N2F Training Team Blogtorials

One of the new features introduced with v0.2 is the mod.ext.php feature.  This feature was a request from a few users and can be a useful way to add functionality to your system.

The premise behind mod.ext.php is similar to that of the sys.ext.php file.  However, instead of being included globally, the mod.ext.php file is only included when a specific module is brought into scope.  This is particularly helpful if you have large/complicated modules and need some classes or global information that is only necessary when that module is in use.

As an example, let’s pretend that we have a set of classes that are particularly large.  We only need these classes inside of our documentation module, so we use a mod.ext.php file to make that possible.  Our mod.ext.php is saved in the module directory at ~/modules/documentation/mod.ext.php, just like a sys.ext.php file.  The code in the file might look like this:

<?php

require('cls/docmgr.cls.php');
require('dat/docs.dat.php');

?>

Just as with the sys.ext.php files we don’t have to do anything special to use mod.ext.php.  Once you create one and the module is called, it will be automatically called into scope before the module’s code is executed.

- Andrew

In Yverdon v0.1, we added the ability to use sys.ext.php files inside of each module.  Their purpose is very simple and yet sometimes beautifully useful.

The Problem
Sometimes we find ourselves working on very large projects.  Inside of those large projects, the tendency is to have each developer concentrate on specific modules or extensions.  The module/extension layout works great in most situations, but it occurred to us that it wouldn’t always be appropriate to put certain system-wide functionality into an extension.  As an example, it would seem odd to build an entire extension just to create some template aliases for one level of the site.

The Solution
Our solution, the sys.ext.php file, allows a developer to include code system-wide on a particular directory level without having to create an extension.  The sys.ext.php files are included after all extensions have been included but before any modules are included.  This gives you the ability to use any of the constructs provided by your extensions and have your code execute before a page.php or data.php is called.  Going back to our example, you will see that the default installation’s main module has a sys.ext.php file inside of it, with the following contents:

<?php

/***********************************************\
* N2F Yverdon v0                              *
* Copyright (c) 2008 Zibings Incorporated     *
*                                             *
* You should have received a copy of the      *
* Microsoft Reciprocal License along with     *
* this program.  If not, see:                 *
* <http://opensource.org/licenses/ms-rl.html> *
\***********************************************/

// Create our template aliases
n2f_template_dynamic::addAlias('header', 'header', 'main', N2F_REL_PATH.'modules', 'default');
n2f_template_dynamic::addAlias('footer', 'footer', 'main', N2F_REL_PATH.'modules', 'default');

?>

This file only needs to be in the main module for all of the other modules in the root level to have access to it’s values.  The result of this code is that now all templates executed in the root level will now be able to use aliases for <%header%> and <%footer%>.

Conclusion
The sys.ext.php files are easy to use and very handy in certain situations.  Hopefully this blogtorial has been helpful in showing you the basic idea behind sys.ext.php files.  Yverdon v0.2 will also be introducing a new file, the mod.ext.php file, but we’ll talk about that when the time comes.  ;)

- Andrew