Refactored grid field nested form link to be a button with aria-attributes,

for better accessibility.

javascript/GridFieldExtensions.js

@@ -517,7 +517,7 @@
 		/**
 		 * GridFieldNestedForm
 		 */
-		$('.grid-field .col-listChildrenLink a').entwine({
+		$('.grid-field .col-listChildrenLink button').entwine({
 			onclick: function(e) {
 				let gridField = $(this).closest('.grid-field');
 				let currState = gridField.getState();
@@ -552,7 +552,7 @@
 						}
 						$.ajax({
 							type: 'POST',
-							url: $(this).attr('href'),
+							url: $(this).attr('data-url'),
 							data: data,
 							headers: {
 								'X-Pjax': pjaxTarget
@@ -572,6 +572,7 @@
 					}
 					$(this).removeClass('font-icon-right-dir');
 					$(this).addClass('font-icon-down-dir');
+					$(this).attr('aria-expanded', 'true');
 				}
 				else {
 					$.ajax({
@@ -580,6 +581,7 @@
 					$(this).closest('tr').next('.nested-gridfield').hide();
 					$(this).removeClass('font-icon-down-dir');
 					$(this).addClass('font-icon-right-dir');
+					$(this).attr('aria-expanded', 'false');
 				}
 				e.preventDefault();
 				e.stopPropagation();

src/GridFieldNestedForm.php

@@ -6,8 +6,10 @@ use Exception;
 use SilverStripe\Admin\ModelAdmin;
 use SilverStripe\Control\Controller;
 use SilverStripe\Control\Director;
+use SilverStripe\Control\HTTPRequest;
 use SilverStripe\Control\HTTPResponse;
 use SilverStripe\Control\HTTPResponse_Exception;
+use SilverStripe\Control\RequestHandler;
 use SilverStripe\Core\Config\Configurable;
 use SilverStripe\Forms\GridField\AbstractGridFieldComponent;
 use SilverStripe\Forms\GridField\GridField;
@@ -16,11 +18,11 @@ use SilverStripe\Forms\GridField\GridField_DataManipulator;
 use SilverStripe\Forms\GridField\GridField_HTMLProvider;
 use SilverStripe\Forms\GridField\GridField_SaveHandler;
 use SilverStripe\Forms\GridField\GridField_URLHandler;
-use SilverStripe\Forms\GridField\GridFieldDetailForm_ItemRequest;
 use SilverStripe\Forms\GridField\GridFieldStateAware;
 use SilverStripe\ORM\DataList;
 use SilverStripe\ORM\DataObject;
 use SilverStripe\ORM\DataObjectInterface;
+use SilverStripe\ORM\Filterable;
 use SilverStripe\ORM\Hierarchy\Hierarchy;
 use SilverStripe\ORM\SS_List;
 use SilverStripe\Versioned\Versioned;
@@ -39,26 +41,61 @@ class GridFieldNestedForm extends AbstractGridFieldComponent implements
 {
     use Configurable, GridFieldStateAware;
     
+    /**
+     * The key used in the post data to identify nested form data
+     */
     const POST_KEY = 'GridFieldNestedForm';
 
     private static $allowed_actions = [
         'handleNestedItem'
     ];
 
-    private static $max_nesting_level = 10;
+    /**
+     * The default max nesting level. Nesting further than this will throw an exception.
+     *
+     * @var boolean
+     */
+    private static $default_max_nesting_level = 10;
     
     /**
      * @var string
      */
-    protected $name;
+    private $name;
-    protected $expandNested = false;
+
-    protected $forceCloseNested = false;
+    /**
-    protected $gridField = null;
+     * @var bool
-    protected $record = null;
+     */
-    protected $relationName = 'Children';
+    private $expandNested = false;
-    protected $inlineEditable = false;
+
-    protected $canExpandCheck = null;
+    /**
-    protected $maxNestingLevel = null;
+     * @var bool
+     */
+    private $forceCloseNested = false;
+
+    /**
+     * @var GridField
+     */
+    private $gridField = null;
+
+    /**
+     * @var string
+     */
+    private $relationName = 'Children';
+
+    /**
+     * @var bool
+     */
+    private $inlineEditable = false;
+
+    /**
+     * @var callable|string
+     */
+    private $canExpandCheck = null;
+
+    /**
+     * @var int
+     */
+    private $maxNestingLevel = null;
     
     public function __construct($name = 'NestedForm')
     {
@@ -67,27 +104,24 @@ class GridFieldNestedForm extends AbstractGridFieldComponent implements
     
     /**
      * Get the grid field that this component is attached to
-     * @return GridField
      */
-    public function getGridField()
+    public function getGridField(): GridField
     {
         return $this->gridField;
     }
 
     /**
      * Get the relation name to use for the nested grid fields
-     * @return string
      */
-    public function getRelationName()
+    public function getRelationName(): string
     {
         return $this->relationName;
     }
     
     /**
      * Set the relation name to use for the nested grid fields
-     * @param string $relationName
      */
-    public function setRelationName($relationName)
+    public function setRelationName(string $relationName)
     {
         $this->relationName = $relationName;
         return $this;
@@ -95,18 +129,16 @@ class GridFieldNestedForm extends AbstractGridFieldComponent implements
 
     /**
      * Get whether the nested grid fields should be inline editable
-     * @return boolean
      */
-    public function getInlineEditable()
+    public function getInlineEditable(): bool
     {
         return $this->inlineEditable;
     }
 
     /**
      * Set whether the nested grid fields should be inline editable
-     * @param boolean $editable
      */
-    public function setInlineEditable($editable)
+    public function setInlineEditable(bool $editable)
     {
         $this->inlineEditable = $editable;
         return $this;
@@ -114,9 +146,8 @@ class GridFieldNestedForm extends AbstractGridFieldComponent implements
     
     /**
      * Set whether the nested grid fields should be expanded by default
-     * @param boolean $expandNested
      */
-    public function setExpandNested($expandNested)
+    public function setExpandNested(bool $expandNested)
     {
         $this->expandNested = $expandNested;
         return $this;
@@ -124,49 +155,54 @@ class GridFieldNestedForm extends AbstractGridFieldComponent implements
 
     /**
      * Set whether the nested grid fields should be forced closed on load
-     * @param boolean $forceClosed
      */
-    public function setForceClosedNested($forceClosed)
+    public function setForceClosedNested(bool $forceClosed)
     {
         $this->forceCloseNested = $forceClosed;
         return $this;
     }
 
     /**
-     * Set a callback to check which items in this grid that should show the expand link
+     * Set a callback function to check which items in this grid that should show the expand link
      * for nested gridfields. The callback should return a boolean value.
-     * @param callable $checkFunction
+     * You can either pass a callable or a method name as a string.
      */
-    public function setCanExpandCheck($checkFunction)
+    public function setCanExpandCheck(callable|string $callback)
     {
-        $this->canExpandCheck = $checkFunction;
+        $this->canExpandCheck = $callback;
         return $this;
     }
 
     /**
      * Set the maximum nesting level allowed for nested grid fields
-     * @param int $level
      */
-    public function setMaxNestingLevel($level)
+    public function setMaxNestingLevel(int $level)
     {
         $this->maxNestingLevel = $level;
         return $this;
     }
 
-    public function getMaxNestingLevel()
+    /**
+     * Get the max nesting level allowed for this grid field.
+     */
+    public function getMaxNestingLevel(): int
     {
-        return $this->maxNestingLevel ?: $this->config()->max_nesting_level;
+        return $this->maxNestingLevel ?: static::config()->get('default_max_nesting_level');
     }
 
-    protected function getNestingLevel($gridField)
+    /**
+     * Check if we are currently at the max nesting level allowed.
+     */
+    protected function atMaxNestingLevel(GridField $gridField): bool
     {
         $level = 0;
-        $c = $gridField->getForm()->getController();
+        $controller = $gridField->getForm()->getController();
-        while ($c && $c instanceof GridFieldDetailForm_ItemRequest) {
+        $maxLevel = $this->getMaxNestingLevel();
-            $c = $c->getController();
+        while ($level < $maxLevel && $controller && $controller instanceof GridFieldNestedFormItemRequest) {
+            $controller = $controller->getController();
             $level++;
         }
-        return $level;
+        return $level >= $maxLevel;
     }
 
     public function getColumnMetadata($gridField, $columnName)
@@ -193,14 +229,12 @@ class GridFieldNestedForm extends AbstractGridFieldComponent implements
 
     public function getColumnContent($gridField, $record, $columnName)
     {
-        $nestingLevel = $this->getNestingLevel($gridField);
+        if ($this->atMaxNestingLevel($gridField)) {
-        if ($nestingLevel >= $this->getMaxNestingLevel()) {
             return '';
         }
         $gridField->addExtraClass('has-nested');
         if ($record->ID && $record->exists()) {
             $this->gridField = $gridField;
-            $this->record = $record;
             $relationName = $this->getRelationName();
             if (!$record->hasMethod($relationName)) {
                 return '';
@@ -212,7 +246,7 @@ class GridFieldNestedForm extends AbstractGridFieldComponent implements
                     return '';
                 } elseif (is_string($this->canExpandCheck)
                     && $record->hasMethod($this->canExpandCheck)
-                    && !$this->record->{$this->canExpandCheck}($record)
+                    && !$record->{$this->canExpandCheck}($record)
                 ) {
                     return '';
                 }
@@ -251,15 +285,30 @@ class GridFieldNestedForm extends AbstractGridFieldComponent implements
     }
 
     /**
-     * @param GridField $field
+     * @param GridField $gridField
+     * @return array
      */
-    public function getHTMLFragments($field)
+    public function getHTMLFragments($gridField)
     {
-        if (DataObject::has_extension($field->getModelClass(), Hierarchy::class)) {
+        /**
-            $field->setAttribute('data-url-movetoparent', $field->Link('movetoparent'));
+         * If we have a DataObject with the hierarchy extension, we want to allow moving items to a new parent.
+         * This is enabled by setting the data-url-movetoparent attribute on the grid field, so that the client
+         * javascript can handle the move.
+         * Implemented in getHTMLFragments since this attribute needs to be added before any rendering happens.
+         */
+        if (is_a($gridField->getModelClass(), DataObject::class, true)
+            && DataObject::has_extension($gridField->getModelClass(), Hierarchy::class)
+        ) {
+            $gridField->setAttribute('data-url-movetoparent', $gridField->Link('movetoparent'));
         }
+        return [];
     }
 
+    /**
+     * Handle moving a record to a new parent
+     *
+     * @return string
+     */
     public function handleMoveToParent(GridField $gridField, $request)
     {
         $move = $request->postVar('move');
@@ -326,22 +375,30 @@ class GridFieldNestedForm extends AbstractGridFieldComponent implements
         return $gridField->FieldHolder();
     }
     
+    /**
+     * Handle the request to show a nested item
+     *
+     * @param GridField $gridField
+     * @param HTTPRequest|null $request
+     * @param ViewableData|null $record
+     * @return HTTPResponse|RequestHandler
+     */
     public function handleNestedItem(GridField $gridField, $request = null, $record = null)
     {
-        $nestingLevel = $this->getNestingLevel($gridField);
+        if ($this->atMaxNestingLevel($gridField)) {
-        if ($nestingLevel >= $this->getMaxNestingLevel()) {
             throw new Exception('Max nesting level reached');
         }
-        if (!$record && $request) {
+        $list = $gridField->getList();
+        if (!$record && $request && $list instanceof Filterable) {
             $recordID = $request->param('RecordID');
-            $record = $gridField->getList()->byID($recordID);
+            $record = $list->byID($recordID);
         }
         if (!$record) {
             return '';
         }
         $relationName = $this->getRelationName();
         if (!$record->hasMethod($relationName)) {
-            return '';
+            throw new Exception('Invalid relation name');
         }
         $manager = $this->getStateManager();
         $stateRequest = $request ?: $gridField->getForm()->getRequestHandler()->getRequest();
@@ -349,7 +406,6 @@ class GridFieldNestedForm extends AbstractGridFieldComponent implements
             $gridField->getState(false)->setValue($gridStateStr);
         }
         $this->gridField = $gridField;
-        $this->record = $record;
         $itemRequest = GridFieldNestedFormItemRequest::create(
             $gridField,
             $this,
@@ -373,11 +429,19 @@ class GridFieldNestedForm extends AbstractGridFieldComponent implements
         }
     }
 
+    /**
+     * Handle the request to toggle a nested item in the gridfield state
+     *
+     * @param GridField $gridField
+     * @param HTTPRequest|null $request
+     * @param ViewableData|null $record
+     */
     public function toggleNestedItem(GridField $gridField, $request = null, $record = null)
     {
-        if (!$record) {
+        $list = $gridField->getList();
+        if (!$record && $request && $list instanceof Filterable) {
             $recordID = $request->param('RecordID');
-            $record = $gridField->getList()->byID($recordID);
+            $record = $list->byID($recordID);
         }
         $manager = $this->getStateManager();
         if ($gridStateStr = $manager->getStateFromRequest($gridField, $request)) {
@@ -389,14 +453,20 @@ class GridFieldNestedForm extends AbstractGridFieldComponent implements
         $state->$stateRelation = (int)$request->getVar('toggle');
     }
     
-    public function Link($action = null)
+    /**
+     * Get the link for the nested grid field
+     */
+    public function Link($action = null): string
     {
         $link = Director::absoluteURL(Controller::join_links($this->gridField->Link('nested'), $action));
         $manager = $this->getStateManager();
         return $manager->addStateToURL($this->gridField, $link);
     }
 
-    public function ToggleLink($action = null)
+    /**
+     * Get the link for the toggle action
+     */
+    public function ToggleLink($action = null): string
     {
         $link = Director::absoluteURL(Controller::join_links($this->gridField->Link('toggle'), $action, '?toggle='));
         $manager = $this->getStateManager();
@@ -417,11 +487,13 @@ class GridFieldNestedForm extends AbstractGridFieldComponent implements
             $gridField->getState(false)->setValue($gridStateStr);
         }
         foreach ($request->postVars() as $key => $val) {
-            if (preg_match("/{$gridField->getName()}-{$postKey}-(\d+)/", $key, $matches)) {
+            $list = $gridField->getList();
+            if ($list instanceof Filterable && preg_match("/{$gridField->getName()}-{$postKey}-(\d+)/", $key, $matches)) {
                 $recordID = $matches[1];
                 $nestedData = $val;
-                $record = $gridField->getList()->byID($recordID);
+                $record = $list->byID($recordID);
                 if ($record) {
+                    /** @var GridField */
                     $nestedGridField = $this->handleNestedItem($gridField, null, $record);
                     $nestedGridField->setValue($nestedData);
                     $nestedGridField->saveInto($record);
@@ -433,8 +505,10 @@ class GridFieldNestedForm extends AbstractGridFieldComponent implements
     public function getManipulatedData(GridField $gridField, SS_List $dataList)
     {
         if ($this->relationName == 'Children'
+            && is_a($gridField->getModelClass(), DataObject::class, true)
             && DataObject::has_extension($gridField->getModelClass(), Hierarchy::class)
             && $gridField->getForm()->getController() instanceof ModelAdmin
+            && $dataList instanceof Filterable
         ) {
             $dataList = $dataList->filter('ParentID', 0);
         }

src/GridFieldNestedFormItemRequest.php

@@ -24,9 +24,11 @@ use Symbiote\GridFieldExtensions\GridFieldAddNewInlineButton;
 use Symbiote\GridFieldExtensions\GridFieldEditableColumns;
 use Symbiote\GridFieldExtensions\GridFieldOrderableRows;
 
+/**
+ * Request handler class for nested grid field forms.
+ */
 class GridFieldNestedFormItemRequest extends GridFieldDetailForm_ItemRequest
 {
-    
     public function Link($action = null)
     {
         return Controller::join_links($this->component->Link($this->record->ID), $action);
@@ -72,7 +74,10 @@ class GridFieldNestedFormItemRequest extends GridFieldDetailForm_ItemRequest
             }
 
             if ($this->record->hasExtension(Hierarchy::class)) {
-                $config->addComponent(new GridFieldNestedForm(), GridFieldOrderableRows::class);
+                $config->addComponent($nestedForm = new GridFieldNestedForm(), GridFieldOrderableRows::class);
+                // use max nesting level from parent component
+                $nestedForm->setMaxNestingLevel($this->component->getMaxNestingLevel());
+
                 /** @var GridFieldOrderableRows */
                 $orderableRows = $config->getComponentByType(GridFieldOrderableRows::class);
                 if ($orderableRows) {
@@ -117,8 +122,6 @@ class GridFieldNestedFormItemRequest extends GridFieldDetailForm_ItemRequest
         $gridField->setAttribute('data-class', str_replace('\\', '-', $relationClass));
         $gridField->addExtraClass('nested');
         $form = new Form($this, 'ItemEditForm', $fields, new FieldList());
-        $form->setStrictFormMethodCheck(false);
-        $form->disableSecurityToken();
 
         $className = str_replace('\\', '-', get_class($this->record));
         $state = $this->gridField->getState()->GridFieldNestedForm;

templates/Symbiote/GridFieldExtensions/GridFieldNestedForm.ss

@@ -1,4 +1,10 @@
-<a class="btn btn-secondary btn--no-text btn--icon-large <% if $Toggle == 'open' %>font-icon-down-dir<% else %>font-icon-right-dir<% end_if %> cms-panel-link list-children-link" data-pjax-target="$PjaxFragment" href="$Link" data-toggle="$ToggleLink"></a>
+<button
+	class="btn btn-secondary btn--no-text btn--icon-large <% if $Toggle == 'open' %>font-icon-down-dir<% else %>font-icon-right-dir<% end_if %> cms-panel-link list-children-link"
+	aria-expanded="<% if $Toggle == 'open' %>true<% else %>false<% end_if %>"
+	data-pjax-target="$PjaxFragment"
+	data-url="$Link"
+	data-toggle="$ToggleLink"
+></button>
 <% if $Toggle == 'open' %>
 	$NestedField
 <% else %>