NEW Add SubsiteState and initialisation middleware, replace Subsite::currentSubsiteID use

_config.php

@@ -1 +1,5 @@
 <?php
+
+use SilverStripe\Dev\Deprecation;
+
+Deprecation::notification_version('2.0', 'subsites');

_config/middleware.yml

@@ -0,0 +1,10 @@
+---
+Name: subsitesmiddleware
+After:
+  - requestprocessors
+---
+SilverStripe\Core\Injector\Injector:
+  SilverStripe\Control\Director:
+    properties:
+      Middlewares:
+        SubsitesStateMiddleware: %$SilverStripe\Subsites\Middleware\InitStateMiddleware

code/Middleware/InitStateMiddleware.php

@@ -0,0 +1,47 @@
+<?php
+
+namespace SilverStripe\Subsites\Middleware;
+
+use SilverStripe\Control\HTTPRequest;
+use SilverStripe\Control\Middleware\HTTPMiddleware;
+use SilverStripe\Core\Injector\Injector;
+use SilverStripe\Subsites\Model\Subsite;
+use SilverStripe\Subsites\State\SubsiteState;
+
+class InitStateMiddleware implements HTTPMiddleware
+{
+    public function process(HTTPRequest $request, callable $delegate)
+    {
+        $state = SubsiteState::create();
+        Injector::inst()->registerService($state);
+
+        $state->setSubsiteId($this->detectSubsiteId($request));
+
+        return $delegate($request);
+    }
+
+    /**
+     * Use the given request to detect the current subsite ID
+     *
+     * @param  HTTPRequest $request
+     * @return int
+     */
+    protected function detectSubsiteId(HTTPRequest $request)
+    {
+        $id = null;
+
+        if ($request->getVar('SubsiteID')) {
+            $id = (int) $request->getVar('SubsiteID');
+        }
+
+        if (Subsite::$use_session_subsiteid) {
+            $id = $request->getSession()->get('SubsiteID');
+        }
+
+        if ($id === null) {
+            $id = Subsite::getSubsiteIDForDomain();
+        }
+
+        return (int) $id;
+    }
+}

code/State/SubsiteState.php

@@ -0,0 +1,60 @@
+<?php
+
+namespace SilverStripe\Subsites\State;
+
+use SilverStripe\Core\Injector\Injectable;
+use SilverStripe\Core\Injector\Injector;
+
+/**
+ * SubsiteState provides static access to the current state for subsite related data during a request
+ */
+class SubsiteState
+{
+    use Injectable;
+
+    /**
+     * @var int|null
+     */
+    protected $subsiteId;
+
+    /**
+     * Get the current subsite ID
+     *
+     * @return int|null
+     */
+    public function getSubsiteId()
+    {
+        return $this->subsiteId;
+    }
+
+    /**
+     * Set the current subsite ID
+     *
+     * @param int $id
+     * @return $this
+     */
+    public function setSubsiteId($id)
+    {
+        $this->subsiteId = (int) $id;
+
+        return $this;
+    }
+
+    /**
+     * Perform a given action within the context of a new, isolated state. Modifications are temporary
+     * and the existing state will be restored afterwards.
+     *
+     * @param callable $callback Callback to run. Will be passed the nested state as a parameter
+     * @return mixed Result of callback
+     */
+    public function withState(callable $callback)
+    {
+        $newState = clone $this;
+        try {
+            Injector::inst()->registerService($newState);
+            return $callback($newState);
+        } finally {
+            Injector::inst()->registerService($this);
+        }
+    }
+}

code/extensions/CMSPageAddControllerExtension.php

@@ -3,14 +3,14 @@
 namespace SilverStripe\Subsites\Extensions;
 
 use SilverStripe\Core\Extension;
+use SilverStripe\Forms\FieldList;
 use SilverStripe\Forms\HiddenField;
-use SilverStripe\Subsites\Model\Subsite;
+use SilverStripe\Subsites\State\SubsiteState;
 
 class CMSPageAddControllerExtension extends Extension
 {
-
+    public function updatePageOptions(FieldList $fields)
-    public function updatePageOptions(&$fields)
     {
-        $fields->push(new HiddenField('SubsiteID', 'SubsiteID', Subsite::currentSubsiteID()));
+        $fields->push(HiddenField::create('SubsiteID', 'SubsiteID', SubsiteState::singleton()->getSubsiteId()));
     }
 }

code/extensions/FileSubsites.php

@@ -3,7 +3,6 @@
 namespace SilverStripe\Subsites\Extensions;
 
 use SilverStripe\Assets\Folder;
-use SilverStripe\Control\Session;
 use SilverStripe\Forms\DropdownField;
 use SilverStripe\Forms\FieldList;
 use SilverStripe\Forms\LiteralField;
@@ -12,6 +11,7 @@ use SilverStripe\ORM\DataQuery;
 use SilverStripe\ORM\Queries\SQLSelect;
 use SilverStripe\Security\Permission;
 use SilverStripe\Subsites\Model\Subsite;
+use SilverStripe\Subsites\State\SubsiteState;
 
 /**
  * Extension for the File object to add subsites support
@@ -96,7 +96,10 @@ class FileSubsites extends DataExtension
             return;
         }
 
-        $subsiteID = (int)Subsite::currentSubsiteID();
+        $subsiteID = SubsiteState::singleton()->getSubsiteId();
+        if ($subsiteID === null) {
+            return;
+        }
 
         // The foreach is an ugly way of getting the first key :-)
         foreach ($query->getFrom() as $tableName => $info) {
@@ -120,7 +123,7 @@ class FileSubsites extends DataExtension
             if (self::$default_root_folders_global) {
                 $this->owner->SubsiteID = 0;
             } else {
-                $this->owner->SubsiteID = Subsite::currentSubsiteID();
+                $this->owner->SubsiteID = SubsiteState::singleton()->getSubsiteId();
             }
         }
     }
@@ -131,7 +134,7 @@ class FileSubsites extends DataExtension
         if ($this->owner->Parent()) {
             $this->owner->SubsiteID = $this->owner->Parent()->SubsiteID;
         } else {
-            $this->owner->SubsiteID = Subsite::currentSubsiteID();
+            $this->owner->SubsiteID = SubsiteState::singleton()->getSubsiteId();
         }
         $this->owner->write();
     }
@@ -139,16 +142,16 @@ class FileSubsites extends DataExtension
     public function canEdit($member = null)
     {
         // Check the CMS_ACCESS_SecurityAdmin privileges on the subsite that owns this group
-        $subsiteID = Session::get('SubsiteID');
+        $subsiteID = SubsiteState::singleton()->getSubsiteId();
         if ($subsiteID && $subsiteID == $this->owner->SubsiteID) {
             return true;
         }
 
-        Session::set('SubsiteID', $this->owner->SubsiteID);
+        return SubsiteState::singleton()->withState(function ($newState) {
-        $access = Permission::check(['CMS_ACCESS_AssetAdmin', 'CMS_ACCESS_LeftAndMain']);
+            $newState->setSubsiteId($this->owner->SubsiteID);
-        Session::set('SubsiteID', $subsiteID);
 
-        return $access;
+            return Permission::check(['CMS_ACCESS_AssetAdmin', 'CMS_ACCESS_LeftAndMain']);
+        });
     }
 
     /**
@@ -158,6 +161,6 @@ class FileSubsites extends DataExtension
      */
     public function cacheKeyComponent()
     {
-        return 'subsite-' . Subsite::currentSubsiteID();
+        return 'subsite-' . SubsiteState::singleton()->getSubsiteId();
     }
 }

code/extensions/GroupSubsites.php

@@ -15,6 +15,7 @@ use SilverStripe\ORM\Queries\SQLSelect;
 use SilverStripe\Security\Group;
 use SilverStripe\Security\PermissionProvider;
 use SilverStripe\Subsites\Model\Subsite;
+use SilverStripe\Subsites\State\SubsiteState;
 
 /**
  * Extension for the Group object to add subsites support
@@ -154,10 +155,10 @@ class GroupSubsites extends DataExtension implements PermissionProvider
 
         // If you're querying by ID, ignore the sub-site - this is a bit ugly...
         if (!$query->filtersOnID()) {
-            /*if($context = DataObject::context_obj()) $subsiteID = (int)$context->SubsiteID;
+            $subsiteID = SubsiteState::singleton()->getSubsiteId();
-
+            if ($subsiteID === null) {
-            else */
+                return;
-            $subsiteID = (int)Subsite::currentSubsiteID();
+            }
 
             // Don't filter by Group_Subsites if we've already done that
             $hasGroupSubsites = false;
@@ -198,7 +199,7 @@ class GroupSubsites extends DataExtension implements PermissionProvider
     {
         // New record test approximated by checking whether the ID has changed.
         // Note also that the after write test is only used when we're *not* on a subsite
-        if ($this->owner->isChanged('ID') && !Subsite::currentSubsiteID()) {
+        if ($this->owner->isChanged('ID') && !SubsiteState::singleton()->getSubsiteId()) {
             $this->owner->AccessAllSubsites = 1;
         }
     }
@@ -207,7 +208,7 @@ class GroupSubsites extends DataExtension implements PermissionProvider
     {
         // New record test approximated by checking whether the ID has changed.
         // Note also that the after write test is only used when we're on a subsite
-        if ($this->owner->isChanged('ID') && $currentSubsiteID = Subsite::currentSubsiteID()) {
+        if ($this->owner->isChanged('ID') && $currentSubsiteID = SubsiteState::singleton()->getSubsiteId()) {
             $subsites = $this->owner->Subsites();
             $subsites->add($currentSubsiteID);
         }

code/extensions/LeftAndMainSubsites.php

@@ -3,12 +3,12 @@
 namespace SilverStripe\Subsites\Extensions;
 
 use SilverStripe\Admin\CMSMenu;
+use SilverStripe\Admin\LeftAndMainExtension;
 use SilverStripe\CMS\Model\SiteTree;
 use SilverStripe\Control\Controller;
-use SilverStripe\Control\Session;
 use SilverStripe\Core\Config\Config;
 use SilverStripe\Core\Convert;
-use SilverStripe\Core\Extension;
+use SilverStripe\Core\Manifest\ModuleLoader;
 use SilverStripe\Forms\HiddenField;
 use SilverStripe\ORM\ArrayList;
 use SilverStripe\ORM\DataObject;
@@ -17,6 +17,7 @@ use SilverStripe\Security\Permission;
 use SilverStripe\Security\Security;
 use SilverStripe\Subsites\Controller\SubsiteXHRController;
 use SilverStripe\Subsites\Model\Subsite;
+use SilverStripe\Subsites\State\SubsiteState;
 use SilverStripe\View\ArrayData;
 use SilverStripe\View\Requirements;
 
@@ -25,7 +26,7 @@ use SilverStripe\View\Requirements;
  *
  * @package subsites
  */
-class LeftAndMainSubsites extends Extension
+class LeftAndMainSubsites extends LeftAndMainExtension
 {
     private static $allowed_actions = ['CopyToSubsite'];
 
@@ -38,9 +39,11 @@ class LeftAndMainSubsites extends Extension
 
     public function init()
     {
-        Requirements::css('subsites/css/LeftAndMain_Subsites.css');
+        $module = ModuleLoader::getModule('silverstripe/subsites');
-        Requirements::javascript('subsites/javascript/LeftAndMain_Subsites.js');
+
-        Requirements::javascript('subsites/javascript/VirtualPage_Subsites.js');
+        Requirements::css($module->getRelativeResourcePath('css/LeftAndMain_Subsites.css'));
+        Requirements::javascript($module->getRelativeResourcePath('javascript/LeftAndMain_Subsites.js'));
+        Requirements::javascript($module->getRelativeResourcePath('javascript/VirtualPage_Subsites.js'));
     }
 
     /**
@@ -54,7 +57,7 @@ class LeftAndMainSubsites extends Extension
 
     public function updatePageOptions(&$fields)
     {
-        $fields->push(new HiddenField('SubsiteID', 'SubsiteID', Subsite::currentSubsiteID()));
+        $fields->push(HiddenField::create('SubsiteID', 'SubsiteID', SubsiteState::singleton()->getSubsiteId()));
     }
 
     /**
@@ -141,13 +144,14 @@ class LeftAndMainSubsites extends Extension
     public function ListSubsites()
     {
         $list = $this->Subsites();
-        $currentSubsiteID = Subsite::currentSubsiteID();
+        $currentSubsiteID = SubsiteState::singleton()->getSubsiteId();
 
         if ($list == null || $list->count() == 1 && $list->first()->DefaultSite == true) {
             return false;
         }
 
-        Requirements::javascript('subsites/javascript/LeftAndMain_Subsites.js');
+        $module = ModuleLoader::getModule('silverstripe/subsites');
+        Requirements::javascript($module->getRelativeResourcePath('javascript/LeftAndMain_Subsites.js'));
 
         $output = new ArrayList();
 
@@ -176,7 +180,7 @@ class LeftAndMainSubsites extends Extension
         }
 
         // Check subsite support.
-        if (Subsite::currentSubsiteID() == 0) {
+        if (SubsiteState::singleton()->getSubsiteId() == 0) {
             // Main site always supports everything.
             return true;
         }
@@ -194,9 +198,9 @@ class LeftAndMainSubsites extends Extension
 
     /**
      * Helper for testing if the subsite should be adjusted.
-     * @param $adminClass
+     * @param string $adminClass
-     * @param $recordSubsiteID
+     * @param int $recordSubsiteID
-     * @param $currentSubsiteID
+     * @param int $currentSubsiteID
      * @return bool
      */
     public function shouldChangeSubsite($adminClass, $recordSubsiteID, $currentSubsiteID)
@@ -227,7 +231,7 @@ class LeftAndMainSubsites extends Extension
 
         // Check if we have access to current section on the current subsite.
         $accessibleSites = $this->owner->sectionSites(true, 'Main site', $member);
-        return $accessibleSites->count() && $accessibleSites->find('ID', Subsite::currentSubsiteID());
+        return $accessibleSites->count() && $accessibleSites->find('ID', SubsiteState::singleton()->getSubsiteId());
     }
 
     /**
@@ -283,7 +287,11 @@ class LeftAndMainSubsites extends Extension
         if ($record
             && isset($record->SubsiteID, $this->owner->urlParams['ID'])
             && is_numeric($record->SubsiteID)
-            && $this->shouldChangeSubsite($this->owner->class, $record->SubsiteID, Subsite::currentSubsiteID())
+            && $this->shouldChangeSubsite(
+                $this->owner->class,
+                $record->SubsiteID,
+                SubsiteState::singleton()->getSubsiteId()
+            )
         ) {
             // Update current subsite in session
             Subsite::changeSubsite($record->SubsiteID);
@@ -306,7 +314,9 @@ class LeftAndMainSubsites extends Extension
             foreach ($menu as $candidate) {
                 if ($candidate->controller && $candidate->controller != $this->owner->class) {
                     $accessibleSites = singleton($candidate->controller)->sectionSites(true, 'Main site', $member);
-                    if ($accessibleSites->count() && $accessibleSites->find('ID', Subsite::currentSubsiteID())) {
+                    if ($accessibleSites->count()
+                        && $accessibleSites->find('ID', SubsiteState::singleton()->getSubsiteId())
+                    ) {
                         // Section is accessible, redirect there.
                         return $this->owner->redirect(singleton($candidate->controller)->Link());
                     }
@@ -334,7 +344,7 @@ class LeftAndMainSubsites extends Extension
 
     public function augmentNewSiteTreeItem(&$item)
     {
-        $item->SubsiteID = isset($_POST['SubsiteID']) ? $_POST['SubsiteID'] : Subsite::currentSubsiteID();
+        $item->SubsiteID = isset($_POST['SubsiteID']) ? $_POST['SubsiteID'] : SubsiteState::singleton()->getSubsiteId();
     }
 
     public function onAfterSave($record)

code/extensions/SiteConfigSubsites.php

@@ -9,6 +9,7 @@ use SilverStripe\ORM\DataQuery;
 use SilverStripe\ORM\Queries\SQLSelect;
 use SilverStripe\SiteConfig\SiteConfig;
 use SilverStripe\Subsites\Model\Subsite;
+use SilverStripe\Subsites\State\SubsiteState;
 
 /**
  * Extension for the SiteConfig object to add subsites support
@@ -41,7 +42,10 @@ class SiteConfigSubsites extends DataExtension
             }
         }
 
-        $subsiteID = (int)Subsite::currentSubsiteID();
+        $subsiteID = SubsiteState::singleton()->getSubsiteId();
+        if ($subsiteID === null) {
+            return;
+        }
 
         $froms = $query->getFrom();
         $froms = array_keys($froms);
@@ -55,7 +59,7 @@ class SiteConfigSubsites extends DataExtension
     public function onBeforeWrite()
     {
         if ((!is_numeric($this->owner->ID) || !$this->owner->ID) && !$this->owner->SubsiteID) {
-            $this->owner->SubsiteID = Subsite::currentSubsiteID();
+            $this->owner->SubsiteID = SubsiteState::singleton()->getSubsiteId();
         }
     }
 
@@ -64,11 +68,11 @@ class SiteConfigSubsites extends DataExtension
      */
     public function cacheKeyComponent()
     {
-        return 'subsite-' . Subsite::currentSubsiteID();
+        return 'subsite-' . SubsiteState::singleton()->getSubsiteId();
     }
 
     public function updateCMSFields(FieldList $fields)
     {
-        $fields->push(new HiddenField('SubsiteID', 'SubsiteID', Subsite::currentSubsiteID()));
+        $fields->push(HiddenField::create('SubsiteID', 'SubsiteID', SubsiteState::singleton()->getSubsiteId()));
     }
 }

code/extensions/SiteTreeSubsites.php

@@ -2,6 +2,7 @@
 
 namespace SilverStripe\Subsites\Extensions;
 
+use Page;
 use SilverStripe\CMS\Model\SiteTree;
 use SilverStripe\Control\Controller;
 use SilverStripe\Control\Director;
@@ -20,6 +21,7 @@ use SilverStripe\ORM\Queries\SQLSelect;
 use SilverStripe\Security\Member;
 use SilverStripe\SiteConfig\SiteConfig;
 use SilverStripe\Subsites\Model\Subsite;
+use SilverStripe\Subsites\State\SubsiteState;
 use SilverStripe\View\SSViewer;
 
 /**
@@ -64,12 +66,15 @@ class SiteTreeSubsites extends DataExtension
             return;
         }
 
+        $subsiteID = null;
         if (Subsite::$force_subsite) {
             $subsiteID = Subsite::$force_subsite;
         } else {
-            /*if($context = DataObject::context_obj()) $subsiteID = (int)$context->SubsiteID;
+            $subsiteID = SubsiteState::singleton()->getSubsiteId();
-            else */
+        }
-            $subsiteID = (int)Subsite::currentSubsiteID();
+
+        if ($subsiteID === null) {
+            return;
         }
 
         // The foreach is an ugly way of getting the first key :-)
@@ -87,7 +92,7 @@ class SiteTreeSubsites extends DataExtension
     public function onBeforeWrite()
     {
         if (!$this->owner->ID && !$this->owner->SubsiteID) {
-            $this->owner->SubsiteID = Subsite::currentSubsiteID();
+            $this->owner->SubsiteID = SubsiteState::singleton()->getSubsiteId();
         }
 
         parent::onBeforeWrite();
@@ -128,7 +133,7 @@ class SiteTreeSubsites extends DataExtension
                 )->setHeadingLevel(4)
             );
 
-
+            // @todo check if this needs re-implementation
 //            $copyAction->includeDefaultJS(false);
         }
 
@@ -163,7 +168,7 @@ class SiteTreeSubsites extends DataExtension
             $subsiteID = $subsiteID->ID;
         }
 
-        $oldSubsite = Subsite::currentSubsiteID();
+        $oldSubsite = SubsiteState::singleton()->getSubsiteId();
         if ($subsiteID) {
             Subsite::changeSubsite($subsiteID);
         } else {
@@ -276,7 +281,7 @@ class SiteTreeSubsites extends DataExtension
             //
             // We do the second best: fetch the likely SubsiteID from the session. The drawback is this might
             // make it possible to force relations to point to other (forbidden) subsites.
-            $subsiteID = Subsite::currentSubsiteID();
+            $subsiteID = SubsiteState::singleton()->getSubsiteId();
         }
 
         // Return true if they have access to this object's site
@@ -427,7 +432,7 @@ class SiteTreeSubsites extends DataExtension
     public function augmentValidURLSegment()
     {
         // If this page is being filtered in the current subsite, then no custom validation query is required.
-        $subsite = Subsite::$force_subsite ?: Subsite::currentSubsiteID();
+        $subsite = Subsite::$force_subsite ?: SubsiteState::singleton()->getSubsiteId();
         if (empty($this->owner->SubsiteID) || $subsite == $this->owner->SubsiteID) {
             return null;
         }
@@ -450,7 +455,7 @@ class SiteTreeSubsites extends DataExtension
      */
     public function cacheKeyComponent()
     {
-        return 'subsite-' . Subsite::currentSubsiteID();
+        return 'subsite-' . SubsiteState::singleton()->getSubsiteId();
     }
 
     /**

code/model/Subsite.php

@@ -4,7 +4,6 @@ namespace SilverStripe\Subsites\Model;
 
 use SilverStripe\Admin\CMSMenu;
 use SilverStripe\CMS\Model\SiteTree;
-use SilverStripe\Control\Controller;
 use SilverStripe\Control\Director;
 use SilverStripe\Control\Session;
 use SilverStripe\Core\Convert;
@@ -32,6 +31,7 @@ use SilverStripe\ORM\SS_List;
 use SilverStripe\Security\Group;
 use SilverStripe\Security\Member;
 use SilverStripe\Security\Permission;
+use SilverStripe\Subsites\State\SubsiteState;
 use SilverStripe\Versioned\Versioned;
 use UnexpectedValueException;
 
@@ -132,7 +132,7 @@ class Subsite extends DataObject
      */
     public static function currentSubsite()
     {
-        return Subsite::get()->byID(self::currentSubsiteID());
+        return Subsite::get()->byID(SubsiteState::singleton()->getSubsiteId());
     }
 
     /**
@@ -143,25 +143,14 @@ class Subsite extends DataObject
      *
      * You can simulate subsite access without creating virtual hosts by appending ?SubsiteID=<ID> to the request.
      *
-     * @todo Pass $request object from controller so we don't have to rely on $_GET
-     *
      * @return int ID of the current subsite instance
+     *
+     * @deprecated 2.0..3.0 Use SubsiteState::singleton()->getSubsiteId() instead
      */
     public static function currentSubsiteID()
     {
-        $id = null;
+        Deprecation::notice('3.0', 'Use SubsiteState::singleton()->getSubsiteId() instead');
-
+        return SubsiteState::singleton()->getSubsiteId();
-        if (isset($_GET['SubsiteID'])) {
-            $id = (int)$_GET['SubsiteID'];
-        } elseif (Subsite::$use_session_subsiteid) {
-            $id = Controller::curr()->getRequest()->getSession()->get('SubsiteID');
-        }
-
-        if ($id === null) {
-            $id = self::getSubsiteIDForDomain();
-        }
-
-        return (int)$id;
     }
 
     /**
@@ -184,7 +173,7 @@ class Subsite extends DataObject
             $subsiteID = $subsite;
         }
 
-        Controller::curr()->getRequest()->getSession()->set('SubsiteID', (int)$subsiteID);
+        SubsiteState::singleton()->setSubsiteId($subsiteID);
 
         // Set locale
         if (is_object($subsite) && $subsite->Language !== '') {
@@ -940,7 +929,7 @@ JS;
     {
         $duplicate = parent::duplicate($doWrite);
 
-        $oldSubsiteID = Session::get('SubsiteID');
+        $oldSubsiteID = SubsiteState::singleton()->getSubsiteId();
         self::changeSubsite($this->ID);
 
         /*

tests/php/LeftAndMainSubsitesTest.php

@@ -10,6 +10,7 @@ use SilverStripe\Core\Config\Config;
 use SilverStripe\Dev\FunctionalTest;
 use SilverStripe\Security\Member;
 use SilverStripe\Subsites\Model\Subsite;
+use SilverStripe\Subsites\State\SubsiteState;
 
 class LeftAndMainSubsitesTest extends FunctionalTest
 {
@@ -24,7 +25,7 @@ class LeftAndMainSubsitesTest extends FunctionalTest
     protected function objFromFixture($className, $identifier)
     {
         Subsite::disable_subsite_filter(true);
-        $obj = parent::objFromFixture($classname, $identifier);
+        $obj = parent::objFromFixture($className, $identifier);
         Subsite::disable_subsite_filter(false);
 
         return $obj;
@@ -71,13 +72,13 @@ class LeftAndMainSubsitesTest extends FunctionalTest
 
         foreach ($ids as $id) {
             Subsite::changeSubsite($id);
-            $this->assertEquals($id, Subsite::currentSubsiteID());
+            $this->assertEquals($id, SubsiteState::singleton()->getSubsiteId());
 
             $left = new LeftAndMain();
             $this->assertTrue($left->canView(), "Admin user can view subsites LeftAndMain with id = '$id'");
             $this->assertEquals(
                 $id,
-                Subsite::currentSubsiteID(),
+                SubsiteState::singleton()->getSubsiteId(),
                 'The current subsite has not been changed in the process of checking permissions for admin user.'
             );
         }
@@ -86,7 +87,6 @@ class LeftAndMainSubsitesTest extends FunctionalTest
     public function testShouldChangeSubsite()
     {
         $l = new LeftAndMain();
-        Config::nest();
 
         Config::modify()->set(CMSPageEditController::class, 'treats_subsite_0_as_global', false);
         $this->assertTrue($l->shouldChangeSubsite(CMSPageEditController::class, 0, 5));
@@ -99,7 +99,5 @@ class LeftAndMainSubsitesTest extends FunctionalTest
         $this->assertFalse($l->shouldChangeSubsite(CMSPageEditController::class, 0, 0));
         $this->assertTrue($l->shouldChangeSubsite(CMSPageEditController::class, 1, 5));
         $this->assertFalse($l->shouldChangeSubsite(CMSPageEditController::class, 1, 1));
-
-        Config::unnest();
     }
 }

tests/php/SiteTreeSubsitesTest.php

@@ -8,7 +8,6 @@ use SilverStripe\CMS\Controllers\ModelAsController;
 use SilverStripe\ErrorPage\ErrorPage;
 use SilverStripe\CMS\Model\SiteTree;
 use SilverStripe\Control\Director;
-use SilverStripe\Control\Session;
 use SilverStripe\Core\Config\Config;
 use SilverStripe\Core\Convert;
 use SilverStripe\Forms\FieldList;
@@ -107,7 +106,8 @@ class SiteTreeSubsitesTest extends BaseSubsiteTest
         $subsite2 = $this->objFromFixture(Subsite::class, 'subsite2');
 
         // Cant pass member as arguments to canEdit() because of GroupSubsites
-        Session::set('loggedInAs', $admin->ID);
+        $this->logInAs($admin);
+
         $this->assertTrue(
             (bool)$subsite1page->canEdit(),
             'Administrators can edit all subsites'
@@ -116,13 +116,13 @@ class SiteTreeSubsitesTest extends BaseSubsiteTest
         // @todo: Workaround because GroupSubsites->augmentSQL() is relying on session state
         Subsite::changeSubsite($subsite1);
 
-        Session::set('loggedInAs', $subsite1member->ID);
+        $this->logInAs($subsite1member->ID);
         $this->assertTrue(
             (bool)$subsite1page->canEdit(),
             'Members can edit pages on a subsite if they are in a group belonging to this subsite'
         );
 
-        Session::set('loggedInAs', $subsite2member->ID);
+        $this->logInAs($subsite2member->ID);
         $this->assertFalse(
             (bool)$subsite1page->canEdit(),
             'Members cant edit pages on a subsite if they are not in a group belonging to this subsite'
@@ -169,8 +169,7 @@ class SiteTreeSubsitesTest extends BaseSubsiteTest
 
     public function testPageTypesBlacklistInClassDropdown()
     {
-        $editor = $this->objFromFixture(Member::class, 'editor');
+        $this->logInAs('editor');
-        Session::set('loggedInAs', $editor->ID);
 
         $s1 = $this->objFromFixture(Subsite::class, 'domaintest1');
         $s2 = $this->objFromFixture(Subsite::class, 'domaintest2');
@@ -241,8 +240,7 @@ class SiteTreeSubsitesTest extends BaseSubsiteTest
 
     public function testPageTypesBlacklistInCMSMain()
     {
-        $editor = $this->objFromFixture(Member::class, 'editor');
+        $this->logInAs('editor');
-        Session::set('loggedInAs', $editor->ID);
 
         $cmsmain = new CMSMain();
 

tests/php/SubsiteAdminFunctionalTest.php

@@ -3,12 +3,11 @@
 namespace SilverStripe\Subsites\Tests;
 
 use SilverStripe\CMS\Controllers\CMSPageEditController;
-use SilverStripe\Control\Session;
 use SilverStripe\Core\Config\Config;
 use SilverStripe\Dev\FunctionalTest;
-use SilverStripe\Security\Member;
 use SilverStripe\Subsites\Controller\SubsiteXHRController;
 use SilverStripe\Subsites\Model\Subsite;
+use SilverStripe\Subsites\State\SubsiteState;
 
 class SubsiteAdminFunctionalTest extends FunctionalTest
 {
@@ -61,12 +60,12 @@ class SubsiteAdminFunctionalTest extends FunctionalTest
         $this->logInAs('admin');
 
         $this->getAndFollowAll('admin/pages/?SubsiteID=0');
-        $this->assertEquals(Subsite::currentSubsiteID(), '0', 'Can access main site.');
+        $this->assertEquals(SubsiteState::singleton()->getSubsiteId(), '0', 'Can access main site.');
         $this->assertRegExp('#^admin/pages.*#', $this->mainSession->lastUrl(), 'Lands on the correct section');
 
         $subsite1 = $this->objFromFixture(Subsite::class, 'subsite1');
         $this->getAndFollowAll("admin/pages/?SubsiteID={$subsite1->ID}");
-        $this->assertEquals(Subsite::currentSubsiteID(), $subsite1->ID, 'Can access other subsite.');
+        $this->assertEquals(SubsiteState::singleton()->getSubsiteId(), $subsite1->ID, 'Can access other subsite.');
         $this->assertRegExp('#^admin/pages.*#', $this->mainSession->lastUrl(), 'Lands on the correct section');
 
         $response = $this->getAndFollowAll(SubsiteXHRController::class);
@@ -90,7 +89,7 @@ class SubsiteAdminFunctionalTest extends FunctionalTest
         Subsite::changeSubsite(0);
         $this->getAndFollowAll("admin/pages/edit/show/$subsite1Home->ID");
         $this->assertEquals(
-            Subsite::currentSubsiteID(),
+            SubsiteState::singleton()->getSubsiteId(),
             $subsite1Home->SubsiteID,
             'Loading an object switches the subsite'
         );
@@ -100,7 +99,7 @@ class SubsiteAdminFunctionalTest extends FunctionalTest
         Subsite::changeSubsite(0);
         $this->getAndFollowAll("admin/pages/edit/show/$subsite1Home->ID");
         $this->assertEquals(
-            Subsite::currentSubsiteID(),
+            SubsiteState::singleton()->getSubsiteId(),
             $subsite1Home->SubsiteID,
             'Loading a non-main-site object still switches the subsite if configured with treats_subsite_0_as_global'
         );
@@ -108,7 +107,7 @@ class SubsiteAdminFunctionalTest extends FunctionalTest
 
         $this->getAndFollowAll("admin/pages/edit/show/$mainSubsitePage->ID");
         $this->assertNotEquals(
-            Subsite::currentSubsiteID(),
+            SubsiteState::singleton()->getSubsiteId(),
             $mainSubsitePage->SubsiteID,
             'Loading a main-site object does not change the subsite if configured with treats_subsite_0_as_global'
         );
@@ -126,12 +125,12 @@ class SubsiteAdminFunctionalTest extends FunctionalTest
         $this->logInAs('editor');
 
         $this->getAndFollowAll('admin/pages/?SubsiteID=0');
-        $this->assertEquals(Subsite::currentSubsiteID(), '0', 'Can access main site.');
+        $this->assertEquals(SubsiteState::singleton()->getSubsiteId(), '0', 'Can access main site.');
         $this->assertRegExp('#^admin/pages.*#', $this->mainSession->lastUrl(), 'Lands on the correct section');
 
         $subsite1 = $this->objFromFixture(Subsite::class, 'subsite1');
         $this->getAndFollowAll("admin/pages/?SubsiteID={$subsite1->ID}");
-        $this->assertEquals(Subsite::currentSubsiteID(), $subsite1->ID, 'Can access other subsite.');
+        $this->assertEquals(SubsiteState::singleton()->getSubsiteId(), $subsite1->ID, 'Can access other subsite.');
         $this->assertRegExp('#^admin/pages.*#', $this->mainSession->lastUrl(), 'Lands on the correct section');
 
         $response = $this->getAndFollowAll('SubsiteXHRController');
@@ -147,19 +146,18 @@ class SubsiteAdminFunctionalTest extends FunctionalTest
      */
     public function testSubsiteAdmin()
     {
-        $member = $this->objFromFixture(Member::class, 'subsite1member');
+        $this->logInAs('subsite1member');
-        Session::set('loggedInAs', $member->ID);
 
         $subsite1 = $this->objFromFixture(Subsite::class, 'subsite1');
 
         // Check allowed URL.
         $this->getAndFollowAll("admin/pages/?SubsiteID={$subsite1->ID}");
-        $this->assertEquals(Subsite::currentSubsiteID(), $subsite1->ID, 'Can access own subsite.');
+        $this->assertEquals(SubsiteState::singleton()->getSubsiteId(), $subsite1->ID, 'Can access own subsite.');
         $this->assertRegExp('#^admin/pages.*#', $this->mainSession->lastUrl(), 'Can access permitted section.');
 
         // Check forbidden section in allowed subsite.
         $this->getAndFollowAll("admin/assets/?SubsiteID={$subsite1->ID}");
-        $this->assertEquals(Subsite::currentSubsiteID(), $subsite1->ID, 'Is redirected within subsite.');
+        $this->assertEquals(SubsiteState::singleton()->getSubsiteId(), $subsite1->ID, 'Is redirected within subsite.');
         $this->assertNotRegExp(
             '#^admin/assets/.*#',
             $this->mainSession->lastUrl(),
@@ -168,11 +166,11 @@ class SubsiteAdminFunctionalTest extends FunctionalTest
 
         // Check forbidden site, on a section that's allowed on another subsite
         $this->getAndFollowAll('admin/pages/?SubsiteID=0');
-        $this->assertEquals(Subsite::currentSubsiteID(), $subsite1->ID, 'Is redirected to permitted subsite.');
+        $this->assertEquals(SubsiteState::singleton()->getSubsiteId(), $subsite1->ID, 'Is redirected to permitted subsite.');
 
         // Check forbidden site, on a section that's not allowed on any other subsite
         $this->getAndFollowAll('admin/assets/?SubsiteID=0');
-        $this->assertEquals(Subsite::currentSubsiteID(), $subsite1->ID, 'Is redirected to first permitted subsite.');
+        $this->assertEquals(SubsiteState::singleton()->getSubsiteId(), $subsite1->ID, 'Is redirected to first permitted subsite.');
         $this->assertNotRegExp('#^Security/login.*#', $this->mainSession->lastUrl(), 'Is not denied access');
 
         // Check the standalone XHR controller.

tests/php/SubsiteFunctionalTest.php

@@ -1,6 +1,6 @@
 <?php
 
-namespace subsites\tests\php;
+namespace SilverStripe\Subsites\Tests;
 
 use Page;
 use SilverStripe\Dev\FunctionalTest;
@@ -22,7 +22,7 @@ class SubsiteFunctionalTest extends FunctionalTest
 
         $subsitePage = $this->objFromFixture(Page::class, 'contact');
         $this->get($subsitePage->AbsoluteLink());
-        $this->assertEquals($subsitePage->SubsiteID, Subsite::currentSubsiteID(), 'Subsite should be changed');
+        $this->assertEquals($subsitePage->SubsiteID, SubsiteState::singleton()->getSubsiteId(), 'Subsite should be changed');
         $this->assertEquals(
             SSViewer::get_themes(),
             $defaultThemes,
@@ -32,7 +32,7 @@ class SubsiteFunctionalTest extends FunctionalTest
         $pageWithTheme = $this->objFromFixture(Page::class, 'subsite1_contactus');
         $this->get($pageWithTheme->AbsoluteLink());
         $subsiteTheme = $pageWithTheme->Subsite()->Theme;
-        $this->assertEquals($pageWithTheme->SubsiteID, Subsite::currentSubsiteID(), 'Subsite should be changed');
+        $this->assertEquals($pageWithTheme->SubsiteID, SubsiteState::singleton()->getSubsiteId(), 'Subsite should be changed');
         $this->assertEquals(
             SSViewer::get_themes(),
             array_merge([$subsiteTheme], $defaultThemes),

tests/php/SubsiteTest.php

@@ -10,6 +10,8 @@ use SilverStripe\ORM\DataObject;
 use SilverStripe\Security\Member;
 use SilverStripe\Subsites\Model\Subsite;
 use SilverStripe\Subsites\Model\SubsiteDomain;
+use SilverStripe\Subsites\State\SubsiteState;
+use UnexpectedValueException;
 
 class SubsiteTest extends BaseSubsiteTest
 {
@@ -59,7 +61,7 @@ class SubsiteTest extends BaseSubsiteTest
 
         // Test that changeSubsite is working
         Subsite::changeSubsite($template->ID);
-        $this->assertEquals($template->ID, Subsite::currentSubsiteID());
+        $this->assertEquals($template->ID, SubsiteState::singleton()->getSubsiteId());
         $tmplStaff = $this->objFromFixture('Page', 'staff');
         $tmplHome = DataObject::get_one('Page', "\"URLSegment\" = 'home'");