HomePHP Page 13 - Template-Based Web Development With patTemplate (part 2)
Crash Bang Boom - PHP
Got the basics down? Well, here's the advanced course - thisarticle demonstrates some of patTemplate's more sophisticated features,including the ability to dynamically show or hide templates, inheritvariables, use loops and conditional branches, and create dynamic,template-based forms and error handlers.
Another common use of patTemplate involves using it to display error and success codes while processing a script. Consider the following templates, which set up error and success pages respectively:
<!-- common.tmpl -->
<patTemplate:tmpl name="error">
<html>
<head><basefont face="Arial"></head>
<body>
An error occurred. Please contact the <a
href="mailto:webmaster@domain.com">webmaster</a>.
</body>
</html>
</patTemplate:tmpl>
<patTemplate:tmpl name="success">
<html>
<head><basefont face="Arial"></head>
<body>
The operation was successfully executed.
</body>
</html>
</patTemplate:tmpl>
Here's how I might use them in a script:
<?php
function checkErrors()
{
global $template, $error;
if ($error)
{
$template->displayParsedTemplate("error");
die;
}
}
function raiseError()
{
global $error;
$error = true;
}
// include the class
include("include/patTemplate.php");
// initialize an object of the class
$template = new patTemplate();
// set template location
$template->setBasedir("templates");
// add templates to the template engine
$template->readTemplatesFromFile("common.tmpl");
// set error variable
$error = false;
// script starts here
// process section 1
// no errors
checkErrors();
// process section 2
// let's assume an error occurred
raiseError();
checkErrors();
// process section 3
// no errors
checkErrors();
// end of script processing
// if we get this far, it means no errors
// display success code $template->displayParsedTemplate("success");
?>
In this case, since an error was raised in section two of the
script, the checkErrors() function will kill the script and display the error template when it is next invoked.
If, on the other hand, no errors are raised during execution of the script, the final call to checkErrors() will have no effect, the line following it will be executed and a success template will be displayed.
This is a fairly primitive example, but it does serve to demonstrate how a template engine can assist in creating powerful, flexible error handlers for your Web applications. It works like a charm most of the time - not to mention being fairly easy to maintain.
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