Purify

Purify is a Laravel wrapper around HTMLPurifier by ezyang.

Requirements

• PHP >= 7.4
• Laravel >= 7.0

Installation

To install Purify, run the following command in the root of your project:

composer require stevebauman/purify

Then, publish the configuration file using:

php artisan vendor:publish --provider="Stevebauman\Purify\PurifyServiceProvider"

Upgrading from v4 to v5

To upgrade from v4, install the latest version by running the below command in the root of your project:

composer require stevebauman/purify

Then, navigate into your published config/purify.php configuration file and copy the settings array -- except for the following keys:

• HTML.DocType:
• Core.Encoding:
• Cache.SerializerPath:

'settings' => [
-   'Core.Encoding' => 'utf-8',
-   'Cache.SerializerPath' => storage_path('app/purify'),
-   'HTML.Doctype' => 'XHTML 1.0 Strict',
+   'HTML.Allowed' => 'h1,h2,h3,h4,h5,h6,b,strong,i,em,a[href|title],ul,ol,li,p[style],br,span,img[width|height|alt|src]',
+   'HTML.ForbiddenElements' => '',
+   'CSS.AllowedProperties' => 'font,font-size,font-weight,font-style,font-family,text-decoration,padding-left,color,background-color,text-align',
+   'AutoFormat.AutoParagraph' => false,
+   'AutoFormat.RemoveEmpty' => false,
],

Important: If you've created a unique storage path for Cache.SerializerPath, take note of this as well, so you can migrate it into the new configuration file.

Once copied, delete the config/purify.php file, and run the below command:

php artisan vendor:publish --provider="Stevebauman\Purify\PurifyServiceProvider"

Then, inside the newly published config/purify.php configuration file, paste the keys (overwriting the current) into the configs.default array:

'configs' => [
    'default' => [
        'Core.Encoding' => 'utf-8',
        'HTML.Doctype' => 'HTML 4.01 Transitional',
+       'HTML.Allowed' => 'h1,h2,h3,h4,h5,h6,b,strong,i,em,a[href|title],ul,ol,li,p[style],br,span,img[width|height|alt|src]',
+       'HTML.ForbiddenElements' => '',
+       'CSS.AllowedProperties' => 'font,font-size,font-weight,font-style,font-family,text-decoration,padding-left,color,background-color,text-align',
+       'AutoFormat.AutoParagraph' => false,
+       'AutoFormat.RemoveEmpty' => false,
    ],
],

If you've created a unique serializer path (previously set via the old Cache.SerializerPath configuration key mentioned above), then you may reconfigure this in the new serializer configuration key:

'serializer' => storage_path('app/purify'),

You're all set!

Usage

Cleaning a String

To clean a users input, simply use the clean method:

$input = '<script>alert("Harmful Script");</script> <p style="border:1px solid black" class="text-gray-700">Test</p>';

// Returns '<p>Test</p>'
$cleaned = Purify::clean($input);

Cleaning an Array

Need to purify an array of user input? Just pass in an array:

$array = [
    '<script>alert("Harmful Script");</script> <p style="border:1px solid black" class="text-gray-700">Test</p>',
    '<script>alert("Harmful Script");</script> <p style="border:1px solid black" class="text-gray-700">Test</p>',
];

$cleaned = Purify::clean($array);

// array [
//  '<p>Test</p>',
//  '<p>Test</p>',
// ]
var_dump($cleaned);

Dynamic Configuration

Need a different configuration for a single input? Pass in a configuration array into the second parameter:

Note: Configuration passed into the second parameter is not merged with your default configuration.

$config = ['HTML.Allowed' => 'div,b,a[href]'];

$cleaned = Purify::config($config)->clean($input);

Configuration

Inside the configuration file, multiple HTMLPurifier configuration sets can be specified, similar to Laravel's built-in database, mail and logging config. Simply call Purify::config($name)->clean($input) to use another set of configuration.

For HTMLPurifier configuration documentation, please visit the HTMLPurifier Website:

http://htmlpurifier.org/live/configdoc/plain.html

Practices

If you're looking into sanitization, you're likely wanting to sanitize inputted user HTML content that is then stored in your database to be rendered onto your application.

In this scenario, it's likely best practice to sanitize on the way out instead of the on the way in. The database doesn't care what text it contains.

This way you can allow anything to be inserted in the database, and have strong sanization rules on the way out.

To accomplish this, you may use the provided PurifyHtmlOnGet cast class on your Eloquent model:

use Stevebauman\Purify\Casts\PurifyHtmlOnGet;

class Post extends Model
{
    protected $casts = [
        'content' => PurifyHtmlOnGet::class,
    ];
}

Or, implement it yourself via an Eloquent attribute mutator:

use Stevebauman\Purify\Facades\Purify;

class Post extends Model
{
    public function getContentAttribute($value)
    {
        return Purify::clean($value);
    }
}

You can even configure the configuration that is used when casting by appending it's name to the cast:

// config/purify.php

'configs' => [
    // ...

    'other' => [
        // Some configuration ...
    ],
]

protected $casts = [
    'content' => PurifyHtmlOnGet::class.':other',
];

This helps tremendously if you change your sanization requirements later down the line, then all rendered content will follow these sanization rules.

If you'd like to purify HTML while setting the value, you can use the inverse PurifyHtmlOnSet cast instead.

Custom HTML definitions

The HTML.Doctype configuration option denotes the schema to ultimately abide to. You may want to extend these schema definitions to support custom elements or attributes (e.g. <foo>...</foo>, or <span foo="...">) by specifying a custom HTML element "definitions".

Purify ships with additional HTML5 definitions that HTMLPurifier does not (yet) support of the box (via the Html5Definition class).

To create your own HTML definition, create a new class and have it implement Definition:

namespace App;

use HTMLPurifier_HTMLDefinition;
use Stevebauman\Purify\Definitions\Definition;

class CustomDefinition implements Definition
{
    /**
     * Apply rules to the HTML Purifier definition.
     *
     * @param HTMLPurifier_HTMLDefinition $definition
     *
     * @return void
     */
    public static function apply(HTMLPurifier_HTMLDefinition $definition)
    {
        // Customize the HTML purifier definition.
    }
}

Then, reference this class in the config/purify.php file in the definitions key:

// config/purify.php

'definitions' => \App\CustomDefinitions::class,

Here's an example for customizing the definition in order to support Basecamp's Trix WYSIWYG editor (credit to Antonio Primera):

namespace App;

use HTMLPurifier_HTMLDefinition;
use Stevebauman\Purify\Definitions\Definition;

class TrixPurifierDefinitions implements Definition
{
    /**
     * Apply rules to the HTML Purifier definition.
     *
     * @param HTMLPurifier_HTMLDefinition $definition
     *
     * @return void
     */
    public static function apply(HTMLPurifier_HTMLDefinition $definition)
    {
        $definition->addElement('figure', 'Inline', 'Inline', 'Common');
        $definition->addAttribute('figure', 'class', 'Text');
        $definition->addElement('figcaption', 'Inline', 'Inline', 'Common');
        $definition->addAttribute('figcaption', 'class', 'Text');
        $definition->addAttribute('figcaption', 'data-trix-placeholder', 'Text');

        $definition->addAttribute('a', 'rel', 'Text');
        $definition->addAttribute('a', 'tabindex', 'Text');
        $definition->addAttribute('a', 'contenteditable', 'Enum#true,false');
        $definition->addAttribute('a', 'data-trix-attachment', 'Text');
        $definition->addAttribute('a', 'data-trix-content-type', 'Text');
        $definition->addAttribute('a', 'data-trix-id', 'Number');

        $definition->addElement('span', 'Block', 'Flow', 'Common');
        $definition->addAttribute('span', 'data-trix-cursor-target', 'Enum#right,left');
        $definition->addAttribute('span', 'data-trix-serialize', 'Enum#true,false');

        $definition->addAttribute('img', 'data-trix-mutable', 'Enum#true,false');
        $definition->addAttribute('img', 'data-trix-store-key', 'Text');
    }
}