soflomo/purifier

HTML Purifier integration module for Zend Framework 2

1.0.2 2016-03-10 20:32 UTC

README

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Soflomo\Purifier is the HTMLPurifier integration for Zend Framework 2.

It provides a Zend\Filter\FilterInterface implementation so you can use HTMLPurifier within your Zend\InputFilter classes. Furthermore, a view helper is provided to help purifying html on the fly in view scripts.

Installation

You can install Soflomo\Purifier through Composer

$: composer require soflomo/purifier

To enable the module in your ZF2 application, add an entry Soflomo\Purifier to the list of enabled modules in config/application.config.php.

Usage

In your input filter configuration, use the htmlpurifier as name in your filter spec.

An example Form:

class MyForm extends Zend\Form\Form implements Zend\InputFilter\InputFilterProviderInterface
{
    public function init()
    {
        $this->add([
            'name'    => 'text',
            'options' => [
                'label' => 'Text'
            ],
            'attributes' => [
                'type' => 'textarea',
            ],
        ]);
    }

    public function getInputFilterSpecification()
    {
        return [
            'text'  => [
                'required' => true,
                'filters'  => [
                    [ 'name' => 'stringtrim' ],
                    [ 'name' => 'htmlpurifier' ],
                ],
            ],
        ];
    }
}

or an InputFilter:

class MyInputFilter extends Zend\InputFilter\InputFilter
{
    public function init()
    {
        $this->add([
            'name'     => 'text',
            'required' => true,
            'filters'  => [
                [ 'name' => 'stringtrim' ],
                [ 'name' => 'htmlpurifier' ],
            ],
        ]);
    }
}

Alternatively, you can use the FQCN Soflomo\Purifier\PurifierFilter in place of the htmlpurifier alias.

If you're pulling the consumers from their respective plugin managers, this should work out-of-the-box. If not, please read how to inject the filter plugin manager.

If for some reason you want to use the filter in your view templates, you also have a view helper available. Please be aware that HTMLPurifier is not a very fast library and as such, filtering on every request can be a significant performance bottleneck. Be advised to use a caching mechanism to cache the output of the filtered html. The view helper is available under the key htmlPurifier:

<?php echo $this->htmlPurifier()->purify($foo->getText()) ?>

And there is a shorthand available too:

<?php echo $this->htmlPurifier($foo->getText()) ?>

Configuring HTMLPurifier

HTMLPurifier use the class HTMLPurifier_Config to configure its rules. Most configuration rules are based on a key/value pair: $config->set('HTML.Doctype', 'HTML 4.01 Transitional').

Global configuration

The HTMLPurifier_Config key/value storege is exposed by Soflomo\Purifier as an associative array into the ZF2 configuration, so you can customize the default HTMLPurifier_Config instance like this:

return [
    'soflomo_purifier' => [
        'config' => [
            'HTML.Doctype' => 'HTML 4.01 Transitional'
        ],
    ],
];

The configuration factory also handles a definitions sub array to add custom definitions to the purifier, as documented here.

For example:

return [
    'soflomo_purifier' => [
        'config' => [
            'HTML.DefinitionID' => 'my custom definitions',
        ], 
        'definitions' => [
            'HTML' => [
                'addAttribute' => [
                    [ 'a', 'target', 'Enum#_blank,_self,_target,_top' ]
                ],
            ],
        ],
    ],
];

This will add a HTMLPurifier_AttrDef_Enum definition for the target attribute of the a element. Note that an arbitrary value for the HTML.DefinitionID config key is required to correctly load the definition.

Definitions can also be set under the definitions key in the config array. These will override the key in the soflomo_purifier array.

Per-instance configuration

You can also set a different configuration each time you add the filter with a spec using the usual options key:

class MyInputFilter extends Zend\InputFilter\InputFilter
{
    public function init()
    {
        $this->add([
            'name'     => 'text',
            'required' => true,
            'filters'  => [
                [ 'name' => 'stringtrim' ],
                [
                    'name' => 'htmlpurifier',
                    'options' => [
                        'purifier_config' => [
                            'HTML.AllowedElements' => 'a, span'
                        ],
                    ],
                ],
            ],
        ]);
    }
}

Injecting the FilterManager

If you instantiate your forms or your input filters manually with the new keyword, rather than pulling them from their respective plugin managers (i.e. FormElementManager and InputFilterManager), the FilterManager is not injected automatically into their factories, and these will resort to use a default one.

As such, you get a ServiceNotFoundException: Zend\Filter\FilterPluginManager::get was unable to fetch or create an instance for htmlpurifier. This means the filter plugin manager was lazily instantiated, and does not know about the htmlpurifier plugin.

You can hack your way through this by executing the initializers manually:

$form = new MyForm();
$formElementManager = $serviceManager->get('FormElementManager');
$formElementManager->injectFactory($form);

// same goes for input filters
$inputFilter = new MyInputFilter();
$inputFilterManager = $serviceManager->get('InputFilterManager');
$inputFilterManager->populateFactory($inputFilter);

It is however strongly advised to pull forms and input filters from their respective plugin managers, and use the init() method (which will be invoked after all the factories are injected) when applicable.

Performance optimization

HTMLPurifier is not the fastest library. It uses a large number of classes and files so autoloading can be cumbersome.

Luckily, you can create a standalone version of the HTMLPurifier class, where a single file contains most of the classes.

The script in vendor/bin/purifier-generate-standalone generates this file for you. The standalone file is created inside vendor/ezyang/htmlpurifier/library so make sure you can write in that directory.

Soflomo\Purifier helps you using this standalone version with the configuration option soflomo_purifier.standalone.

For example, you could add this in your config/autoload/local.php:

return [
    'soflomo_purifier' => [
        'standalone' => true,
    ],
];

If you want to place the standalone file somewhere else, you can set its path too:

return [
    'soflomo_purifier' => [
        'standalone'      => true,
        'standalone_path' => 'path/to/HTMLPurifier.standalone.php',
    ],
];

Note: The standalone generator script requires HTMLPurifier to be installed either with version <4.7.0 or with Composer --prefer-source flag, because since that version the maintenance tools were removed from the archive (see htmlpurifier #65).