BUG Move the SubsiteList PJAX request to a dedicated Controller.

Currently the request cannot be made if one doesn't have access to the
SubsiteAdmin section, which often happens with subsite-specific admins.

code/SubsiteAdmin.php

@@ -30,17 +30,4 @@ class SubsiteAdmin extends ModelAdmin {
 		return $form;
 	}
 
-	public function getResponseNegotiator() {
-		$negotiator = parent::getResponseNegotiator();
-		$self = $this;
-		// Register a new callback
-		$negotiator->setCallback('SubsiteList', function() use(&$self) {
-			return $self->SubsiteList();
-		});
-		return $negotiator;
-	}
-
-	public function SubsiteList() {
-		return $this->renderWith('SubsiteList');
-	}
 }

code/SubsiteXHRController.php

@@ -0,0 +1,38 @@
+<?php
+
+/**
+ * Section-agnostic PJAX controller.
+ */
+class SubsiteXHRController extends LeftAndMain {
+
+	/**
+	 * Relax the access permissions, so anyone who has access to any CMS subsite can access this controller.
+	 */
+	public function canView($member = null) {
+		if (parent::canView()) return true;
+
+		if (Subsite::all_accessible_sites()->count()>0) return true;
+
+		return false;
+	}
+
+	public function getResponseNegotiator() {
+		$negotiator = parent::getResponseNegotiator();
+		$self = $this;
+
+		// Register a new callback
+		$negotiator->setCallback('SubsiteList', function() use(&$self) {
+			return $self->SubsiteList();
+		});
+
+		return $negotiator;
+	}
+
+	/**
+	 * Provide the list of available subsites as a cms-section-agnostic PJAX handler.
+	 */
+	public function SubsiteList() {
+		return $this->renderWith('SubsiteList');
+	}
+
+}

javascript/LeftAndMain_Subsites.js

@@ -58,7 +58,7 @@
 		 */
 		$('.cms-container .cms-menu-list li a').entwine({
 			onclick: function(e) {
-				$('.cms-container').subsiteFetchPjaxFragment('admin/subsites/', 'SubsiteList');
+				$('.cms-container').subsiteFetchPjaxFragment('SubsiteXHRController', 'SubsiteList');
 				this._super(e);
 			}
 		});
@@ -68,7 +68,7 @@
 		 */
 		$('.cms-container .SubsiteAdmin .cms-edit-form fieldset.ss-gridfield').entwine({
 			onreload: function(e) {
-				$('.cms-container').subsiteFetchPjaxFragment('admin/subsites/', 'SubsiteList');
+				$('.cms-container').subsiteFetchPjaxFragment('SubsiteXHRController', 'SubsiteList');
 				this._super(e);
 			}
 		});
@@ -81,7 +81,7 @@
 		 */
 		$('.cms-container .cms-content-fields .subsite-model').entwine({
 			onadd: function(e) {
-				$('.cms-container').subsiteFetchPjaxFragment('admin/subsites/', 'SubsiteList');
+				$('.cms-container').subsiteFetchPjaxFragment('SubsiteXHRController', 'SubsiteList');
 				this._super(e);
 			}
 		});