API Make SubsiteXHRController a subclass of AdminController

src/Controller/SubsiteXHRController.php

@@ -2,20 +2,25 @@
 
 namespace SilverStripe\Subsites\Controller;
 
-use SilverStripe\Admin\LeftAndMain;
+use SilverStripe\Admin\AdminController;
+use SilverStripe\Control\HTTPRequest;
+use SilverStripe\Control\HTTPResponse;
 use SilverStripe\Control\PjaxResponseNegotiator;
+use SilverStripe\ORM\FieldType\DBHTMLText;
 use SilverStripe\Security\Member;
-use SilverStripe\Security\Permission;
 use SilverStripe\Subsites\Model\Subsite;
 
 /**
- * Section-agnostic PJAX controller.
+ * Section-agnostic PJAX controller that renders the subsites swapper dropdown
  */
-class SubsiteXHRController extends LeftAndMain
+class SubsiteXHRController extends AdminController
 {
     private static $url_segment = 'subsite_xhr';
 
-    private static $ignore_menuitem = true;
+    public function index(HTTPRequest $request): HTTPResponse
+    {
+        return $this->getResponseNegotiator()->respond($request);
+    }
 
     /**
      * Relax the access permissions, so anyone who has access to any CMS subsite can access this controller.
@@ -36,33 +41,21 @@ public function canView($member = null)
     }
 
     /**
-     * Allow access if user allowed into the CMS at all.
+     * Get a Pjax response negotiator for the subsite list
      */
-    public function canAccess()
-    {
-        // Allow if any cms access is available
-        return Permission::check([
-            'CMS_ACCESS', // Supported by 3.1.14 and up
-            'CMS_ACCESS_LeftAndMain'
-        ]);
-    }
-
     public function getResponseNegotiator(): PjaxResponseNegotiator
     {
-        $negotiator = parent::getResponseNegotiator();
-
-        // Register a new callback
-        $negotiator->setCallback('SubsiteList', function () {
-            return $this->SubsiteList();
-        });
-
-        return $negotiator;
+        return new PjaxResponseNegotiator([
+            'SubsiteList' => function () {
+                return $this->SubsiteList();
+            },
+        ]);
     }
 
     /**
      * Provide the list of available subsites as a cms-section-agnostic PJAX handler.
      */
-    public function SubsiteList()
+    public function SubsiteList(): DBHTMLText
     {
         return $this->renderWith(['type' => 'Includes', SubsiteXHRController::class . '_subsitelist']);
     }

src/Extensions/LeftAndMainSubsites.php

@@ -23,12 +23,14 @@
 use SilverStripe\Subsites\Model\Subsite;
 use SilverStripe\Subsites\State\SubsiteState;
 use SilverStripe\Model\ArrayData;
+use SilverStripe\Model\List\SS_List;
 use SilverStripe\View\Requirements;
+use SilverStripe\View\TemplateGlobalProvider;
 
 /**
  * Decorator designed to add subsites support to LeftAndMain
  */
-class LeftAndMainSubsites extends Extension
+class LeftAndMainSubsites extends Extension implements TemplateGlobalProvider
 {
     private static $allowed_actions = ['CopyToSubsite'];
 
@@ -45,6 +47,42 @@ protected function onInit()
         Requirements::javascript('silverstripe/subsites:client/dist/js/LeftAndMain_Subsites.js');
     }
 
+    public static function get_template_global_variables()
+    {
+        return [
+            'SubsiteSwitchList',
+        ];
+    }
+
+    /**
+     * Generates a list of subsites with the data needed to
+     * produce a dropdown site switcher
+     * @return SS_List<Subsite>
+     */
+    public static function SubsiteSwitchList(): SS_List
+    {
+        $list = Subsite::all_accessible_sites();
+        $currentSubsiteID = SubsiteState::singleton()->getSubsiteId();
+
+        if ($list == null || $list->count() == 1 && $list->first()->DefaultSite == true) {
+            return false;
+        }
+
+        $output = ArrayList::create();
+
+        foreach ($list as $subsite) {
+            $currentState = $subsite->ID == $currentSubsiteID ? 'selected' : '';
+
+            $output->push(ArrayData::create([
+                'CurrentState' => $currentState,
+                'ID' => $subsite->ID,
+                'Title' => $subsite->Title,
+            ]));
+        }
+
+        return $output;
+    }
+
     /**
      * Set the title of the CMS tree
      */
@@ -139,37 +177,6 @@ public function Subsites()
         return Subsite::all_accessible_sites();
     }
 
-    /**
-     * Generates a list of subsites with the data needed to
-     * produce a dropdown site switcher
-     * @return ArrayList<Subsite>
-     */
-    public function ListSubsites()
-    {
-        $list = $this->Subsites();
-        $currentSubsiteID = SubsiteState::singleton()->getSubsiteId();
-
-        if ($list == null || $list->count() == 1 && $list->first()->DefaultSite == true) {
-            return false;
-        }
-
-        Requirements::javascript('silverstripe/subsites:client/dist/js/LeftAndMain_Subsites.js');
-
-        $output = ArrayList::create();
-
-        foreach ($list as $subsite) {
-            $currentState = $subsite->ID == $currentSubsiteID ? 'selected' : '';
-
-            $output->push(ArrayData::create([
-                'CurrentState' => $currentState,
-                'ID' => $subsite->ID,
-                'Title' => $subsite->Title,
-            ]));
-        }
-
-        return $output;
-    }
-
     public function alternateMenuDisplayCheck($controllerName)
     {
         if (!class_exists($controllerName ?? '')) {

templates/SilverStripe/Admin/LeftAndMain_Menu.ss

@@ -5,7 +5,8 @@
         <% include SilverStripe\\Admin\\LeftAndMain_MenuLogo %>
         <% include SilverStripe\\Admin\\LeftAndMain_MenuStatus %>
 
-        <% if $ListSubsites.Count > 1 %>
+        <% if $SubsiteSwitchList.Count > 1 %>
+            <% require javascript('silverstripe/subsites:client/dist/js/LeftAndMain_Subsites.js') %>
             <% include SilverStripe\\Subsites\\Controller\\SubsiteXHRController_subsitelist %>
         <% end_if %>
     </div>

templates/SilverStripe/Subsites/Controller/Includes/SubsiteXHRController_subsitelist.ss

@@ -1,7 +1,7 @@
 <div class="cms-subsites" data-pjax-fragment="SubsiteList">
 	<div class="field dropdown">
 		<select id="SubsitesSelect">
-			<% loop $ListSubsites %>
+			<% loop $SubsiteSwitchList %>
 				<option value="$ID" $CurrentState>$Title</option>
 			<% end_loop %>
 		</select>