ActiveLinkResponseFilter.php in Drupal 8
Same filename and directory in other branches
Namespace
Drupal\Core\EventSubscriberFile
core/lib/Drupal/Core/EventSubscriber/ActiveLinkResponseFilter.phpView source
<?php
namespace Drupal\Core\EventSubscriber;
use Drupal\Component\Serialization\Json;
use Drupal\Core\Language\LanguageInterface;
use Drupal\Core\Language\LanguageManagerInterface;
use Drupal\Core\Path\CurrentPathStack;
use Drupal\Core\Path\PathMatcherInterface;
use Drupal\Core\Session\AccountInterface;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Symfony\Component\HttpKernel\Event\FilterResponseEvent;
use Symfony\Component\HttpKernel\KernelEvents;
/**
* Subscribes to filter HTML responses, to set the 'is-active' class on links.
*
* Only for anonymous users; for authenticated users, the active-link asset
* library is loaded.
*
* @see system_page_attachments()
*/
class ActiveLinkResponseFilter implements EventSubscriberInterface {
/**
* The current user.
*
* @var \Drupal\Core\Session\AccountInterface
*/
protected $currentUser;
/**
* The current path.
*
* @var \Drupal\Core\Path\CurrentPathStack
*/
protected $currentPath;
/**
* The path matcher.
*
* @var \Drupal\Core\Path\PathMatcherInterface
*/
protected $pathMatcher;
/**
* The language manager.
*
* @var \Drupal\Core\Language\LanguageManagerInterface
*/
protected $languageManager;
/**
* Constructs a new ActiveLinkResponseFilter instance.
*
* @param \Drupal\Core\Session\AccountInterface $current_user
* The current user.
* @param \Drupal\Core\Path\CurrentPathStack $current_path
* The current path.
* @param \Drupal\Core\Path\PathMatcherInterface $path_matcher
* The path matcher.
* @param \Drupal\Core\Language\LanguageManagerInterface $language_manager
* The language manager.
*/
public function __construct(AccountInterface $current_user, CurrentPathStack $current_path, PathMatcherInterface $path_matcher, LanguageManagerInterface $language_manager) {
$this->currentUser = $current_user;
$this->currentPath = $current_path;
$this->pathMatcher = $path_matcher;
$this->languageManager = $language_manager;
}
/**
* Sets the 'is-active' class on links.
*
* @param \Symfony\Component\HttpKernel\Event\FilterResponseEvent $event
* The response event.
*/
public function onResponse(FilterResponseEvent $event) {
$response = $event
->getResponse();
// Only care about HTML responses.
if (stripos($response->headers
->get('Content-Type'), 'text/html') === FALSE) {
return;
}
// For authenticated users, the 'is-active' class is set in JavaScript.
// @see system_page_attachments()
if ($this->currentUser
->isAuthenticated()) {
return;
}
// If content is FALSE, assume the response does not support the
// setContent() method and skip it, for example,
// \Symfony\Component\HttpFoundation\BinaryFileResponse.
$content = $response
->getContent();
if ($content !== FALSE) {
$response
->setContent(static::setLinkActiveClass($content, ltrim($this->currentPath
->getPath(), '/'), $this->pathMatcher
->isFrontPage(), $this->languageManager
->getCurrentLanguage(LanguageInterface::TYPE_URL)
->getId(), $event
->getRequest()->query
->all()));
}
}
/**
* Sets the "is-active" class on relevant links.
*
* This is a PHP implementation of the drupal.active-link JavaScript library.
*
* @param string $html_markup
* The HTML markup to update.
* @param string $current_path
* The system path of the currently active page.
* @param bool $is_front
* Whether the current page is the front page (which implies the current
* path might also be <front>).
* @param string $url_language
* The language code of the current URL.
* @param array $query
* The query string for the current URL.
*
* @return string
* The updated HTML markup.
*
* @todo Once a future version of PHP supports parsing HTML5 properly
* (i.e. doesn't fail on
* https://www.drupal.org/comment/7938201#comment-7938201) then we can get
* rid of this manual parsing and use DOMDocument instead.
*/
public static function setLinkActiveClass($html_markup, $current_path, $is_front, $url_language, array $query) {
$search_key_current_path = 'data-drupal-link-system-path="' . $current_path . '"';
$search_key_front = 'data-drupal-link-system-path="<front>"';
// Receive the query in a standardized manner.
ksort($query);
$offset = 0;
// There are two distinct conditions that can make a link be marked active:
// 1. A link has the current path in its 'data-drupal-link-system-path'
// attribute.
// 2. We are on the front page and a link has the special '<front>' value in
// its 'data-drupal-link-system-path' attribute.
while (strpos($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;
}
/**
* {@inheritdoc}
*/
public static function getSubscribedEvents() {
// Should run after any other response subscriber that modifies the markup.
$events[KernelEvents::RESPONSE][] = [
'onResponse',
-512,
];
return $events;
}
}
Classes
Name | Description |
---|---|
ActiveLinkResponseFilter | Subscribes to filter HTML responses, to set the 'is-active' class on links. |