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HBX RSS Protocol Support

Revision as of 16:30, 7 September 2006 by (Talk | contribs)

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The Higgins extension has support for the RSS-P protocol. RSS-P is a specific way to use RSS 2.0 (well, the SSE extensions to RSS 2.0) to allow an external site to synchronize the state of its profile data with the profile data managed by a web service called the Higgins i-card broker, or broker for short.

The broker makes available an RSS-P feed to the external site. Using this feed the site receives updates to the user's profile data. Since we are using the SSE extensions to RSS, only the deltas (the incremental changes) are transmitted. The external site can also make available an RSS-P feed of its own to allow the broker to subscribe to updates made by the site. Both the broker and the site consume these RSS-P feeds and merge the updates they contain into their current profile state. In this way the two states are kept synchronized.

Higgins extension processing

Using a browser equipped with the Higgins extension (aka HBX), the Higgins extension looks for an <object> tag of type "application/rss-p", within an enclosing form tag. Here is a generic example:

   <form name="rss-p-test" method="post" action="url-of-action-page">
     <object type="application/rss-p" name="RSS-P">
       <param name="schema" value="url-of-owl-schema"/>
       <param name="feedURL" value=""/>


  • the url-of-action-page is the page to which the RSS feed will be posted
  • the value of schema (url-of-owl-schema) is the URL location of an owl file that describes the set of properties that the site desires
  • the value of feedURL is the URL location of the site's RSS feed containing changes to the user's profile information as maintained by the site.

WARNING: You must not include testhostname param that you may have noticed in the HTML of the Higgins server's test pages. This is only for debugging. The effect of testhostname is to override the true value of host name above to the value of the testhostname param tag.

The RSS-P feed at feedURL

There is an important constraint on the name of the site's RSS-P feed. The feed must have the same name as the user ID of the broker's RSS feed the first time that the Higgins extension lands on a site page containing the <form> construct described above.

For example, consider a broker whose user id is "dedab43-7851-417c-9558-32bc8b28f050". If this user's browser + Higgins extension lands on a site page with RSS-P <form> and <object> tags, the site will receive the following HTTP POST notification (without the linebreak after the "="!):

Assuming that "" was the value of the form's action attribute. As you can see, the user's id is appended with a trailing ".xml" to create the name of the broker's feed for the site to read. When the broker needs to synchronize user's information with the site it will merge its user's profile data with the contents of the feed at:

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