Tag Archives: PHP programming language

Models in Zend Framework – Initialize All Methods with init()

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In the Zend Framework’s documentation there are lots of examples how you can initialize all the actions in a given controller – by simply adding the init() public method in the controller’s code:

<?php
 
class IndexController extends Zend_Controller_Action
{
	public function init()
	{
		echo 'foo';	
	}	
 
	public function indexAction()
	{
		// first the 'foo' string will be printed
		echo 'bar';	
	}
}

But did you know that you can do the same thing with any model in ZF? However you can setup a cache for every method or something else, but definitely it will execute for every method:

<?php
 
class MyModel
{
	public function init()
	{
		// prepare the cache setup
	}	
 
	public function readAll()
	{
		// the cache is already setup
		$sql = '...';
		// ...
	}
}

Of course that means that directly calling the readAll() function the init() method is called also – automatically.

Conclusion

There are good and bad parts about this. You’ll have this code executed for every method and if you have twenty of them and the init() method is practically used for only a couple of the member functions – than this will be useless.

Setting Up Zend Framework with Modules

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Typical Zend App

Typically you’ve one module in your Zend App – the default one. In the basic installation of the framework, you put all the controllers, models and views directly in the application folder, as described below.

/application
	- /controllers
		- /IndexController.php
	- /models
		- /MyModel.php
	- /views
		- /scripts
			- /index/index.phtml
/library
	- /Zend
/public_html
	- /images
	- /scripts

Bigger Apps – More Code

When the application becomes bigger and bigger the controller, models and views/scripts directories contain more and more files. That’s a bit odd, because it becomes difficult to maintain, and than the modules come in hand.

Modules in a Zend App

When it comes to setting up modular Zend App there are tons of articles in the web, but let me show you a simple directory layout and … sample code that sets up the framework.

/application
	- /modules
		+ /admin
			- /controllers
				- /IndexController.php
			- /views
				- /scripts
					- /index/index.phtml
		+ /default
			- /controllers
				- /IndexController.php
			- /views
				- /scripts
					- /index/index.phtml
	- /models
/library
	- /Zend
/public_html
	- /images
	- /scripts

Source

Simply add this into the bootstrap:

$frontController->addModuleDirectory(APPLICATION_PATH . '/modules');

Zend_Validate_Db_RecordExists in Zend Framework 1.10+

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Zend_Validate_Db_RecodExists is an extremely useful validator in Zend Framework when you’d like to be sure that a give row exists. Now it seems to be even better. Before you could check for a specific row by only comparing a value to the specified column:

$validator = new Zend_Validate_Db_RecordExists('db_table_name', 'column_name');
if ($validator->isValid(122)) {
   ...
}

which made it useless when you’d like to compare by more than one column. Now this is changed and you can even exclude given rows by adding an exclude clause.

$validator = new Zend_Validate_Db_NoRecordExists(
    array(
        'table' => 'users',
        'field' => 'username',
        'exclude' => array(
            'field' => 'id',
            'value' => $user_id
        )
    )
);

Setting Up Global Cache in Zend Framework

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In a large scale web application, especially based on Zend Framework, there are lot’s of components that support built in cache support. Such are Zend_Db, Zend_Translate, Zend_Date, etc. Also you may need cache support wherever in the app, so my advice is to setup a cache instance in the “beginning”, into the bootstrap.php or even better – into a front controller plugin, and to store it into the Zend_Registry. Thus you’ve to change only the lifetime for specific needs:

<?php
 
class CacheInit extends Zend_Controller_Plugin_Abstract
{
    public function __construct()
    {
        $frontendOptions = array(
            'automatic_serialization' => true,
            'lifetime' => 60
        );
 
        $backendOptions  = array(
            'cache_dir' => realpath(APPLICATION_PATH . '/../cache')
        );
 
        $cache = Zend_Cache::factory('Core',
                                     'File',
                                     $frontendOptions,
                                     $backendOptions);
 
        Zend_Registry::set('cache', $cache);
    }
}

Than add it as a front controller plugin:

// cache plugin
$frontController->registerPlugin(new CacheInit());

Zend Framework: Cache Database Table Schemes

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If you’re familiar with Zend Framework, you should know how to turn your database tables into models. Simply extend the Zend_Db_Table class. This is the very general example. There are lots of variations how to name the model classes and what member variables they can have.

<?
class User extends Zend_Db_Table
{}

The question is …

The question is how the framework knows what columns there are in a given table. That’s done by PHP on every call of the class, and the question is: isn’t that too slow? Yes it is and there’s a solution – to cache the table’s schema:

Zend_Db_Table_Abstract::setDefaultMetadataCache($cache);

Is there any problem?

Why it isn’t a default behavior when it’s so good? Because you’ve first to setup the cache, which is not always permitted – at least you’ve to have writing permissions. And on the second place if you’re rapidly developing the system and you change the database schema too frequently, you’ve to clear the cache every time. So it’s a good solution for the production server, but you can skip it while developing.