Progressive loading of XML pages is loading and simultaneously displaying already loaded and processed parts of an XML page while the XSLT template is still processing the rest of the parts.
We have a very large XML. This is an article with a lot of comments. On a slow and unstable mobile Internet, you might not wait for it to load. During the download, the connection is broken and the XML remains not loaded. It would seem that you can just refresh the page and the browser would just load the missing part. But no. The browser loads the page again and again it fails and we see an error instead of the page.
But there is a way out of this situation. We will split the XML into small pieces that will have time to load on a slow channel and get into the cache. As a bonus, we get underload protection and progressive loading.
What will we work with
XML article
This file contains a title, description, article text and many, many comments. More precisely, there are 5962 comments.
Each comment has an 'index' attribute. This index is used by other comments in the 'on' attribute to indicate that the comment is a reply to the comment whose index is specified.
lorem-ipsum.xml
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet href=".xslt" type="text/xsl"?>
<>
<title xmlns="http://www.w3.org/1999/xhtml">Lorem Ipsum</title>
<meta name="description" content="Neque porro quisquam est qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit..." xmlns="http://www.w3.org/1999/xhtml"/>
<>Quisque sollicitudin malesuada urna, id tincidunt quam. Pellentesque luctus, sem vel posuere efficitur, est enim pulvinar orci, et vulputate orci dui a libero. Nam eget mauris sed diam pretium fermentum. Proin euismod ultrices justo, non aliquet ipsum bibendum at. Duis eget laoreet mauris. Morbi tristique arcu libero, quis pharetra justo bibendum eget. In at quam sed lacus vestibulum tincidunt quis ut ex.</>
< ="1">
Nunc sit amet ligula mauris. Integer vel nisi ac turpis rhoncus suscipit. Fusce elementum ut elit quis rutrum. Nulla bibendum placerat ex pulvinar accumsan. Praesent vestibulum hendrerit accumsan. Sed quis ligula pretium, condimentum enim in, cursus elit. Phasellus quis mauris arcu. Integer congue ex et ante porttitor vestibulum. Donec vel mauris venenatis, ultrices leo in, dapibus metus. Morbi pharetra eleifend libero nec efficitur. Fusce efficitur et ligula quis scelerisque. Curabitur eget nibh at nunc lacinia fringilla et eget quam. Praesent malesuada, odio in pulvinar semper, libero nunc consectetur lorem, vel egestas erat tellus nec ipsum.
</>
<!-- ... -->
< ="1" ="4">
Praesent varius vitae arcu sed imperdiet. Proin pulvinar a augue blandit scelerisque. Pellentesque lectus erat, gravida lobortis lorem ut, dignissim tempor felis. Nunc porttitor libero quis est sodales, non ornare metus eleifend. Cras orci lacus, auctor non sollicitudin lacinia, ultricies vitae diam. Fusce eu leo varius, interdum sapien ac, vestibulum orci. Sed placerat feugiat odio, vitae tempor tellus volutpat tincidunt. Cras dapibus est et mi euismod ornare. Vestibulum accumsan justo non volutpat dictum. Curabitur porttitor, magna id euismod tincidunt, metus nisl fermentum tellus, id pulvinar leo nibh vel velit. Sed gravida gravida sapien et porttitor. Nam volutpat, ex id faucibus commodo, arcu arcu fringilla mi, et volutpat nunc turpis at ligula. Pellentesque et vulputate ligula, lobortis dignissim ligula. Nulla laoreet auctor ultricies. Interdum et malesuada fames ac ante ipsum primis in faucibus.
</>
<!-- ... -->
</>Basic XSLT Template
This is a small XSLT template that transforms XML into full-fledged xHTML and gathers comment threads from a list.
article.xslt
<xsl:stylesheet
version="1.0"
xmlns="http://www.w3.org/1999/xhtml"
xmlns:x="http://www.w3.org/1999/xhtml"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" indent="yes" encoding="UTF-8"/>
<!-- -->
<xsl:key name="" match="" use="@"/>
<!-- -->
<xsl:template match="node()|@*">
<xsl:copy>
<xsl:apply-templates select="node()|@*" />
</xsl:copy>
</xsl:template>
<!-- xHTML -->
<xsl:template match="">
<html>
<head>
<!-- xHTML title meta -->
<!-- -->
<xsl:copy-of select="x:title | x:meta[@name = 'description']"/>
<style>
. {
padding: 1vw;
min-width: 20em;
border: 1px solid gray;
color: black;
background-color: white;
}
. {
max-width: 46em;
margin: auto;
text-align: justify;
}
</style>
</head>
<body>
<!-- ( )-->
<xsl:apply-templates select="@*" />
<div class="">
<!-- 'title' -->
<h1><xsl:value-of select="x:title"/></h1>
<!-- 'content' 'meta' -->
<i><xsl:value-of select="x:meta[@name = 'description']/@content"/></i>
<!-- '' -->
<p><xsl:apply-templates select="/node()" /></p>
</div>
<!-- -->
<xsl:apply-templates select="." mode=""/>
</body>
</html>
</xsl:template>
<!-- -->
<xsl:template match="" mode="">
<details id="" open=''>
<summary></summary>
<!-- @ -->
<xsl:apply-templates select="[not(@)]"/>
</details>
</xsl:template>
<!-- -->
<xsl:template match="">
<!-- "" -->
<div class="" id="{@}">
<!-- -->
<xsl:apply-templates select="@*" />
<!-- -->
<a href="#{@}"><xsl:value-of select="@"/></a><xsl:text>: </xsl:text>
<div class="">
<!-- -->
<xsl:apply-templates select="node()" />
</div>
<!-- -->
<xsl:apply-templates select="." mode=""/>
</div>
</xsl:template>
<!-- -->
<xsl:template match="" mode="">
<!-- -->
<xsl:if test="key('', @)">
<details open=''>
<summary></summary>
<!-- -->
<xsl:apply-templates select="key('', @)"/>
</details>
</xsl:if>
</xsl:template>
</xsl:stylesheet>Testing
GPRS. . , , XML XSLT .
: 10,77
XML
.
.
XML , XSLT .
XML '-', XML , .
xslt\--.xslt:
<xsl:stylesheet
version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" encoding="UTF-8"/>
<xsl:key name="" match="" use="@"/>
<!-- -->
<xsl:param name="" />
<!-- -->
<xsl:template match="node()|@*">
<xsl:copy>
<xsl:apply-templates select="node()|@*" />
</xsl:copy>
</xsl:template>
<!-- -->
<xsl:template match="">
<!-- -->
<xsl:param name="-" select="floor(@ div $)" />
<!-- -->
<xsl:param name="-" select="key('', @)[floor(@ div $) > $-]"/>
<!-- -->
<xsl:copy>
<!-- "" "" -->
<xsl:apply-templates select="@*" />
<!-- -->
<xsl:if test="$-">
<!-- "-" -->
<xsl:attribute name="-">
<!-- -->
<xsl:call-template name="-">
<!-- -->
<xsl:with-param name="" select="$-" />
</xsl:call-template>
</xsl:attribute>
</xsl:if>
<!-- -->
<xsl:apply-templates select="node()" />
</xsl:copy>
</xsl:template>
<xsl:template name="-">
<!-- -->
<xsl:param name=""/>
<!-- -->
<xsl:param name="-" select="floor($[1]/@ div $)"/>
<!-- -->
<xsl:param name="-" select="$[floor(@ div $) > $-]"/>
<!-- -->
<xsl:value-of select="$-"/>
<!-- -->
<xsl:if test="$-">
<!-- -->
<xsl:text> </xsl:text>
<!-- -->
<xsl:call-template name="-">
<!-- -->
<xsl:with-param name="" select="$-" />
</xsl:call-template>
</xsl:if>
</xsl:template>
</xsl:stylesheet>XML
.
xslt\--.xslt:
<xsl:stylesheet
version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<!-- 'method' 'text' -->
<xsl:output method="text" encoding="UTF-8"/>
<!-- XML -->
<xsl:param name="" select="100" />
<xsl:template match="/">
<!-- XML -->
<xsl:value-of select="floor(count(//) div $)"/>
</xsl:template>
</xsl:stylesheet>('') XML .
xslt\-.xslt:
<xsl:stylesheet
version="1.0"
xmlns:x="http://www.w3.org/1999/xhtml"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" encoding="UTF-8"/>
<xsl:param name="" />
<!-- -->
<xsl:param name=""/>
<!-- -->
<xsl:param name=""/>
<xsl:template match="/">
<!-- -->
<xsl:processing-instruction name="xml-stylesheet">href="../-.xslt" type="text/xsl"</xsl:processing-instruction>
<!-- -->
<xsl:apply-templates select="" />
</xsl:template>
<xsl:template match="">
< ="{$}">
<!-- title meta -->
<xsl:copy-of select="x:title | x:meta[@name = 'description']"/>
<!-- -->
<xsl:copy-of select="[floor(@ div $) = $]" />
</>
</xsl:template>
</xsl:stylesheet>, .
xslt\-.xslt:
<xsl:stylesheet
version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" encoding="UTF-8"/>
<!-- -->
<xsl:template match="node()|@*">
<xsl:copy>
<xsl:apply-templates select="node()|@*" />
</xsl:copy>
</xsl:template>
<xsl:template match="/">
<!-- -->
<xsl:processing-instruction name="xml-stylesheet">href="../-.xslt" type="text/xsl"</xsl:processing-instruction>
<!-- -->
<xsl:apply-templates select="" />
</xsl:template>
<!-- -->
<xsl:template match=""/>
</xsl:stylesheet>msxsl.exe
msxsl.exe. XML XSLT stdout .
CMD
XML .
progressive.cmd lorem-ipsum.xml 100
progressive.cmd:
chcp 65001
rem XML
md "%~dpn1"
rem
msxsl.exe %1 "%~dp0xslt\--.xslt" -xw -o "%~dpn1\index.xml" =%2
rem XML
for /f "delims=" %%a in ('msxsl.exe %1 ^"%~dp0xslt\--.xslt^" ^=%2') do set =%%a
rem
for /l %%i in (0,1,%%) do msxsl.exe -o "%~dpn1\%%i.xml" "%~dpn1\index.xml" "%~dp0xslt\-.xslt" =%2 =%%i ="%~n1"
rem
msxsl.exe "%~dpn1\index.xml" "%~dp0xslt\-.xslt" -o "%~dpn1\index.xml". . .
-.xslt
<xsl:stylesheet
version="1.0"
xmlns="http://www.w3.org/1999/xhtml"
xmlns:x="http://www.w3.org/1999/xhtml"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" indent="yes" encoding="UTF-8"/>
<!-- ".xslt" -->
<xsl:include href="%D1%81%D1%82%D0%B0%D1%82%D1%8C%D1%8F.xslt"/>
<xsl:template match="" mode="">
<!-- -->
<iframe style="display:none;" id="-" src="0.xml"/>
<script><![CDATA[
setTimeout(function(){
var = document.querySelector("#-");
if ( && .contentDocument)
{
var = .contentDocument.getElementById('');
//
if ()
{
//
document.body.appendChild();
return;
}
}
// Timeout
setTimeout(arguments.callee, 100);
}, 100)]]>
</script>
<noscript>
<!-- JavaScript -->
<a href="0.xml"></a>
</noscript>
</xsl:template>
</xsl:stylesheet>XML .
-.xslt
<xsl:stylesheet
version="1.0"
xmlns="http://www.w3.org/1999/xhtml"
xmlns:x="http://www.w3.org/1999/xhtml"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="html" indent="yes" encoding="UTF-8"/>
<!-- ".xslt" -->
<xsl:include href="%D1%81%D1%82%D0%B0%D1%82%D1%8C%D1%8F.xslt"/>
<!-- -->
<xsl:key name="" match="" use="@"/>
<xsl:param name="" select="/@"/>
<xsl:template match="/">
<!-- ".xslt" -->
<xsl:apply-templates select="document(concat($, '/index.xml'))/"/>
</xsl:template>
<!-- -->
<xsl:template match="" mode="">
<details id="" open=''>
<!-- -->
<summary></summary>
<!-- -->
<xsl:call-template name="-"/>
</details>
</xsl:template>
<xsl:template name="-">
<!-- XML 0 -->
<xsl:param name="" select="0"/>
<!-- XML -->
<xsl:param name="" select="document(concat($, '/', $, '.xml'))"/>
<!-- XML -->
<xsl:if test="$">
<!-- -->
<xsl:apply-templates select="$//[not(@)]" />
<!-- XML -->
<xsl:call-template name="-">
<!-- XML -->
<xsl:with-param name="" select="$ + 1" />
</xsl:call-template>
</xsl:if>
</xsl:template>
<!-- -->
<xsl:template match="" mode="">
<!-- XML -->
<xsl:if test="key('', @) or @-">
<details open=''>
<summary></summary>
<!-- XML -->
<xsl:apply-templates select="key('', @)"/>
<!-- XML -->
<xsl:call-template name="-"/>
</details>
</xsl:if>
</xsl:template>
<xsl:template name="-">
<!-- -->
<xsl:param name="" select="concat(@-, ' ')"/>
<!-- -->
<xsl:param name="" select="substring-before($, ' ')"/>
<!-- -->
<xsl:if test="$">
<!-- XML -->
<xsl:apply-templates select="document(concat($, '/', $, '.xml'))" mode="">
<!-- -->
<xsl:with-param name="" select="@"/>
</xsl:apply-templates>
<!-- -->
<xsl:call-template name="-">
<!-- -->
<xsl:with-param name="" select="substring-after($, ' ')"/>
</xsl:call-template>
</xsl:if>
</xsl:template>
<xsl:template match="/" mode="">
<!-- -->
<xsl:param name=""/>
<!-- -->
<xsl:apply-templates select="key('', $)"/>
</xsl:template>
</xsl:stylesheet>Turn on the GPRS speed limit in the browser and start the page load.
Loading article text: 2.28s
Loading first comments: 14.41s (only in FireFox)
Full load: 11.33 minutes