Session GridField state manager

src/Forms/GridField/GridFieldDetailForm_ItemRequest.php

@@ -454,6 +454,13 @@ protected function getFormActions()
 
             $gridState = $this->gridField->getState(false);
             $actions->push(HiddenField::create($manager->getStateKey($this->gridField), null, $gridState));
+            if (ClassInfo::hasMethod($manager, 'getStateRequestVar')) {
+                $stateRequestVar = $manager->getStateRequestVar();
+                $stateValue = $this->getRequest()->requestVar($stateRequestVar);
+                if ($stateValue) {
+                    $actions->push(HiddenField::create($stateRequestVar, '', $stateValue));
+                }
+            }
 
             $actions->push($this->getRightGroupField());
         } else { // adding new record

src/Forms/GridField/GridState.php

@@ -85,7 +85,7 @@ private function mergeValues(GridState_Data $data, array $array): void
     public function getData()
     {
         if (!$this->data) {
-            $this->data = new GridState_Data();
+            $this->data = new GridState_Data([], $this);
         }
 
         return $this->data;
@@ -99,6 +99,11 @@ public function getList()
         return $this->grid->getList();
     }
 
+    public function getGridField(): GridField
+    {
+        return $this->grid;
+    }
+
     /**
      * Returns a json encoded string representation of this state.
      *

src/Forms/GridField/GridState_Data.php

@@ -2,6 +2,8 @@
 
 namespace SilverStripe\Forms\GridField;
 
+use SilverStripe\Core\ClassInfo;
+
 /**
  * Simple set of data, similar to stdClass, but without the notice-level
  * errors.
@@ -10,29 +12,33 @@
  */
 class GridState_Data
 {
+    use GridFieldStateAware;
 
     /**
      * @var array
      */
     protected $data;
 
+    protected ?GridState $state;
+
     protected $defaults = [];
 
-    public function __construct($data = [])
+    public function __construct($data = [], ?GridState $state = null)
     {
         $this->data = $data;
+        $this->state = $state;
     }
 
     public function __get($name)
     {
-        return $this->getData($name, new GridState_Data());
+        return $this->getData($name, new GridState_Data([], $this->state));
     }
 
     public function __call($name, $arguments)
     {
         // Assume first parameter is default value
         if (empty($arguments)) {
-            $default = new GridState_Data();
+            $default = new GridState_Data([], $this->state);
         } else {
             $default = $arguments[0];
         }
@@ -72,16 +78,25 @@ public function getData($name, $default = null)
             $this->data[$name] = $default;
         } else {
             if (is_array($this->data[$name])) {
-                $this->data[$name] = new GridState_Data($this->data[$name]);
+                $this->data[$name] = new GridState_Data($this->data[$name], $this->state);
             }
         }
 
         return $this->data[$name];
     }
 
+    public function storeData()
+    {
+        $stateManager = $this->getStateManager();
+        if (ClassInfo::hasMethod($stateManager, 'storeState') && $this->state) {
+            $stateManager->storeState($this->state->getGridField(), $this->state->Value());
+        }
+    }
+
     public function __set($name, $value)
     {
         $this->data[$name] = $value;
+        $this->storeData();
     }
 
     public function __isset($name)
@@ -92,6 +107,7 @@ public function __isset($name)
     public function __unset($name)
     {
         unset($this->data[$name]);
+        $this->storeData();
     }
 
     public function __toString()

src/Forms/GridField/SessionGridFieldStateManager.php

@@ -0,0 +1,101 @@
+<?php
+
+namespace SilverStripe\Forms\GridField;
+
+use SilverStripe\Control\Controller;
+use SilverStripe\Control\HTTPRequest;
+
+/**
+ * Creates a unique key for managing GridField states in user Session, for both storage and retrieval.
+ * Only stores states and generates a session key if a state is requested to be stored
+ * (i.e. the state is changed from the default).
+ * If a session state key is present in the request, it will always be used instead of generating a new one.
+ */
+class SessionGridFieldStateManager implements GridFieldStateManagerInterface
+{
+    protected static $state_ids = [];
+
+    protected function getStateID(GridField $gridField, $create = false): ?string
+    {
+        $requestVar = $this->getStateRequestVar();
+        $sessionStateID = $gridField->getForm()?->getRequestHandler()->getRequest()->requestVar($requestVar);
+        if (!$sessionStateID) {
+            $sessionStateID = Controller::curr()->getRequest()->requestVar($requestVar);
+        }
+        if ($sessionStateID) {
+            return $sessionStateID;
+        }
+        $stateKey = $this->getStateKey($gridField);
+        if (isset(self::$state_ids[$stateKey])) {
+            $sessionStateID = self::$state_ids[$stateKey];
+        } elseif ($create) {
+            $sessionStateID = substr(md5(time()), 0, 8);
+            // we don't want session state id to be strictly numeric, since this is used as a session key,
+            // and session keys in php has to be usable as variable names
+            if (is_numeric($sessionStateID)) {
+                $sessionStateID .= 'a';
+            }
+            self::$state_ids[$stateKey] = $sessionStateID;
+        }
+        return $sessionStateID;
+    }
+
+    public function storeState(GridField $gridField, $value = null)
+    {
+        $sessionStateID = $this->getStateID($gridField, true);
+        $sessionState = Controller::curr()->getRequest()->getSession()->get($sessionStateID);
+        if (!$sessionState) {
+            $sessionState = [];
+        }
+        $stateKey = $this->getStateKey($gridField);
+        $sessionState[$stateKey] = $value ?? $gridField->getState(false)->Value();
+        Controller::curr()->getRequest()->getSession()->set($sessionStateID, $sessionState);
+    }
+
+    public function getStateRequestVar(): string
+    {
+        return 'gridSessionState';
+    }
+
+    /**
+     * @param GridField $gridField
+     * @return string
+     */
+    public function getStateKey(GridField $gridField): string
+    {
+        $record = $gridField->getForm()?->getRecord();
+        return $gridField->getName() . '-' . ($record ? $record->ID : 0);
+    }
+
+    /**
+     * @param GridField $gridField
+     * @param string $url
+     * @return string
+     */
+    public function addStateToURL(GridField $gridField, string $url): string
+    {
+        $sessionStateID = $this->getStateID($gridField);
+        if ($sessionStateID) {
+            return Controller::join_links($url, '?' . $this->getStateRequestVar() . '=' . $sessionStateID);
+        }
+        return $url;
+    }
+
+    /**
+     * @param GridField $gridField
+     * @param HTTPRequest $request
+     * @return string|null
+     */
+    public function getStateFromRequest(GridField $gridField, HTTPRequest $request): ?string
+    {
+        $gridSessionStateID = $request->requestVar($this->getStateRequestVar());
+        if ($gridSessionStateID) {
+            $sessionState = $request->getSession()->get($gridSessionStateID);
+            $stateKey = $this->getStateKey($gridField);
+            if ($sessionState && isset($sessionState[$stateKey])) {
+                return $sessionState[$stateKey];
+            }
+        }
+        return null;
+    }
+}

tests/php/Forms/GridField/SessionGridFieldStateManagerTest.php

@@ -0,0 +1,140 @@
+<?php
+
+namespace SilverStripe\Forms\Tests\GridField;
+
+use SilverStripe\Control\Controller;
+use SilverStripe\Control\HTTPRequest;
+use SilverStripe\Control\Session;
+use SilverStripe\Core\Injector\Injector;
+use SilverStripe\Dev\SapphireTest;
+use SilverStripe\Forms\FieldList;
+use SilverStripe\Forms\Form;
+use SilverStripe\Forms\GridField\GridField;
+use SilverStripe\Forms\GridField\GridFieldStateManagerInterface;
+use SilverStripe\Forms\GridField\SessionGridFieldStateManager;
+use SilverStripe\Forms\Tests\GridField\GridFieldPrintButtonTest\TestObject;
+
+class SessionGridFieldStateManagerTest extends SapphireTest
+{
+    protected function setUp(): void
+    {
+        parent::setUp();
+        // configure the injector to use the session grid field state manager
+        Injector::inst()->registerService(new SessionGridFieldStateManager(), GridFieldStateManagerInterface::class);
+    }
+
+    public function testStateKey()
+    {
+        $manager = new SessionGridFieldStateManager();
+        $controller = new Controller();
+        $form1 = new Form($controller, 'form1', new FieldList(), new FieldList());
+        $testObject = new TestObject();
+        $testObject->ID = 1;
+        $form2 = new Form($controller, 'form2', new FieldList(), new FieldList());
+        $form2->loadDataFrom($testObject);
+
+        $grid1 = new GridField('A');
+        $grid2 = new GridField('B');
+        $grid1->setForm($form1);
+        $grid2->setForm($form2);
+        $this->assertEquals('A-0', $manager->getStateKey($grid1));
+        $this->assertEquals('B-1', $manager->getStateKey($grid2));
+    }
+
+    public function testAddStateToURL()
+    {
+        $manager = new SessionGridFieldStateManager();
+        $grid = new GridField('TestGrid');
+        $grid->getState()->testValue = 'foo';
+        $stateRequestVar = $manager->getStateRequestVar();
+        $link = '/link-to/something';
+        $this->assertTrue(
+            preg_match(
+                "|^$link\?{$stateRequestVar}=[a-zA-Z0-9]+$|",
+                $manager->addStateToURL($grid, $link)
+            ) == 1
+        );
+
+        $link = '/link-to/something-else?someParam=somevalue';
+        $this->assertTrue(
+            preg_match(
+                "|^/link-to/something-else\?someParam=somevalue&{$stateRequestVar}=[a-zA-Z0-9]+$|",
+                $manager->addStateToURL($grid, $link)
+            ) == 1
+        );
+    }
+
+    public function testGetStateFromRequest()
+    {
+        $manager = new SessionGridFieldStateManager();
+
+        $session = new Session([]);
+        $request = new HTTPRequest(
+            'GET',
+            '/link-to/something',
+            [
+                $manager->getStateRequestVar() => 'testGetStateFromRequest'
+            ]
+        );
+        $request->setSession($session);
+
+        $controller = new Controller();
+        $controller->setRequest($request);
+        $controller->pushCurrent();
+        $form = new Form($controller, 'form1', new FieldList(), new FieldList());
+        $grid = new GridField('TestGrid');
+        $grid->setForm($form);
+
+        $grid->getState()->testValue = 'foo';
+        $state = $grid->getState(false)->Value() ?? '{}';
+        $result = $manager->getStateFromRequest($grid, $request);
+
+        $this->assertEquals($state, $result);
+        $controller->popCurrent();
+    }
+
+    public function testDefaultStateLeavesURLUnchanged()
+    {
+        $manager = new SessionGridFieldStateManager();
+        $grid = new GridField('DefaultStateGrid');
+        $grid->getState(false)->getData()->testValue->initDefaults(['foo' => 'bar']);
+        $link = '/link-to/something';
+
+        $this->assertEquals('{}', $grid->getState(false)->Value());
+
+        $this->assertEquals(
+            '/link-to/something',
+            $manager->addStateToURL($grid, $link)
+        );
+    }
+
+    public function testStoreState()
+    {
+        $manager = new SessionGridFieldStateManager();
+
+        $session = new Session([]);
+        $request = new HTTPRequest(
+            'GET',
+            '/link-to/something',
+            [
+                $manager->getStateRequestVar() => 'testStoreState'
+            ]
+        );
+        $request->setSession($session);
+
+        $controller = new Controller();
+        $controller->setRequest($request);
+        $controller->pushCurrent();
+        $form = new Form($controller, 'form1', new FieldList(), new FieldList());
+        $grid = new GridField('TestGrid');
+        $grid->setForm($form);
+
+        $grid->getState()->testValue = 'foo';
+        $state = $grid->getState(false)->Value() ?? '{}';
+
+        $manager->storeState($grid);
+        $this->assertEquals($state, $session->get('testStoreState')['TestGrid-0']);
+
+        $controller->popCurrent();
+    }
+}