem>Using a simple publishing UI, we notify the Hub the data has changed: <figure><graphic fileref="VirtPubSubHub/step6.png" /></figure> </listitem> <listitem>The Hub takes the delta and notifies the subscribers: <figure><graphic fileref="VirtPubSubHub/step7.png" /></figure> </listitem> <listitem>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: <figure><graphic fileref="VirtPubSubHub/step8.png" /></figure></listitem> </orderedlist><bridgehead class="http://www.w3.org/1999/xhtml:h2">Related</bridgehead> <itemizedlist mark="bullet" spacing="compact"><listitem><ulink url="VirtODSPubSubHub">Setting up PubSubHub in ODS</ulink> </listitem> <listitem><ulink url="VirtFeedPubSubHub">Feed subscription via PubSubHub protocol Example</ulink> </listitem> <listitem><ulink url="VirtPubSubHubACL">Setting Up PubSubHub to use WebID Protocol or IP based control lists</ulink> </listitem> <listitem><ulink url="http://virtuoso.openlinksw.com/dataspace/dav/wiki/Main/VirtGraphReplication">Virtuoso Graph Replication Guide</ulink> </listitem> <listitem><ulink url="http://virtuoso.openlinksw.com/dataspace/dav/wiki/Main/VirtSPARQLSSL">Creating and Using a SPARQL-SSL based Endpoint</ulink> </listitem> <listitem><ulink url="http://virtuoso.openlinksw.com/dataspace/dav/wiki/Main/VirtAuthServerUI">Set WebID Protocol ACLs using the Virtuoso Authentication Server UI</ulink> </listitem> <listitem><ulink url="http://virtuoso.openlinksw.com/dataspace/dav/wiki/Main/VirtAuthFOAFSSLACL">WebID Protocol ACLs Tutorial</ulink> </listitem> <listitem><ulink url="http://virtuoso.openlinksw.com/dataspace/dav/wiki/Main/VirtOAuthSPARQL">SPARQL OAuth Tutorial</ulink> </listitem> <listitem><ulink url="VirtODSFOAFSSL">WebID Protocol Support in OpenLink Data Spaces</ulink> </listitem> <listitem><ulink url="ODSPkiSetup">Guide to Setting up a X.509 certificate issuer and HTTPS listener and Generating ODS user certificates</ulink> </listitem> <listitem><ulink url="OdsKeyImport">CA Keys Import using Conductor</ulink> </listitem> <listitem><ulink url="ODSGenerateX509Certificate">Generate an X.509 Certificate hosted WebID Guide</ulink> </listitem> <listitem><ulink url="ODSBriefcaseFOAFSSLShareFile">ODS Briefcase WebID Protocol Share File Guide</ulink> </listitem> <listitem><ulink url="http://esw.w3.org/topic/foaf+ssl">WebID Protocol Specification</ulink> </listitem> <listitem><ulink url="https://foaf.me/simpleLogin.php">Test WebID Protocol Certificate page</ulink> </listitem> <listitem><ulink url="http://test.foafssl.org/cert/">WebID Protocol Certificate Generation page</ulink> </listitem> <listitem><ulink url="https://demo.openlinksw.com/sparql-ssl">Virtuoso Demo SPARQL-SSL Endpoint</ulink></listitem> </itemizedlist></section></docbook>