Web resource: Difference between revisions

Revision as of 21:08, 2 February 2023

Revision as of 19:31, 12 May 2023

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===Using HTTP URIs to identify abstract resources===

[[URL]]s, particularly [[uniform resource identifier|HTTP URI]]s, are frequently used to identify abstract resources, such as classes, properties or other kind of concepts. Examples can be found in RDFS or OWL [[Ontology (computer science)|ontologies]]. Since such URIs are associated with the HTTP protocol, the question arose of which kind of representation, if any, should one get for such resources through this protocol, typically using a web browser, and if the syntax of the URI itself could help to differentiate "abstract" resources from "information" resources. The URI specifications such as RFC 3986 left to the protocol specification the task of defining actions performed on the resources and they don'tdo not provide any answer to this question. It had been suggested that an HTTP URI identifying a resource in the original sense, such as a file, document, or any kind of so-called information resource, should be "slash" URIs — in other words, should not contain a [[fragment identifier]], whereas a URI used to identify a concept or abstract resource should be a "hash" URI using a fragment identifier.

For example: <code><nowiki>http://www.example.org/catalogue/widgets.html</nowiki></code> would both identify and locate a web page (maybe providing some human-readable description of the widgets sold by Silly Widgets, Inc.) whereas <code><nowiki>http://www.example.org/ontology#Widget</nowiki></code> would identify the abstract concept or class "Widget" in this company ontology, and would not necessarily retrieve any physical resource through [[HTTP protocol]]. But it has been answered that such a distinction is impossible to enforce in practice, and famous standard vocabularies provide counter-examples widely used. For example, the [[Dublin Core]] concepts such as "title", "publisher", "creator" are identified by "slash" URIs like <code><nowiki>http://purl.org/dc/elements/1.1/title</nowiki></code>.