index.docbook

<article xmlns="http://docbook.org/ns/docbook" xmlns:xl="http://www.w3.org/1999/xlink" version="5.0"><title>Hello World App</title>

<section><title>Introduction</title>

<para>This is a simple introductory application demonstrating how view templates are associated with RDF resources.</para>

<orderedlist>
	<listitem><simpara>Access the Home Folder my clicking the main menu in the upper right and selecting "Home folder"</simpara></listitem>
	<listitem><simpara>From there, select the red "Create" dropdown and choose "Folder".</simpara></listitem>
	<listitem><simpara>Name your folder and click "Create".</simpara></listitem>
	<listitem><simpara>Click the main menu and select "Import folder contents"</simpara></listitem>
	<listitem><simpara>Click "Choose files" and select the Hello World Callimachus ARchive (CAR) - <link xl:href="http://callimachus.googlecode.com/files/helloworld.car">helloworld.car</link>.</simpara></listitem>
</orderedlist>

</section><section><title>Details</title>

<para><emphasis>helloworld.html</emphasis> is a simple HTML file. HTML files are served with no pre-processing on the part of Callimachus. This means that no additional HTML, CSS, or JavaScript is added. One can see the contents of <link xl:href="helloworld.html"><emphasis>helloworld.html</emphasis></link> immediately by clicking on it from the folder view. An HTTP request for <emphasis>helloworld.html</emphasis> (to the full URL, e.g. http://localhost:8080/helloworld/helloworld.html) will result in Callimachus serving the file verbatim. <emphasis>helloworld.html</emphasis> contains:</para>

<programlisting>
&lt;html&gt;
    &lt;body&gt;
        &lt;p&gt;Hello, World from HTML!&lt;/p&gt;
    &lt;/body&gt;
&lt;/html&gt;</programlisting>

<para>That's useful, but not so interesting. Now let's see how Callimachus processes requests for other resources. The <link xl:href="HelloClass">HelloClass</link> is a Callimachus Class with an associated view template of <link xl:href="helloworld.xhtml"><emphasis>helloworld.xhtml</emphasis></link>. Note the extension here is Xhtml, not plain html.</para>

<para><link xl:href="helloworld.ttl"><emphasis>helloworld.ttl</emphasis></link> is an RDF file in Turtle syntax. See the following URL for information about the Turtle format:</para>

<para><link xl:href="http://www.w3.org/TeamSubmission/turtle/">http://www.w3.org/TeamSubmission/turtle/</link></para>

<para><emphasis>helloworld.ttl</emphasis> tells Callimachus that the resource <emphasis role="strong">hello+resource</emphasis> is an instance of HelloClass. The <emphasis>helloworld.ttl</emphasis> file contains the following statements.</para>

<programlisting>
@prefix calli:&lt;http://callimachusproject.org/rdf/2009/framework#&gt;.
@prefix rdfs:&lt;http://www.w3.org/2000/01/rdf-schema#&gt;.

# Create a resource with a label
&lt;hello+resource&gt; a &lt;HelloClass&gt;
    ; rdfs:label "hello, resource"
.</programlisting>

<para><emphasis>helloworld.xhtml</emphasis> is nearly identical in content to <emphasis>helloworld.html</emphasis>. The difference is that <emphasis>helloworld.xhtml</emphasis> is serialized as XHTML, associated with a class and passes through the Callimachus evaluation process prior to being served - because it is being used as a view template to another resource (in this case, the HelloWorld class). helloworld.xhtml contains:</para>

<programlisting>
&lt;?xml version="1.0" encoding="UTF-8" ?&gt;
&lt;html xmlns="http://www.w3.org/1999/xhtml"&gt;
&lt;head&gt;
    &lt;title&gt;Hello, World!&lt;/title&gt;
&lt;/head&gt;
&lt;body resource="?this"&gt;
    &lt;div class="container"&gt;
        &lt;p&gt;{rdfs:label} from XHTML Template!&lt;/p&gt;
    &lt;/div&gt;
&lt;/body&gt;
&lt;/html&gt;
</programlisting>

<para>An HTTP request for <link xl:href="hello+resource">hello+resource</link> (to the full URL, e.g. http://localhost:8080/helloworld/hello+resource) will result in Callimachus looking at its RDF to determine if that resource is associated with a class that uses a view template. Seeing that it is, Callimachus will serve the file using the template <emphasis>helloworld.xhtml</emphasis> and you should see "Hello, resource from XHTML Template!" in your Web client.</para>

<para>Notice here how by viewing this data via the HelloClass view template (<emphasis>helloworld.xhtml</emphasis>), Callimachus replaced the string "{rdfs:label}" with the actual value of the {rdfs:label} property from the data! In this way we can use one template to display information about many diferent resources. </para>

<para>Try creating own class and view template and associate your own resources to your class. Remember that you can make your HTML look pretty simply by adding a CSS stylesheet reference to it.</para>
</section></article>