#552478 by pwolanin, samj, dropcube, and sun: Improve link/header API and support on node/comment pages rel=canonical and rel=shortlink standards.

2 files changed, 27 insertions, 40 deletions

diff --git a/modules/system/system.api.php b/modules/system/system.api.php
index 36a06df8d..339f82d04 100644
--- a/modules/system/system.api.php
+++ b/modules/system/system.api.php
@@ -2282,6 +2282,27 @@ function hook_drupal_goto_alter(&$path, &$options, &$http_response_code) {
 }
 
 /**
+ * Alter XHTML HEAD tags before they are rendered by drupal_get_html_head().
+ *
+ * Elements available to be altered are only those added using
+ * drupal_add_html_head_link() or drupal_add_html_head(). CSS and JS files
+ * are handled using drupal_add_css() and drupal_add_js(), so the head links
+ * for those files will not appear in the $head_elements array.
+ *
+ * @param $head_elements
+ *   An array of renderable elements. Generally the values of the #attributes
+ *   array will be the most likely target for changes.
+ */
+function hook_html_head_alter(&$head_elements) {
+  foreach($head_elements as $key => $element) {
+    if (isset($element['#attributes']['rel']) && $element['#attributes']['rel'] == 'canonical') {
+      // I want a custom canonical url.
+      $head_elements[$key]['#attributes']['href'] = mymodule_canonical_url();
+    }
+  }
+}
+
+/**
  * Alter the full list of installation tasks.
  *
  * @param $tasks
diff --git a/modules/system/system.module b/modules/system/system.module
index 0b587db77..da1089b92 100644
--- a/modules/system/system.module
+++ b/modules/system/system.module
@@ -179,12 +179,6 @@ function system_theme() {
     'system_powered_by' => array(
       'variables' => array(),
     ),
-    'meta_generator_html' => array(
-      'variables' => array('version' => NULL),
-    ),
-    'meta_generator_header' => array(
-      'variables' => array('version' => NULL),
-    ),
     'system_compact_link' => array(
       'variables' => array(),
     ),
@@ -318,6 +312,12 @@ function system_element_info() {
     '#ajax_commands' => array(),
   );
 
+  $types['html_tag'] = array(
+    '#theme' => 'html_tag',
+    '#attributes' => array(),
+    '#value' => NULL,
+  );
+
   // Input elements.
   $types['submit'] = array(
     '#input' => TRUE,
@@ -1718,22 +1718,6 @@ function system_init() {
 }
 
 /**
- * Implement MODULE_preprocess_HOOK().
- */
-function system_preprocess_page(&$variables) {
-  // Get the major version
-  list($version, ) = explode('.', VERSION);
-
-  // Emit the META tag in the HTML HEAD section
-  theme('meta_generator_html', array('version' => $version));
-
-  // Emit the HTTP Header too
-  theme('meta_generator_header', array('version' => $version));
-
-  $variables['head'] = drupal_get_html_head();
-}
-
-/**
  * Implement hook_form_FORM_ID_alter().
  */
 function system_form_user_profile_form_alter(&$form, &$form_state) {
@@ -2974,24 +2958,6 @@ function theme_system_compact_link() {
 }
 
 /**
- * Send Drupal and the major version number in the META GENERATOR HTML.
- *
- * @ingroup themeable
- */
-function theme_meta_generator_html($variables) {
-  drupal_add_html_head('<meta name="Generator" content="Drupal ' . $variables['version'] . ' (http://drupal.org)" />');
-}
-
-/**
- * Send Drupal and the major version number in the HTTP headers.
- *
- * @ingroup themeable
- */
-function theme_meta_generator_header($variables) {
-  drupal_add_http_header('X-Generator', 'Drupal ' . $variables['version'] . ' (http://drupal.org)');
-}
-
-/**
  * Implement hook_image_toolkits().
  */
 function system_image_toolkits() {