Build a Perl RSS Aggregator with Templating Tools (
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In this third part of a five-part series on templating tools, you'll learn how to write a simple RSS aggregator, and more. It is excerpted from chapter three of the book Advanced Perl Programming, Second Edition, written by Simon Cozens (O'Reilly; ISBN: 0596004567). Copyright © 2007 O'Reilly Media, Inc. All rights reserved. Used with permission from the publisher. Available from booksellers or direct from O'Reilly Media.
Loops
If we're going to get anywhere with our RSS example, we'll need to loop over a series of items--the stories in our newsreel. Thankfully, HTML::Template provides the <TMPL_LOOP> pseudotag for treating a variable as an array. For instance, the following code:
<ul>
<TMPL_LOOP NAME=STORIES>
<li> From <TMPL_VAR NAME=FEED_NAME>: <TMPL_VAR NAME=STORY_NAME> </li>
</TMPL_LOOP>
</ul>
when provided the appropriate data structure, loops over the items in the STORIES array reference and produces output like so:
<ul>
-
<li>
-
From Slashdot: NASA Finds Monkeys on Mars </li>
-
-
<li>
-
From use.perl: Perl 6 Release Predicted for 2013 </li>
</ul>
The trick is that the array reference needs to contain an array of hashes, and each hash provides the appropriate variable names:
$template->param(STORIES => [
{ FEED_NAME => "Slashdot", STORY_NAME => "NASA Finds Monkeys on Mars" },
{ FEED_NAME => "use.perl", STORY_NAME => "Perl 6 Release Predicted for 2013" }
]);
