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109 lines
4.5 KiB
109 lines
4.5 KiB
<html xmlns="http://www.w3.org/1999/xhtml">
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<head>
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<meta name="generator" content=
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"HTML Tidy for Mac OS X (vers 31 October 2006 - Apple Inc. build 13), see www.w3.org" />
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<title>
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What do HTTP URIs Identify? - Design Issues
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</title>
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<link rel="Stylesheet" href="di.css" type="text/css" />
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<meta http-equiv="Content-Type" content=
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"text/html; charset=us-ascii" />
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</head>
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<body bgcolor="#DDFFDD" text="#000000" xml:lang="en" lang="en">
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<address>
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Tim Berners-Lee<br />
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Date: 2005-06-09, last change: $Date: 2006/10/29 17:19:39
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$<br />
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Status: personal view only. Editing status: first draft. This
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was written when the W3C Technical Architecture group
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responded TAG issue HTTPRange-14. This resolves the question
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originally addressed in a previous <em><a href=
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"HTTP-URI.html">What to HTTP URIs Identify</a></em> note.
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</address>
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<p>
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<a href="./">Up to Design Issues</a>
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</p>
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<hr />
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<h1>
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What HTTP URIs Identify
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</h1>
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<h2>
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<a name="Abstract" id="Abstract">Abstract</a>
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</h2>
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<p>
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HTTP URIs, in the web architecture, have been used to denote
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documents -- "web pages" informally, or "information
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resources" more formally. However, with the growth of the
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Semantic Web, which uses URIs to denote anything at all, the
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urge to use and practice of using HTTP URIs for arbitrary
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things grew steadily. The W3C Technical Architecture group
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eventually decided to resolve the architectural problem that
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if an HTTP response code of 200 (a successful retrieval) was
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given, that indicated that the URI indeed was for an
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information resource, but with no such response, or with a
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different code, no such assumption could be made. This
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compromise resolved the issue, leaving a consistent
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architecture.
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</p>
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<h2 id="Introducti">
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Introduction
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</h2>
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<p>
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HTTP URIs, in the web architecture, have been used to denote
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documents -- "web pages" informally, or "information
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resources" more formally. However, with the growth of the
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Semantic Web, which uses URIs to denote anything at all, the
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urge to use and practice of using HTTP URIs for arbitrary
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things grew steadily. The Dublin Core project, one of the
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first RDF vocabularies, and later Friend of a Friend, and
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various others simply used HTTP URIs to identify RDF
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Properties. The result was that one could no longer be sure
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that an HTTP URI was intended to identify the web page one
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got when one used the URI in a browser. In fact, there was a
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danger of confusion is one party used the URI for an abstract
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concept and another used it for the web page. The author
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wrote a long <em>Design Issues</em> note about this, <a href=
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"HTTP-URI.html">What do HTTP URIs Identify?</a>. The reader
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is directed to read that if more detail of the arguments is
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needed.
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</p>
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<p>
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This whole issue caused, until 2005, a lot of discussion in
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technical circles, and much heated debate. In June 2005, the
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TAG resolved the issue as a function of the runtime protocol
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response. Basically, the argument is that if you have used a
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URI to get a web page, then you can use the URI to identify
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the Information Resource which is that web page: For example,
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the New York Times home page, or this page you are reading
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now.
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</p>
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<h3 id="Resolution">
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Resolution
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</h3>
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<p>
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The TAG resolution effectively extends the range of things
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one can use HTTP URIs. However, it does not allow one to
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simply serve a web page at a URI which is used for something
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else. Of course, it is a general principle of web
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architecture that it is useful to serve information to those
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that look up a URI. In the case that the URI is not intended
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to be used for an information resource.
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</p>
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<p>
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The W3C Technical Architecture group eventually decided to
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resolve the architectural problem that if an HTTP response
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code of 200 (a successful retrieval) was given, that
|
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indicated that the URI indeed was for an information
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resource, but with no such response, or with a different
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code, no such assumption could be made. This compromise
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resolved the issue, leaving a consistent architecture.
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</p>
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<hr />
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<p>
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<a href="Overview.html">Up to Design Issues</a>
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</p>
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<p>
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<a href="../People/Berners-Lee">Tim BL</a>
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</p>
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</body>
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</html>
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