IMPR: AJAX processing

_config/base-extensions.yml

@@ -45,6 +45,8 @@ SilverStripe\Core\Injector\Injector:
     class: A2nt\CMSNiceties\Forms\GridField\GridFieldConfig_RecordEditor
   SilverStripe\Forms\GridField\GridFieldConfig_RelationEditor:
     class: A2nt\CMSNiceties\Forms\GridField\GridFieldConfig_RelationEditor
+  SilverStripe\Forms\FormRequestHandler:
+    class: A2nt\CMSNiceties\Ajax\AjaxFormRequestHandler
 
 SilverStripe\UserForms\Form\UserForm:
   extensions:

src/Ajax/AjaxFormRequestHandler.php

@@ -0,0 +1,44 @@
+<?php
+
+namespace A2nt\CMSNiceties\Ajax;
+
+use A2nt\CMSNiceties\Ajax\Ex\AjaxControllerEx;
+use SilverStripe\Forms\FormRequestHandler;
+use SilverStripe\ORM\ValidationResult;
+
+class AjaxFormRequestHandler extends FormRequestHandler
+{
+    private static $allowed_actions = [
+        'httpSubmission',
+    ];
+
+    /**
+     * Handle a form submission.  GET and POST requests behave identically.
+     * Populates the form with {@link loadDataFrom()}, calls {@link validate()},
+     * and only triggers the requested form action/method
+     * if the form is valid.
+     *
+     * @param HTTPRequest $request
+     * @return HTTPResponse
+     * @throws HTTPResponse_Exception
+     */
+    public function httpSubmission($request)
+    {
+        $resp = parent::httpSubmission($request);
+
+        if (!AjaxControllerEx::isFormRequest()) {
+            return $resp;
+        }
+
+        $validation = $this->form->validationResult();
+        if (!$validation->isValid()) {
+            $messages = $validation->getMessages();
+            return json_encode([
+                'status' => ValidationResult::TYPE_ERROR,
+                'msgs' => $messages,
+            ]);
+        }
+
+        return $resp;
+    }
+}

src/Ajax/Ex/AjaxControllerEx.php

@@ -4,7 +4,6 @@ namespace A2nt\CMSNiceties\Ajax\Ex;
 
 use SilverStripe\Control\Controller;
 use SilverStripe\Control\Director;
-use SilverStripe\Control\HTTPRequest;
 use SilverStripe\Core\Extension;
 use SilverStripe\Core\Injector\Injector;
 use SilverStripe\Forms\Form;