Zend_Applicaton to the rescue

Lets start with our website’s public/index.php – the script which sets up and launches an application. It looks roughly like this:

<?php
 
// Define path to application directory
defined('APPLICATION_PATH')
    || define('APPLICATION_PATH',
              realpath(dirname(__FILE__) . '/../application'));
 
// Define application environment
defined('APPLICATION_ENV')
    || define('APPLICATION_ENV',
              (getenv('APPLICATION_ENV') ? getenv('APPLICATION_ENV')
                                         : 'production'));
 
require_once 'Zend/Application.php';
$application = new Zend_Application(
    APPLICATION_ENV,
    APPLICATION_PATH . '/configs/config.php'
);
 
$application->bootstrap()->run();

One feature of Zend Application is that you can choose to bootstrap only certain resources, rather than all of those referenced in your application config and bootstrap (_init methods.) The following assumes that our script needs to use the database, and send an email.

<?php
 
// Define path to application directory
defined('APPLICATION_PATH')
    || define('APPLICATION_PATH',
              realpath(dirname(__FILE__) . '/../application'));
 
// Define application environment
defined('APPLICATION_ENV')
    || define('APPLICATION_ENV',
              (getenv('APPLICATION_ENV') ? getenv('APPLICATION_ENV')
                                         : 'production'));
 
require_once 'Zend/Application.php';
$application = new Zend_Application(
    APPLICATION_ENV,
    APPLICATION_PATH . '/configs/config.php'
);
 
//only load resources we need for script, in this case db and mail
$application->bootstrap(array('db', 'mail'));

Having bootstrapped the resources, we can retrieve them from the application as follows:

$db = $application->getBootstrap()->getResource('db');
 
//do something!
$row = $db->fetchRow('SELECT * FROM something');

From the MySQL manual:

Before MySQL 5.1.17, prepared statements do not use the query cache. Beginning with 5.1.17, prepared statements use the query cache under certain conditions, which differ depending on the preparation method

This means that if you’re running MySQL 5.0.x, not uncommon at the time of writing, your applications are not going to benefit from the query cache. There’s a simple workaround, however:

If you’re using Pdo, set the following driver option:

$pdoParams = array(
    PDO::MYSQL_ATTR_USE_BUFFERED_QUERY => true
);
 
$params = array(
    'host'           => '127.0.0.1',
    'username'       => 'webuser',
    'password'       => 'xxxxxxxx',
    'dbname'         => 'test',
    'driver_options' => $pdoParams
);

Zend_Config_Ini [parse_ini_file()] doesn’t support class constants, so ini users will have to supply the value of PDO::MYSQL_ATTR_USE_BUFFERED_QUERY, 1000, in their configs:

resources.db.adapter         = pdo_mysql
resources.db.params.host     = localhost
resources.db.params.username = webuser
resources.db.params.password = xxxxxxxx
resources.db.params.dbname   = myDb
resources.db.params.driver_options.1000 = true

Your existing web server may already be set up to compress JavaScript and CSS, potentially saving hundreds of kb on the wire. In uploading and testing your assets on CloudFront you’ll soon realise that it doesn’t perform any gzipping or compression. How to benefit from Amazon’s superfast edge locations and smaller file sizes?

When your browser requests a page, the headers sent might look like the following:

Host: www.davidcaunt.co.uk
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-GB; rv:1.9.1.3) Gecko/20090824 Firefox/3.5.3 (.NET CLR 3.5.30729) FirePHP/0.3
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-US,en;q=0.8,en-gb;q=0.5,en-us;q=0.3
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 300
Connection: keep-alive
Referer: http://www.davidcaunt.co.uk/about/

The header we’re interested in here is Accept-Encoding – this denotes whether the browser can cope with gzipped assets, and is used by Apache to decide whether to compress them. We can use this header in our PHP scripts to reference pre-compressed assets, and here’s how:

1. Compress asset, e.g. home.css -> home.cssgz
2. Upload both files, home.css and home.cssgz to S3 (CloudFront)
3. Add PHP code to link to the compressed file if the browser accepts

You can easily compress assets on Linux using the following:

gzip home.css

In step 2, you’ll need to inform S3 that your assets are gzipped. S3 allows you to specify headers that will be sent with your file:

Content-Encoding: gzip

All good libraries and gui tools will help with this. It also makes sense to set Expires headers, if your assets are versioned.

Then the following PHP snippet should be all you need:

if (false !== strpos($_SERVER['HTTP_ACCEPT_ENCODING'], 'gzip')){
	$path = '/css/home.cssgz';
}else{
	$path = '/css/home.css';
}

You’ll want to integrate this code into your View Helpers (Zend Framework) or application code for generating asset URLs.

Note

You’ll notice I’ve named my file home.cssgz, not home.css.gz. I had problems with Safari PC (and probably Mac) refusing to use these files inline, and being disposed as attachments.

Zend Framework is excellent; this series of posts entitled ‘Zend Framework Pitfalls’ won’t try and dispute that. There are, however, one or two problems and poorly implemented components that can cause problems. Before using any library component it is important to be aware of any drawbacks and issues. It is then possible to make an objective decision before investing your time, and you can avoid banging your head against the desk understanding a known bug or problem that isn’t well documented.

Component

Zend_Auth

Priority

Minor (definition)

Problem

Zend_Auth is implemented as a singleton. This singleton references a single instance of Zend_Auth_Storage_Interface, used to persist an identity. This makes management of two or more authentication systems (e.g. frontend and admin) difficult. You must manually set the storage each time you want to query a different identity.

Solution 1 – Don’t use multiple authentication systems

In most simple web applications, you can use a single user database (table) to store both common users and administrators, and expose administrator privileges as appropriate via Zend_Acl or similar.

Solution 2 – Toggle storage

Zend_Auth has a method for changing storage, setStorage. Calling this method every time before retrieving the identity object is viable, but you have to remember to do so every time or you could read the wrong storage. This can be wrapped up for practicality:

class My_Auth extends Zend_Auth {
 
	public static function getInstance($storageNamespace = 'Zend_Auth'){
 
		// set namespace
		$this->setStorage(new Zend_Auth_Storage_Session($storageNamespace));
 
		return parent::getInstance();
	}
 
}

Remember to use this getInstance method every time you need to access your auth (and namespace) rather than storing a reference to the Zend_Auth instance.

Solution 3 – Your own implementation of Zend_Auth

Zend_Auth doesn’t actually do much heavy lifting. You could write something that can take advantage of the other Zend_Auth_* components, without implementing the singleton pattern. This is suggested in the reference manual.

Summary

It is unlikely that Zend_Auth will be re-architected for the 2.0 release of Zend Framework, the earliest opportunity for a break in backwards compatibility. Whether the singleton pattern is appropriate is debatable and a strongly advantageous alternative solution would be necessary to justify any changes.

As always, your comments and solution suggestions are welcomed.

Zend_Image will initially support two adapters, Gd and Imagick (ImageMagick), and Gmagick support may be added in future. The following common image operations will be supported:

• Resize
• Rotate
• Watermark
• Filtering
• Format Conversion (e.g. JPG to PNG)
• Drawing (lines, arcs, ellipses, polygon, text)

Major benefits of Zend_Image include portability and a uniform API across adaptors. It will also be possible to define custom and composite actions for reuse.

We’re excited to proceed with development and hoping for inclusion in the forthcoming 1.10 release. We welcome your feedback on the proposal page if you have ideas or comments.

Fortunately there’s a fix which means the scrollbar is always displayed. Simply add this to your css:

html {
    overflow-y:scroll;
}

My intention is to write web development articles and tutorials, with a particular focus on Zend Framework and PHP. These are likely to be programming oriented, covering solutions to problems that are not already well documented on the web.