SEO: Add a rel canonical in all CMS pages (#4923)

* SEO: Add a canonical link in all CMS pages

* SEO: Add a canonical link in CMS homepage

* Added system config

* refactor(cms): update canonical URL methods and improve type hints

* fix(cms): ensure proper newline at end of Mage_Cms.csv

* Fix PHPStand

* Fixed  Rector

---------

Co-authored-by: Ng Kiat Siong <[email protected]>
Co-authored-by: Sven Reichel <[email protected]>

Author: 3 people

app/code/core/Mage/Cms/Block/Page.php

@@ -93,6 +93,14 @@ protected function _prepareLayout()
             $head->setTitle($page->getTitle());
             $head->setKeywords($page->getMetaKeywords());
             $head->setDescription($page->getMetaDescription());
+
+            // Add canonical tag if enabled
+            if (Mage::helper('cms')->canUseCanonicalTag()) {
+                $canonicalUrl = $this->getCanonicalUrl($page);
+                if ($canonicalUrl) {
+                    $head->addLinkRel('canonical', $canonicalUrl);
+                }
+            }
         }
 
         return parent::_prepareLayout();
@@ -113,4 +121,40 @@ protected function _toHtml()
         $html = $processor->filter($this->getPage()->getContent());
         return $this->getMessagesBlock()->toHtml() . $html;
     }
+
+    /**
+     * Get canonical URL for CMS page
+     */
+    protected function getCanonicalUrl(Mage_Cms_Model_Page $page): ?string
+    {
+        if (!$page->getId()) {
+            return null;
+        }
+
+        // Check if page is active
+        if (!$page->getIsActive()) {
+            return null;
+        }
+
+        // Get the page identifier
+        $identifier = $page->getIdentifier();
+
+        // Handle special pages differently
+        $homePageId = Mage::getStoreConfig('web/default/cms_home_page');
+        $noRoutePageId = Mage::getStoreConfig('web/default/cms_no_route');
+        $noCookiesPageId = Mage::getStoreConfig('web/default/cms_no_cookies');
+
+        // For homepage, use base URL
+        if ($identifier === $homePageId) {
+            return Mage::getBaseUrl(Mage_Core_Model_Store::URL_TYPE_WEB);
+        }
+
+        // For special pages that shouldn't have canonical tags
+        if (in_array($identifier, [$noRoutePageId, $noCookiesPageId])) {
+            return null;
+        }
+
+        // For regular CMS pages, use the standard CMS page URL
+        return $this->getUrl('', ['_direct' => $identifier, '_nosid' => true]);
+    }
 }

app/code/core/Mage/Cms/Helper/Data.php

@@ -18,6 +18,7 @@ class Mage_Cms_Helper_Data extends Mage_Core_Helper_Abstract
     public const XML_NODE_BLOCK_TEMPLATE_FILTER    = 'global/cms/block/tempate_filter';
     public const XML_NODE_ALLOWED_STREAM_WRAPPERS  = 'global/cms/allowed_stream_wrappers';
     public const XML_NODE_ALLOWED_MEDIA_EXT_SWF    = 'adminhtml/cms/browser/extensions/media_allowed/swf';
+    public const XML_PATH_USE_CMS_CANONICAL_TAG    = 'web/seo/cms_canonical_tag';
 
     protected $_moduleName = 'Mage_Cms';
 
@@ -68,4 +69,14 @@ public function isSwfDisabled()
     {
         return true;
     }
+
+    /**
+     * Check if <link rel="canonical"> can be used for CMS pages
+     *
+     * @param int|string|null|Mage_Core_Model_Store $store
+     */
+    public function canUseCanonicalTag($store = null): bool
+    {
+        return Mage::getStoreConfigFlag(self::XML_PATH_USE_CMS_CANONICAL_TAG, $store);
+    }
 }

app/code/core/Mage/Cms/etc/config.xml

@@ -182,6 +182,9 @@
     </global>
     <default>
         <web>
+            <seo>
+                <cms_canonical_tag>1</cms_canonical_tag>
+            </seo>
             <default>
                 <cms_home_page>home</cms_home_page>
                 <cms_no_route>no-route</cms_no_route>

app/code/core/Mage/Cms/etc/system.xml

@@ -51,6 +51,19 @@
                         </show_cms_breadcrumbs>
                     </fields>
                 </default>
+                <seo translate="label" module="cms">
+                    <fields>
+                        <cms_canonical_tag translate="label">
+                            <label>Use Canonical Link Meta Tag For CMS Pages</label>
+                            <frontend_type>select</frontend_type>
+                            <source_model>adminhtml/system_config_source_yesno</source_model>
+                            <sort_order>20</sort_order>
+                            <show_in_default>1</show_in_default>
+                            <show_in_website>1</show_in_website>
+                            <show_in_store>1</show_in_store>
+                        </cms_canonical_tag>
+                    </fields>
+                </seo>
             </groups>
         </web>
         <cms translate="label" module="cms">

app/locale/en_US/Mage_Cms.csv

@@ -98,6 +98,7 @@
 "Save Block","Save Block"
 "Save Page","Save Page"
 "Save Process","Save Process"
+"Search Engine Optimization","Search Engine Optimization"
 "Select Block...","Select Block..."
 "Select Page...","Select Page..."
 "Show Breadcrumbs for CMS Pages","Show Breadcrumbs for CMS Pages"
@@ -118,6 +119,7 @@
 "This block no longer exists.","This block no longer exists."
 "This page no longer exists.","This page no longer exists."
 "Title","Title"
+"Use Canonical Link Meta Tag For CMS Pages","Use Canonical Link Meta Tag For CMS Pages"
 "URL Key","URL Key"
 "Unable to find a block to delete.","Unable to find a block to delete."
 "Unable to find a page to delete.","Unable to find a page to delete."