[http://creativecommons.org/licenses/by/3.0/]
This work is licensed under a CC
Attribution 3.0 Unported License [http://creativecommons.org/licenses/by/3.0/]
The Web's architecture has very simple principles revolving around the ideas of placing a heavy emphasis on a consistent and global identification mechanism for resources, a standardized way of how resource representations can be retrieved, and a standardized way of how resource representations should be usable by using standardized media types. This lecture presents an overview of these architectural principles and illustrates them with using blogs as an example of Web-based applications.
Summary [http://www.w3.org/TR/webarch/summary.html] of Ian Jacobs, Norman Walsh,Architecture of the World Wide Web, Volume One, World Wide Web Consortium, Recommendation REC-webarch-20041215, December 2004 [http://www.w3.org/TR/webarch/]
There are two ways of constructing a software design: One way is to make it so simple that there are obviously no deficiencies, and the other way is to make it so complicated that there are no obvious deficiencies. The first method is far more difficult.
C. A. R. Hoare [http://en.wikipedia.org/wiki/Charles_Antony_Richard_Hoare], The Emperor's Old Clothes
, 1980 Turing Award Lecture [http://dret.net/biblio/reference/hoa81]
Web Technologiesare not integrated into the Web
Web Applicationsare not integrated into the Web
The ideal Webvs.
the real Web
<?xml version="1.0" encoding="UTF-8"?> <blogxml> <post date="2006-05-25"> <title>Holyrood Park</title> <text>Located in the middle of Edinburgh, Holyrood Park is a hill with a lot of rock and grass.</text> <image src="holyrood-park">View from the west with the most spectacular cliffs.</image> </post> <post date="2007-05-15"> <title>Half Dome</title> <text>The trip to half dome is a long one, but very beautiful and with a spectacular final climb.</text> <image src="half-dome">Me on top of half dome.</image> </post> <post date="2007-05-20"> <title>Fifth Lake</title> <text>The seven lakes loop offers views of (surprise!) seven lakes settled in a remote valley.</text> <image src="fifth-lake">Still a lot of ice on fifth lake.</image> </post> <post date="2007-05-22"> <title>Golden Canyon</title> <text>Golden Canyon leads to the famous Zabriskie Point overlook.</text> <image src="golden-canyon">A maze of erosion patterns carved in sediment.</image> </post> <post date="2007-08-12"> <title>Red Rock Canyon</title> <text>Red Rock Canyon is easily reachable from Las Vegas and has some nice trails.</text> <image src="red-rock-canyon">Red Rock Canyon is called Red Rock Canyon for a reason.</image> </post> </blogxml>
<xsl:for-each select="distinct-values( for $i in //post/@date return substring($i, 1, 4) )">
<xsl:result-document href="dretblog/{current()}/index.html">
<html>
<head><xsl:sequence select="dret:head(format-date(xs:date(concat(current(), '-01-01')), '[Y]'), '../')"/></head>
<body>
<h1><a href="..">dretblog</a></h1>
<h2><xsl:value-of select="format-date(xs:date(concat(current(), '-01-01')), '[Y]')"/></h2>
<xsl:for-each select="$stdin//post[starts-with(@date, current())]">
<p><a href="../{translate(@date, '-', '/')}/{dret:postname(title)}"><xsl:value-of select="concat(format-date(@date, '[F] [MNn] [D], [Y]'), ': ', title)"/></a></p>
</xsl:for-each>
</body>
</html>
</xsl:result-document>
</xsl:for-each> <xsl:for-each select="distinct-values( for $i in //post/@date return substring($i, 1, 7) )">
<xsl:result-document href="dretblog/{translate(current(), '-', '/')}/index.html">
<html>
<head><xsl:sequence select="dret:head(format-date(xs:date(concat(current(), '-01')), '[MNn] [Y]'), '../../')"/></head>
<body>
<h1><a href="../..">dretblog</a></h1>
<h2>
<xsl:value-of select="format-date(xs:date(concat(current(), '-01')), '[MNn] ')"/>
<a href="../.."><xsl:value-of select="format-date(xs:date(concat(current(), '-01')), '[Y]')"/></a>
</h2>
<xsl:for-each select="$stdin//post[starts-with(@date, current())]">
<p><a href="../../{translate(@date, '-', '/')}/{dret:postname(title)}"><xsl:value-of select="concat(format-date(@date, '[F] [MNn] [D], [Y]'), ': ', title)"/></a></p>
</xsl:for-each>
</body>
</html>
</xsl:result-document>
</xsl:for-each> <xsl:for-each select="distinct-values(//post/@date)">
<xsl:result-document href="dretblog/{translate(current(), '-', '/')}/index.html">
<html>
<head><xsl:sequence select="dret:head(format-date(xs:date(current()), '[F] [MNn] [D], [Y]'), '../../../')"/></head>
<body>
<h1><a href="../../..">dretblog</a></h1>
<h2>
<xsl:value-of select="format-date(xs:date(current()), '[F] ')"/>
<a href=".."><xsl:value-of select="format-date(xs:date(current()), '[MNn]')"/></a>
<xsl:value-of select="format-date(xs:date(current()), ' [D], ')"/>
<a href="../.."><xsl:value-of select="format-date(xs:date(current()), '[Y]')"/></a>
</h2>
<xsl:for-each select="$stdin//post[starts-with(@date, current())]">
<p><a href="../../../{translate(@date, '-', '/')}/{dret:postname(title)}"><xsl:value-of select="concat(format-date(@date, '[F] [MNn] [D], [Y]'), ': ', title)"/></a></p>
</xsl:for-each>
</body>
</html>
</xsl:result-document>
</xsl:for-each> <body>
<h1><xsl:value-of select="title"/></h1>
<h2>
<a href="./"><xsl:value-of select="format-date(@date, '[F]')"/></a>
<xsl:text> </xsl:text>
<a href=".."><xsl:value-of select="format-date(@date, '[MNn]')"/></a>
<xsl:text> </xsl:text>
<a href="./"><xsl:value-of select="format-date(@date, '[D]')"/></a>
<xsl:text>, </xsl:text>
<a href="../.."><xsl:value-of select="format-date(@date, '[Y]')"/></a>
</h2>
<a href="../../../../../img/{image/@src}.jpg" title="{image}"><img src="../../../../../img/{image/@src}-small.jpg"/></a>
<p><xsl:value-of select="text"/></p>
</body> <feed xmlns="http://www.w3.org/2005/Atom" xml:base="http://dret.net/lectures/web-fall09/src/dretblog.atom">
<title>dretblog</title>
<id>http://dret.net/lectures/web-fall09/src/dretblog.atom</id>
<link rel="self" href=""/>
<updated><xsl:value-of select="current-dateTime()"/></updated>
<author><name>Erik Wilde</name></author>
<xsl:for-each select="//post">
<entry xml:base="http://dret.net/lectures/web-fall09/src/{translate(@date, '-', '/')}/{dret:postname(title)}">
<title><xsl:value-of select="title"/></title>
<link href="http://dret.net/lectures/web-fall09/src/{translate(@date, '-', '/')}/{dret:postname(title)}"/>
<id><xsl:value-of select="concat('http://dret.net/lectures/web-fall09/src/', translate(@date, '-', '/'), '/', dret:postname(title))"/></id>
<published><xsl:value-of select="@date"/>T00:00:00Z</published>
<updated><xsl:value-of select="current-dateTime()"/></updated>
<content type="xhtml">
<div xmlns="http://www.w3.org/1999/xhtml">
<h1><xsl:value-of select="title"/></h1>
<h2><xsl:value-of select="format-date(@date, '[F] [MNn] [D], [Y]')"/></h2>
<a href="http://dret.net/lectures/web-fall09/img/{image/@src}.jpg" title="{image}"><img src="http://dret.net/lectures/web-fall09/img/{image/@src}-small.jpg"/></a>
<p><xsl:value-of select="text"/></p>
</div>
</content>
</entry>
</xsl:for-each>
</feed><feed xmlns="http://www.w3.org/2005/Atom" xml:base="http://dret.net/lectures/web-fall09/src/dretblog.atom">
<title>dretblog</title>
<id>http://dret.net/lectures/web-fall09/src/dretblog.atom</id>
<link rel="self" href=""/>
<updated>2007-08-30T00:52:27.718-07:00</updated>
<author>
<name>Erik Wilde</name>
</author>
<entry xml:base="http://dret.net/lectures/web-fall09/src/2006/05/25/holyrood_park">
<title>Holyrood Park</title>
<link href="http://dret.net/lectures/web-fall09/src/2006/05/25/holyrood_park"/>
<id>http://dret.net/lectures/web-fall09/src/2006/05/25/holyrood_park</id>
<published>2006-05-25T00:00:00Z</published>
<updated>2007-08-30T00:52:27.718-07:00</updated>
<content type="xhtml">
<div xmlns="http://www.w3.org/1999/xhtml">
<h1>Holyrood Park</h1>
<h2>Thursday May 25, 2006</h2>
<a href="http://dret.net/lectures/web-fall09/img/holyrood-park.jpg" title="View from the west with the most spectacular cliffs.">
<img src="http://dret.net/lectures/web-fall09/img/holyrood-park-small.jpg"/>
</a>
<p>Located in the middle of Edinburgh, Holyrood Park is a hill with a lot of rock and grass.</p>
</div>
</content>
</entry>