public function FilterBase::getHTMLRestrictions in Drupal 8

Same name and namespace in other branches

9 core/modules/filter/src/Plugin/FilterBase.php \Drupal\filter\Plugin\FilterBase::getHTMLRestrictions()

Returns HTML allowed by this filter's configuration.

May be implemented by filters of the FilterInterface::TYPE_HTML_RESTRICTOR type, this won't be used for filters of other types; they should just return FALSE.

This callback function is only necessary for filters that strip away HTML tags (and possibly attributes) and allows other modules to gain insight in a generic manner into which HTML tags and attributes are allowed by a format.

Return value

array|false A nested array with *either* of the following keys:

'allowed': (optional) the allowed tags as keys, and for each of those tags (keys) either of the following values:
- TRUE to indicate any attribute is allowed
- FALSE to indicate no attributes are allowed
- an array to convey attribute restrictions: the keys must be attribute names (which may use a wildcard, e.g. "data-*"), the possible values are similar to the above:
  - TRUE to indicate any attribute value is allowed
  - FALSE to indicate the attribute is forbidden
  - an array to convey attribute value restrictions: the key must be attribute values (which may use a wildcard, e.g. "xsd:*"), the possible values are TRUE or FALSE: to mark the attribute value as allowed or forbidden, respectively
'forbidden_tags': (optional) the forbidden tags

There is one special case: the "wildcard tag", "*": any attribute restrictions on that pseudotag apply to all tags.

If no restrictions apply, then FALSE must be returned.

Here is a concrete example, for a very granular filter:

array(
  'allowed' => array(
    // Allows any attribute with any value on the <div> tag.
    'div' => TRUE,
    // Allows no attributes on the <p> tag.
    'p' => FALSE,
    // Allows the following attributes on the <a> tag:
    //  - 'href', with any value;
    //  - 'rel', with the value 'nofollow' value.
    'a' => array(
      'href' => TRUE,
      'rel' => array(
        'nofollow' => TRUE,
      ),
    ),
    // Only allows the 'src' and 'alt' attributes on the <alt> tag,
    // with any value.
    'img' => array(
      'src' => TRUE,
      'alt' => TRUE,
    ),
    // Allow RDFa on <span> tags, using only the dc, foaf, xsd and sioc
    // vocabularies/namespaces.
    'span' => array(
      'property' => array(
        'dc:*' => TRUE,
        'foaf:*' => TRUE,
      ),
      'datatype' => array(
        'xsd:*' => TRUE,
      ),
      'rel' => array(
        'sioc:*' => TRUE,
      ),
    ),
    // Forbid the 'style' and 'on*' ('onClick' etc.) attributes on any
    // tag.
    '*' => array(
      'style' => FALSE,
      'on*' => FALSE,
    ),
  ),
);

A simpler example, for a very coarse filter:

array(
  'forbidden_tags' => array(
    'iframe',
    'script',
  ),
);

The simplest example possible: a filter that doesn't allow any HTML:

array(
  'allowed' => array(),
);

And for a filter that applies no restrictions, i.e. allows any HTML:

FALSE;

Overrides FilterInterface::getHTMLRestrictions

File

core/modules/filter/src/Plugin/FilterBase.php, line 146

Class

FilterBase: Provides a base class for Filter plugins.

Namespace

Drupal\filter\Plugin

Code

public function getHTMLRestrictions() {
  return FALSE;
}

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