http://www.example.org/stuff … However, there followed a drift in the use of RSS as pure metadata about a resource to becoming a delivery mechanism for the resource itself. In other words, RSS got content. This gave the item something of a split personality, as demonstrated in this snippet of RSS 1.0:
http://www.example.org/two Here is an item.This is an item … By its unambiguous RDF/XML interpretation, the item the description property refers to is the resource identified in the rdf:about attribute. But what does it mean for the resource also to have a (different)
URI? What is the relationship between the content here and the identified resource? The most Web architecture friendly interpretation would probably be that the inline content is a representation of the (rdf:about) identified resource, which may have other representations you can get over HTTP using the first URI. In these terms it s probably safest to think of the
as being a related resource. But the true interpretation only matters if people treat the material that way. The grassroots development of syndication has generally meant a shiny new feature stands a much better chance of adoption than any amount of theoretical spec-compliance. GUID Item identification became a problem for the simple XML-style formats because there was no reliable way of telling whether two items were the same. The result was that an item that had been published and later edited again could show up twice in newsreaders. This may sound obvious, but RSS 0.9x items already had fairly distinguishing features such as their title and pubDate (when the item was published). Except that pubDate was the official publication date, rather than any more dependable fixed point in time. The title could be changed at any time. So a new element was introduced: . Here is an example of how it might appear in a feed: http://example.org/three.html The optional isPermaLink attribute is an http: scheme URI that can be used to get a HTML representation of the item. Its default value is true, so most of the time the value of the element is equivalent to the RSS 1.0 rdf:about identifier. There is a caveat the isPermaLink value might be false and the text of the element may not be a URI at all, it can be any string that the source of the feed has established as unique. Crisis, What Crisis? The bottom line is that the RSS formats are pragmatic solutions to the problems that were around when the specs were authored, much of which related to the behavior of existing aggregator tools. One of the aims of Atom is to sort out such muddles and build on what are considered best practices in terms of the overall architecture of the Web. However, Atom is also constrained by the real-world demands of developers. So although existing specifications are followed closely, and ambiguity avoided wherever possible, there is bound to be some degree of improvising to make things work in the fairly messy environment of the Web. 255 Modeling Feed Data Note: In case you are looking for affordable and reliable webhost to host and run your j2ee application check Vision J2ee Web Hosting services.
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