README

• Overview
• Install
• Quickstart
• Extending
• Excludes

Overview

pop-filter is a component for applying filtering callbacks to values that need to be consumed by other areas of an application. It can be used for input security as well general input scrubbing as well.

pop-filter is a component of the Pop PHP Framework.

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Install

Install pop-filter using Composer.

composer require popphp/pop-filter

Or, require it in your composer.json file

"require": {
    "popphp/pop-filter" : "^4.0.4"
}

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Quickstart

Simple Filter

If you want to create a simple, single filter and use it to filter some values, you can do this:

$filter = new Pop\Filter\Filter('strip_tags');
$values = [
    'username' => '<b>admin</b>',
    'email'    => '<a href="mailto:test@test.com">test@test.com</a>'
];
$values = $filter->filter($values);

The values above have been filtered and had the tags stripped:

$values = [
    'username' => 'admin',
    'email'    => 'test@test.com'
];

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Extending

The Filterable Trait

The component comes with a trait called Pop\Filter\FilterableTrait. If you wish to have the filter component and its features included in your application, you can create a class that uses this trait. With it, your class will be able to add filters and call the methods to filter the necessary values. These filters can either be an instance of Pop\Filter\FilterInterface (e.g., Pop\Filter\Filter) or a basic callable.

namespace MyApp\Model

use Pop\Filter\FilterableTrait;

class User
{
    
    use FilterableTrait;

    /**
     * Filter values
     *
     * @param  array $values
     * @return array
     */
    public function filter(array $values)
    {
        foreach ($this->filters as $filter) {
            foreach ($values as $key => $value) {
                $values[$key] = $filter->filter($value, $key);
            }
        }

        return $values;
    }

} 

With the above code, you can create a user model, add filters to it and filter values with it:

$user = new User();
$user->addFilters([
    'strip_tags',
    new Pop\Filter\Filter('htmlentities', [ENT_QUOTES, 'UTF-8']),
]);

$values = [
    'username'   => '<script>"Admin"</script>',
    'first_name' => '<b>John\'s</b>',
    'last_name'  => '<b>Doe</b>'
];

$values = $user->filter($values);

The values are now filtered and look like:

$values = [
    'username'   => '"Admin"',
    'first_name' => 'John's',
    'last_name'  => 'Doe'
];

The tags have been stripped and the entities have been converted to HTML. Notice the first filter added was the callable strip_tags and the second filter added was an instance of Pop\Filter\Filter with parameters.

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Excludes

Fine-Grained Control

Two properties are available to the filter method within the Pop\Filter\AbstractFilter class. They are excludeByName and excludeByType. With them, you can have fine-tuned control over what values actually get filtered. For example, if you don't want to filter any values named username, you can do this:

$filter = new Pop\Filter\Filter('strip_tags', null, 'username');
$values = [
    'username' => '<b>admin</b>',
    'email'    => '<a href="mailto:test@test.com">test@test.com</a>'
];

foreach ($values as $key => $value) {
    $values[$key] = $filter->filter($value, $key);
}

Because of the third parameter in the above constructor, the username is excluded from being filtered and the values look like this:

$values = [
    'username' => '<b>admin</b>',
    'email'    => 'test@test.com'
];

The fourth parameter of the filter constructor is $excludeByType and that is useful for excluding a number of values at once that are all of the same type, for example, textareas within a form object.

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