All, A new draft of the Feed Rank extension has been published. Andreas Sewe has joined on as an author and has contributed significantly to this rev of the draft. There are many updates to the extension that are worth highlighting.
http://www.ietf.org/internet-drafts/draft-snell-atompub-feed-index-09.txt First, the purpose of this extension is to provide a flexible means of ranking entries within a feed. For instance, a feed might represent an ordered listing of items from a movie rental queue; or each entry in a feed might contain a five star review ranking; or each entry in the feed might represent a listing of a students graded homework assignment, where each rank represents the grade assigned to the work, etc. For example, when combined with Mark Nottingham's Feed History extension for marking a feed as "complete", Feed Rank provides a good solution for representing a movie rental queue: <feed xmlns="http://www.w3.org/2005/Atom"; xmlns:r="http://purl.org/syndication/rank/1.0";> <id>tag:example.org,2006:my_movie_queue</id> <fh:complete xmlns:fh="http://purl.org/syndication/history/1.0"/> <title type="text">My Movie Queue</title> <updated>2006-05-01T12:00:00Z</updated> <author><name>James</name></author> <link rel="self" href="queue.xml" /> <link href="queue.html" /> <r:scheme name="tag:example.org,2006:my_movie_queue" label="Queue Position" significance="descending"> <r:range minimum="0" step="1" /> </r:scheme> <r:scheme name="tag:example.org,2006:movie_reviews" label="Customer Reviews" signifiance="ascending"> <r:range minimum="0.0" maximum="5.0" step="0.5" scale="1" /> </r:scheme> <entry> <id>tag:example.org,2006:movies/chaplin/citylights</id> <title type="text">City Lights</title> <updated>2006-05-01T12:00:00Z</updated> <link href="/movies/chaplin/citylights.html" /> <summary>Charlie Chaplin's cassic film</summary> <r:rank domain="" scheme="tag:example.org,2006:my_movie_queue">1</r:rank> <r:rank domain="tag:example.org,2006:movie_reviews" scheme="tag:example.org,2006:movie_reviews">4.5</r:rank> </entry> <entry> <id>tag:example.org,2006:movies/chaplin/moderntimes</id> <title type="text">Modern Times</title> <updated>2006-05-01T12:00:00Z</updated> <link href="/movies/chaplin/moderntimes.html" /> <summary>Another Chaplin classic</summary> <r:rank domain="" scheme="tag:example.org,2006:my_movie_queue">3</r:rank> <r:rank domain="tag:example.org,2006:movie_reviews" scheme="tag:example.org,2006:movie_reviews">3.5</r:rank> </entry> <entry> <id>tag:example.org,2006:movies/chaplin/thegoldrush</id> <title type="text">The Gold Rush</title> <updated>2006-05-01T12:00:00Z</updated> <link href="/movies/chaplin/thegoldrush.html" /> <summary>Chaplin in a frozen wilderness</summary> <r:rank domain="" scheme="tag:example.org,2006:my_movie_queue">2</r:rank> <r:rank domain="tag:example.org,2006:movie_reviews" scheme="tag:example.org,2006:movie_reviews">5.0</r:rank> </entry> </feed> While there are a variety of changes throughout the entire spec, the key differences in this draft lie in the definition of the Ranking Schemes. A Ranking Scheme is now defined as a set of discreet values and/or ranges. For instance, a typical U.S. grading scheme can be represented using a series of ranges representing percentage values: <r:scheme name="tag:example.org,2006:grades" label="Percentage Grading System" significance="ascending"> <r:range label="F" minimum="0.00" maximum="0.59" scale="2" step="0.01" /> <r:range label="D" minimum="0.60" maximum="0.69" scale="2" step="0.01" /> <r:range label="C" minimum="0.70" maximum="0.79" scale="2" step="0.01" /> <r:range label="B" minimum="0.80" maximum="0.89" scale="2" step="0.01" /> <r:range label="A" minimum="0.90" maximum="0.99" scale="2" step="0.01" /> <r:value label="A+" scale="2">1.00</r:value> </r:scheme> In contrast, the typical German grading scheme can be represented as a set of discreet values: <r:scheme name="tag:example.org,2006:grades" label="Grading System" significance="descending"> <r:value label="1" scale="1">1.0</r:value> <r:value label="1-" scale="1">1.3</r:value> <r:value label="2+" scale="1">1.7</r:value> <r:value label="2" scale="1">2.0</r:value> <r:value label="2-" scale="1">2.3</r:value> <r:value label="3+" scale="1">2.7</r:value> <r:value label="3" scale="1">3.0</r:value> <r:value label="3-" scale="1">3.3</r:value> <r:value label="4+" scale="1">3.7</r:value> <r:value label="4" scale="1">4.0</r:value> <r:value label="4-" scale="1">4.3</r:value> <r:value label="5+" scale="1">4.7</r:value> <r:value label="5" scale="1">5.0</r:value> <r:value label="5-" scale="1">5.3</r:value> <r:value label="6+" scale="1">5.7</r:value> <r:value label="6" scale="1">6.0</r:value> </r:scheme> Anyway, as always, feedback is welcomed and requested. - James
