Create validation_group_service_resolver.rst

Author: afurculita

form/validation_group_service_resolver.rst

@@ -0,0 +1,72 @@
+How to Dynamically Configure Form Validation Groups
+==============================================
+
+Sometimes you need advanced logic to determine the validation groups. If they
+can't be determined by a simple callback, you can use a service. Create a
+service that implements ``__invoke()`` which accepts a ``FormInterface`` as a
+parameter.
+
+.. code-block:: php
+
+    // src/AppBundle/Validation/ValidationGroupResolver.php
+    namespace AppBundle\Validation;
+
+    use Symfony\Component\Form\FormInterface;
+
+    class ValidationGroupResolver
+    {
+        private $service1;
+
+        private $service2;
+
+        public function __construct($service1, $service2)
+        {
+            $this->service1 = $service1;
+            $this->service2 = $service2;
+        }
+
+        /**
+         * @param FormInterface $form
+         * @return array
+         */
+        public function __invoke(FormInterface $form)
+        {
+            $groups = array();
+
+            // ... determine which groups to apply and return an array
+
+            return $groups;
+        }
+    }
+
+Then in your form, inject the resolver and set it as the ``validation_groups``.
+
+.. code-block:: php
+
+    // src/AppBundle/Form/MyClassType.php;
+    namespace AppBundle\Form;
+
+    use AppBundle\Validator\ValidationGroupResolver;
+    use Symfony\Component\Form\AbstractType
+    use Symfony\Component\OptionsResolver\OptionsResolver;
+
+    class MyClassType extends AbstractType
+    {
+        private $groupResolver;
+
+        public function __construct(ValidationGroupResolver $groupResolver)
+        {
+            $this->groupResolver = $groupResolver;
+        }
+
+        // ...
+        public function configureOptions(OptionsResolver $resolver)
+        {
+            $resolver->setDefaults(array(
+                'validation_groups' => $this->groupResolver,
+            ));
+        }
+    }
+
+This will result in the form validator invoking your group resolver to set the
+validation groups returned when validating.