Testing Cocoon (Apache: The Definitive Guide, 3rd Edition)

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19.6. Testing Cocoon

While the Cocoon examples are a welcome way to see that the installation process has gone smoothly, you'll most likely want to get your own documents into the system. Unlike the other application-building tools covered in the last few chapters, most uses of Cocoon start with publishing information rather than interacting with users. The following demonstration provides a first step toward publishing your own information, though you'll need a book on XSLT to learn how to make the most of this.

We'll start with a simple XML document containing a test phrase:

<?xml version="1.0"?>
<phrase>
 testing, testing, 1... 2... 3...
</phrase>

Save this as test.xml in the main Cocoon directory. Next, we'll need an XSLT stylesheet, stored as test2html.xsl in the main Cocoon directory, to transform that "phrase" document into an HTML document:

<?xml version="1.0"?>
<xsl:stylesheet version="1.0"
     xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

<xsl:template match="phrase">
 <html>
  <head><title><xsl:value-of select="." /></title></head>
  <body><h1><xsl:value-of select="." /></h1></body>
 </html>
</xsl:template>

</xsl:stylesheet>

This stylesheet creates an HTML document when it encounters the phrase element and uses the contents of the phrase element (referenced by <xsl:value-of select="." />, which returns the contents of the current context) to fill in the title of the HTML document, as well as a header in body content. What appeared once in the XML document will appear twice in the HTML result.

We now have the pieces that Cocoon can use to generate HTML, but we still need to tell Cocoon that these parts have a purpose. Cocoon uses a site map, stored in the XML file sitemap.xmap, to manage all of its processing. Processing is defined using pipelines, which can be sophisticated combinations of stylesheets and code, but which in our case need to provide a home for an XML document and its XSLT transformation. By adding one map:pipeline element to the end of the map:pipelines element, we can add our test to the list of pipelines Cocoon will run.

  <map:pipeline>
    <map:match pattern="test" />
    <map:generate src="test.xml" />
    <map:transform src="test2html.xsl" />
    <map:serialize />
  </map:pipeline>

This pipeline will match any requests to "test" that Cocoon receives, which means that we'll see the results at http://localhost/cocoon/test. It will take the test.xml document, transform it using the test2html.xsl document, and then serialize the document for delivery using its standard HTML serializer. Once you save this file, Cocoon will be ready to display our test — there's no need to restart Cocoon, Tomcat, or Apache.

Visiting http://localhost/cocoon/test with a browser shows off the result of the transformation. A close look at the source code reveals that Cocoon has been at work, and its HTML serializer even added some metacontent:

<html><head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>testing, 
testing, 1... 2... 3...</title></head>
<body>
<h1>
 testing, testing, 1... 2... 3...
</h1>
</body></html>

This is a very small taste of Cocoon's capabilities, but this foundation demonstrates that you can use Cocoon in conjunction with Tomcat Apache without having to make many changes to your Apache installation.