public static ActiveLinkResponseFilter::setLinkActiveClass($html_markup, $current_path, $is_front, $url_language, array $query)
Sets the "is-active" class on relevant links.
This is a PHP implementation of the drupal.active-link JavaScript library.
@todo Once a future version of PHP supports parsing HTML5 properly (i.e. doesn't fail on https://www.drupal.org/comment/7938201#comment-7938201) then we can get rid of this manual parsing and use DOMDocument instead.
Parameters
string $html_markup.: The HTML markup to update.
string $current_path: The system path of the currently active page.
bool $is_front: Whether the current page is the front page (which implies the current path might also be <front>).
string $url_language: The language code of the current URL.
array $query: The query string for the current URL.
Return value
string The updated HTML markup.
File
- core/lib/Drupal/Core/EventSubscriber/ActiveLinkResponseFilter.php, line 126
Class
- ActiveLinkResponseFilter
- Subscribes to filter HTML responses, to set the 'is-active' class on links.
Namespace
Drupal\Core\EventSubscriber
Code
public static function setLinkActiveClass($html_markup, $current_path, $is_front, $url_language, array $query) {
$search_key_current_path = 'data-drupal-link-system-path="' . $current_path . '"';
$search_key_front = 'data-drupal-link-system-path="<front>"';
$offset = 0;
// There are two distinct conditions that can make a link be marked active:
// 1. A link has the current path in its 'data-drupal-link-system-path'
// attribute.
// 2. We are on the front page and a link has the special '<front>' value in
// its 'data-drupal-link-system-path' attribute.
while (strpos($html_markup, $search_key_current_path, $offset) !== FALSE || ($is_front && strpos($html_markup, $search_key_front, $offset) !== FALSE)) {
$pos_current_path = strpos($html_markup, $search_key_current_path, $offset);
// Only look for links with the special '<front>' system path if we are
// actually on the front page.
$pos_front = $is_front ? strpos($html_markup, $search_key_front, $offset) : FALSE;
// Determine which of the two values is the next match: the exact path, or
// the <front> special case.
$pos_match = NULL;
if ($pos_front === FALSE) {
$pos_match = $pos_current_path;
}
elseif ($pos_current_path === FALSE) {
$pos_match = $pos_front;
}
elseif ($pos_current_path < $pos_front) {
$pos_match = $pos_current_path;
}
else {
$pos_match = $pos_front;
}
// Find beginning and ending of opening tag.
$pos_tag_start = NULL;
for ($i = $pos_match; $pos_tag_start === NULL && $i > 0; $i--) {
if ($html_markup[$i] === '<') {
$pos_tag_start = $i;
}
}
$pos_tag_end = NULL;
for ($i = $pos_match; $pos_tag_end === NULL && $i < strlen($html_markup); $i++) {
if ($html_markup[$i] === '>') {
$pos_tag_end = $i;
}
}
// Get the HTML: this will be the opening part of a single tag, e.g.:
// <a href="/" data-drupal-link-system-path="<front>">
$tag = substr($html_markup, $pos_tag_start, $pos_tag_end - $pos_tag_start + 1);
// Parse it into a DOMDocument so we can reliably read and modify
// attributes.
$dom = new \DOMDocument();
@$dom->loadHTML('<!DOCTYPE html><html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /></head><body>' . $tag . '</body></html>');
$node = $dom->getElementsByTagName('body')->item(0)->firstChild;
// Ensure we don't set the "active" class twice on the same element.
$class = $node->getAttribute('class');
$add_active = !in_array('is-active', explode(' ', $class));
// The language of an active link is equal to the current language.
if ($add_active && $url_language) {
if ($node->hasAttribute('hreflang') && $node->getAttribute('hreflang') !== $url_language) {
$add_active = FALSE;
}
}
// The query parameters of an active link are equal to the current
// parameters.
if ($add_active) {
if ($query) {
if (!$node->hasAttribute('data-drupal-link-query') || $node->getAttribute('data-drupal-link-query') !== Json::encode($query)) {
$add_active = FALSE;
}
}
else {
if ($node->hasAttribute('data-drupal-link-query')) {
$add_active = FALSE;
}
}
}
// Only if the path, the language and the query match, we set the
// "is-active" class.
if ($add_active) {
if (strlen($class) > 0) {
$class .= ' ';
}
$class .= 'is-active';
$node->setAttribute('class', $class);
// Get the updated tag.
$updated_tag = $dom->saveXML($node, LIBXML_NOEMPTYTAG);
// saveXML() added a closing tag, remove it.
$updated_tag = substr($updated_tag, 0, strrpos($updated_tag, '<'));
$html_markup = str_replace($tag, $updated_tag, $html_markup);
// Ensure we only search the remaining HTML.
$offset = $pos_tag_end - strlen($tag) + strlen($updated_tag);
}
else {
// Ensure we only search the remaining HTML.
$offset = $pos_tag_end + 1;
}
}
return $html_markup;
}
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