Overriding Zend form element default decorators, for good!

Phil — Thu, 15 Oct 2009 01:55:22 +0000

I’m sure everybody who has used Zend_Form has, at one time or another, wished they could change the default form element decorators in one fell swoop, simply and efficiently.

Up until now, I’ve been using one of two methods to override the default “definition list” style; set each element’s decorator scheme on instantiation or, use the form’s “setElementDecorators” method to reset the scheme for nominated elements. No longer!

Using just a few simple classes, I’ll show you how to permanently alter the default decorator scheme, thus simplifying your code and making it ultimately more flexible.

For the following example, I’ll assume a decorator scheme like the following

form
  fieldset
    ol
      li
        label
        element
      li
        button

Lets start by extending Zend_Form_Element. I’d also like to take this opportunity to introduce my new “Tolerable” library.

// library/Tolerable/Form/Element.php
 
class Tolerable_Form_Element extends Zend_Form_Element
{
    /**
     * Load default decorators
     *
     * @return void
     */
    public function loadDefaultDecorators()
    {
        if ($this->loadDefaultDecoratorsIsDisabled()) {
            return;
        }
 
        $decorators = $this->getDecorators();
        if (empty($decorators)) {
            $this->addDecorator('ViewHelper')
                 ->addDecorator('Errors')
                 ->addDecorator('Description', array('tag' => 'p',
                                                     'class' => 'description'))
                 ->addDecorator('Label', array('requiredSuffix' => ' *'))
                 ->addDecorator('HtmlTag', array('tag' => 'li',
                                                 'id'  => $this->getName() . '-element'));
        }
    }
}

Don’t forget to add your library namespace to the auto loader

; application/configs/application.ini
 
autoloaderNamespaces.1 = "Tolerable_"

Zend_Form_Element_Submit also needs some treatment

// library/Tolerable/Form/Element/Submit.php
 
class Tolerable_Form_Element_Submit extends Zend_Form_Element_Submit
{
    /**
     * Default decorators
     *
     * Uses only 'Submit' and 'li' decorators by default.
     * 
     * @return void
     */
    public function loadDefaultDecorators()
    {
        if ($this->loadDefaultDecoratorsIsDisabled()) {
            return;
        }
 
        $decorators = $this->getDecorators();
        if (empty($decorators)) {
            $this->addDecorator('Tooltip')
                 ->addDecorator('ViewHelper')
                 ->addDecorator('HtmlTag', array('tag' => 'li'));
        }
    }
}

We’ll also need to provide our own display group class to support the desired scheme

// library/Tolerable/Form/DisplayGroup.php
 
class Tolerable_Form_DisplayGroup extends Zend_Form_DisplayGroup
{
    /**
     * Load default decorators
     * 
     * @return void
     */
    public function loadDefaultDecorators()
    {
        if ($this->loadDefaultDecoratorsIsDisabled()) {
            return;
        }
 
        $decorators = $this->getDecorators();
        if (empty($decorators)) {
            $this->addDecorator('Description', array('tag'   => 'li',
                                                     'class' => 'group_description'))
                 ->addDecorator('FormElements')
                 ->addDecorator('HtmlTag', array('tag' => 'ol'))
                 ->addDecorator('Fieldset');
        }
    }
}

as well as a custom form class

// library/Tolerable/Form.php
 
class Tolerable_Form extends Zend_Form
{
    /**
     * Default display group class
     * @var string
     */
    protected $_defaultDisplayGroupClass = 'Tolerable_Form_DisplayGroup';
 
    /**
     * Constructor
     *
     * Add custom prefix path before parent constructor
     *
     * @param mixed $options
     * @return void
     */
    public function __construct($options = null)
    {
        $this->addPrefixPath('Tolerable_Form', 'Tolerable/Form');
        parent::__construct($options);
    }
 
    /**
     * Load the default decorators
     *
     * @return void
     */
    public function loadDefaultDecorators()
    {
        if ($this->loadDefaultDecoratorsIsDisabled()) {
            return;
        }
 
        $decorators = $this->getDecorators();
        if (empty($decorators)) {
            $this->addDecorator('FormElements')
                 ->addDecorator('Form');
        }
    }
}

Now that we’ve laid the way for our custom decorator scheme, there’s only one item remaining and I can’t say that I’m proud but hey, it works.

All front facing (HTML) Zend form elements extend the empty, abstract class Zend_Form_Element_Xhtml. We’re going to override this class in its current form. This method works well if the Zend Framework is not in the application’s “library” which should have a higher “include path” setting than the framework itself. Otherwise, you’ll just have to override the existing Zend Framework file.

// library/Zend/Form/Element/Xhtml.php
 
abstract class Zend_Form_Element_Xhtml extends Tolerable_Form_Element
{
}

That’s it. Get ready to start writing leaner, meaner forms

$form = new Tolerable_Form;
$form->addElement('text', 'foo', array(
    'label'    => 'Foo',
    'required' => true
))->addElement('textarea', 'bar', array(
    'label'    => 'Bar'
))->addElement('submit', 'submit_btn', array(
    'label'    => 'Submit'
))->addDisplayGroup(
    array('foo', 'bar', 'submit_btn'),
    'baz',
    array('legend' => 'My Form')
);

Zend Framework Forms and magic_quotes_gpc

Phil — Fri, 10 Oct 2008 02:05:45 +0000

Introducing the bane of my existence – PHP’s magic_quotes_gpc.

I won’t bore you with the details suffice to say that this is one of PHP’s greatest failings and I cannot wait until the world adopts PHP6 and this awful blight is removed forever. Until then, we’ll just have to deal with it.

Now, there are various ways of disabling this “feature” as outlined here but what if that isn’t an option? My particular host of choice, while being excellent in every other regard, has this little blighter enabled and runs PHP as a CGI via the suExec module. This means no php_flag or php_value entries in the .htaccess file and the current implementation of allowing custom php.ini files is totally broken (server php.ini items do not cascade through to the custom one, meaning paths are wrong, extensions aren’t loaded, etc). This prompted me to implement something in code which is what I’ll be sharing with you today.

The code solution to magic quotes is to use stripslashes(). The simplest way of getting this into the Zend Framework is to create a filter.

class MoreCowbell_Filter_StripSlashes implements Zend_Filter_Interface
{
    public function filter($value)
    {
        return get_magic_quotes_gpc() ? $this->_clean($value) : $value;
    }
 
    protected function _clean($value)
    {
        return is_array($value) ? array_map(array($this, '_clean'), $value) : stripslashes($value);
    }
}

This filter allows us to process not only strings but array values as well. Note that the filter only activates if magic quotes is enabled.

All my forms extend my own custom Zend_Form extension which simply provides some shortcuts to my preferred decorator scheme. I’ll add some extra shortcuts for the new filter.

class MoreCowbell_Form extends Zend_Form
{
    public $elementDecorators = array(
        'ViewHelper',
        'Description',
        array('Label',   array('requiredSuffix' => ' *')),
        array('Errors',  array('placement' => 'PREPEND')),
        array('HtmlTag', array('tag' => 'li'))
    );
 
    public $buttonDecorators = array(
        'ViewHelper',
        array('HtmlTag', array('tag' => 'li'))
    );
 
    public $groupDecorators = array(
        'FormElements',
        array('HtmlTag', array('tag' => 'ol')),
        'Fieldset'
    );
 
    // Configure path to custom plugins
    public $elementPrefixPaths = array('filter' => array(
        'prefix' => 'MoreCowbell_Filter',
        'path'   => 'MoreCowbell/Filter'
    ));
 
    // Shortcut to default element filters
    public $elementFilters = array(
        'StripSlashes'
    );
 
    public function loadDefaultDecorators()
    {
        $this->setDecorators(array(
            'FormElements',
            'Form'
        ));
    }
}

All that’s left to do is assign the appropriate configuration settings in your forms and all your input data will be purged of the magic quotes evil. Here’s an overly simple example of a blog entry form.

class My_Blog_Form extends MoreCowbell_Form
{
    public function init()
    {
        $this->addElement('text', 'blog_title', array(
            'label'      => 'Title',
            'required'   => true,
            'prefixPath' => $this->elementPrefixPaths,
            'decorators' => $this->elementDecorators,
            'filters'    => $this->elementFilters
        ))->addElement('textarea', 'blog_post', array(
            'label'      => 'Post',
            'required'   => true,
            'rows'       => 5,
            'cols'       => 10,
            'prefixPath' => $this->elementPrefixPaths,
            'decorators' => $this->elementDecorators,
            'filters'    => $this->elementFilters
        ))->addElement('submit', 'submit_btn', array(
            'label'      => 'Submit',
            'decorators' => $this->buttonDecorators
        ))->addDisplayGroup(
            array('blog_title', 'blog_post', 'submit_btn'),
            'blog',
            array(
                'legend'     => 'Blog Entry',
                'decorators' => $this->groupDecorators
            )
        );
    }
}

Phil Brown's Web Development Blog » forms

Overriding Zend form element default decorators, for good!

Zend Framework Forms and magic_quotes_gpc