Building Twig Tags

Custom Twig filters and functions can be registered in the CMS with the registerMarkupTags method of the plugin registration class. This article describes how to register your own Twig filters and functions that can be used in the CMS and mail templates.

public function registerMarkupTags()
{
    return [
        'filters' => [
            // ...Filters defined here
        ],
        'functions' => [
            // ...Functions defined here
        ]
    ];
}

# Registering a Filter

The filters key in the registration array may be used for Twig filters. For example, the |plural filter can be mapped to the global PHP function str_plural() with the following value.

'filters' => [
    'plural' => 'str_plural'
]

You may also pass a local method. For example, |uppercase can be mapped to the $this->makeAllCaps() method.

'filters' => [
    'uppercase' => [$this, 'makeTextAllCaps']
]

This becomes available in Twig as the following.

{{ 'my text'|uppercase }}

# Registering a Function

Just like filters, the functions key can be used to create Twig function. For example, the function could map to a static method call of Form::open() instead.

'functions' => [
    'form_open' => [Form::class, 'open']
]

Static calls also support wildcard definitions. In this example, a function call of url_foobar() will translate to a method call of Url::foobar and so on.

'functions' => [
    'url_*' => [Url::class, '*'],
]

Passing a closure is also allowed for either definition.

'functions' => [
    'hello_world' => function() { return 'Hello World!'; }
]

This is now available in Twig as the following.

{{ hello_world() }}