data-caption attribute on <img> tags to caption images."),
* type = Drupal\filter\Plugin\FilterInterface::TYPE_TRANSFORM_REVERSIBLE
* )
*/
class FilterCaption extends FilterBase {
/**
* {@inheritdoc}
*/
public function process($text, $langcode) {
$result = new FilterProcessResult($text);
if (stristr($text, 'data-caption') !== FALSE) {
$dom = Html::load($text);
$xpath = new \DOMXPath($dom);
foreach ($xpath->query('//*[@data-caption]') as $node) {
// Read the data-caption attribute's value, then delete it.
$caption = Html::escape($node->getAttribute('data-caption'));
$node->removeAttribute('data-caption');
// Sanitize caption: decode HTML encoding, limit allowed HTML tags; only
// allow inline tags that are allowed by default, plus
.
$caption = Html::decodeEntities($caption);
$caption = FilteredMarkup::create(Xss::filter($caption, ['a', 'em', 'strong', 'cite', 'code', 'br']));
// The caption must be non-empty.
if (Unicode::strlen($caption) === 0) {
continue;
}
// Given the updated node and caption: re-render it with a caption, but
// bubble up the value of the class attribute of the captioned element,
// this allows it to collaborate with e.g. the filter_align filter.
$tag = $node->tagName;
$classes = $node->getAttribute('class');
$node->removeAttribute('class');
$node = ($node->parentNode->tagName === 'a') ? $node->parentNode : $node;
$filter_caption = [
'#theme' => 'filter_caption',
// We pass the unsanitized string because this is a text format
// filter, and after filtering, we always assume the output is safe.
// @see \Drupal\filter\Element\ProcessedText::preRenderText()
'#node' => FilteredMarkup::create($node->C14N()),
'#tag' => $tag,
'#caption' => $caption,
'#classes' => $classes,
];
$altered_html = \Drupal::service('renderer')->render($filter_caption);
// Load the altered HTML into a new DOMDocument and retrieve the element.
$updated_nodes = Html::load($altered_html)->getElementsByTagName('body')
->item(0)
->childNodes;
foreach ($updated_nodes as $updated_node) {
// Import the updated node from the new DOMDocument into the original
// one, importing also the child nodes of the updated node.
$updated_node = $dom->importNode($updated_node, TRUE);
$node->parentNode->insertBefore($updated_node, $node);
}
// Finally, remove the original data-caption node.
$node->parentNode->removeChild($node);
}
$result->setProcessedText(Html::serialize($dom))
->addAttachments([
'library' => [
'filter/caption',
],
]);
}
return $result;
}
/**
* {@inheritdoc}
*/
public function tips($long = FALSE) {
if ($long) {
return $this->t('
You can caption images, videos, blockquotes, and so on. Examples:
<img src="" data-caption="This is a caption" /><video src="" data-caption="The Drupal Dance" /><blockquote data-caption="Dries Buytaert">Drupal is awesome!</blockquote><code data-caption="Hello world in JavaScript.">alert("Hello world!");</code>
');
}
else {
return $this->t('You can caption images (data-caption="Text"), but also videos, blockquotes, and so on.');
}
}
}