Tag Archives: zend framework

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.

Media RSS and ZF – Part 2

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Here’s the promised chunk of code making the most simple bridge between Zend Framework and Media RSS.

Step 1

Just add a simple action in a controller:

class IndexController extends Zend_Controller_Action
{
	public function indexAction()
	{
	    $this->getResponse()->setHeader('Content-Type', 'application/xml');
	    $this->view->somevar = 'some value';
 
	    echo $this->view->render('index/index.xml');
 
	    $this->_helper->layout()->disableLayout();
	    $this->_helper->viewRenderer->setNoRender(true);
	}
}

Step 2

After you’ve setup the xml file as a view script – you can simply access it as a normal Zend Framework view:

<rss version="2.0" xmlns:media="http://search.yahoo.com/mrss/" xmlns:av="http://www.searchvideo.com/schemas/av/1.0">
  <channel>
   <title><?php echo $this->somevar ?></title>
   ...
   other media rss elements
   ...
</channel>
</rss>

Zend Framework and Media RSS

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The Problem

Since native RSS format is not designed to deliver media content, there is a need for newer format supporting video and audio. There is such format – Media RSS introduced by Yahoo! in 2004. Actually now RSS supports some king of pseudo audio and video with the enclosure tag.

Inserting Media In RSS with Media RSS

Although there is a standardized format, there is not a Zend Framework native module. There is however a proposal, but that’s far not enough.

Possible Solutions

For me there are two possible solutions. The first is writing Zend_Feed_Mrss and extend the Zend_Feed_Rss functionality, but that appears to be a non-trivial task. The second solution is to write custom view returning XML, which I’m choosing for now. I hope I can paste some code soon!