Creating a Planet Me Blog Aggregator

<TMPL_LOOP Items>
<TMPL_IF new_date>
<h2><TMPL_VAR new_date></h2>
</TMPL_IF>

<div class="news-item-icon">
 <a href="<TMPL_VAR channel_link ESCAPE="HTML">"
    title="<TMPL_VAR channel_title ESCAPE="HTML">">
 <TMPL_VAR channel_name>
 <br/>
 <img class="embedded-face" alt=""
src="images/<TMPL_VAR channel_face ESCAPE="HTML">" >
 </a>
</div>

<div class="news-item">
 <TMPL_IF title>
 <h4><a href="<TMPL_VAR link ESCAPE="HTML">">
        <TMPL_VAR title></a></h4>
 </TMPL_IF>
 <div class="entry">
 <p>
 <TMPL_VAR content>
 </p>
 <p class="date">
 <a href="<TMPL_VAR link ESCAPE="HTML">">
<TMPL_IF creator>by <TMPL_VAR creator> at </TMPL_IF>
<TMPL_VAR date></a>
 </p>
 </div>
</div>

</TMPL_LOOP>

Shown in Listing 10 is the new stylesheet code to set the channel image on the left of the news item. Your Planet Me should now appear like Figure 2. If you prefer your channel icons to the right of the news item, change the stylesheet to have news-item-icon's float tag be right and news-item's margin-left be 0px.

div.news-item-icon {
	float: left;
	position: relative;
	left: 4px;
	margin-top: 25px;
	padding: 0 20px 30px 0;
	width: 120px;
	text-align: center;
}

div.news-item-icon a {
	text-decoration: none;
}

div.news-item {
	margin-left: 140px;
}

Figure 2. My Sample Planet Site with a Customized Template and CSS File

The face=whatever.png line used in the channel definition files is not special to Planet. You can define any other variables you want on a per-channel basis, and they will be available for use in your index.html.tmpl. For example, Listing 11 shows the use of an optional variable foo, which might be defined for a channel as foo=bar after a channel description in your config.ini file.

<TMPL_IF channel_foo>
Have foo:<TMPL_VAR channel_foo ESCAPE="HTML">
</TMPL_IF>

Another great way to learn how to customize your Planet Me is by visiting other Planet Web sites. Examine their HTML and CSS files to learn how they modified the look and feel.

The Planet code was designed to aggregate news feeds from many sources and supply a recent history of them on a single page. For local use with Planet Me, it is nice to be able to see a news feed for an arbitrary period in the past.

Your Planet Me will create a valid RSS RDF news feed that you can use to archive your Planet. All things in an RDF file revolve around triples. The three parts of a triple are referred to as the subject, predicate and object. An example triple might say that a news item has a given publication date, for example, item57 has-date 3-Jan-2006. An RSS news feed defines a news channel, associates that channel with a list of news items and defines interesting properties for each news item, such as its title, publication date and text content. Usually things like has-date are defined using long URIs to avoid two triples accidentally having the same literal value.

An easy, yet powerful way to archive your Planet's RSS is to use the Jena Project. Once you have a Java virtual machine installed, all you need to install Jena is to download a tarball, extract it and add it to your classpath.

Shown in Listing 12 are the installation steps and repeatable archiving process for news feeds. You could place your news feed archive into a database using Jena if you are collecting many feeds over a long time.

$ cd ~
$ unzip Jena-2.3.zip
$ edit ~/.bashrc
# append a handy classpath setup
JenaSetup() {
    for if in ~/Jena-2.3/lib/*.jar; do
	export CLASSPATH=$CLASSPATH:$if;
    done
}
$ . ~/.bashrc
$ JenaSetup

# archive news feed
# repeatable three step
$ cd ~/planet/me
$ mv -f archive.xml rss10-archive.xml
$ java jena.rdfcat rss10*xml >archive.xml

Jena gives you the ability to use very powerful queries against your archive to re-create your Planet.

Listing 13 shows a simple time interval query for news feeds. This query is in the SPARQL query language, which is used for querying RDF repositories. The core of the query links the channel, news item and date components before applying a filter to which news items are to be returned based on the date attached to that news item.