add first lines of docs

symfony · y4roc · Jan 21, 2023 · Jan 21, 2023 · 0f7fb95eb6e0fedb23a32cc622b652effb6d69df
commit 0f7fb95eb6e0fedb23a32cc622b652effb6d69df
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+.. index::
+    single: Validation; Validating request inputs
+
+How to Validate Request Inputs
+==============================
+
+Most of the time, you first validate a request to see if the data
+sent is valid. To end the call early with a "BadRequestResponse"
+in case of incorrect data.
+
+With the attribute RequestValidator in front of your action method
+you can fill a previously defined request class with the sent data
+and validate it automatically. If the data is incorrect, an exception
+is thrown before the request arrives in the controller method.
+
+RequestClass
+------------
+
+A very simple example of a GetUserRequest would look like this:
+
+    // src/Request/GetUserRequest.php
+    namespace App\Request;
+
+    use Symfony\Component\Validator\Constraints as Assert;
+
+    class GetUserRequest
+    {
+        #[Assert\Type(type: 'digit')]
+        #[Assert\NotBlank]
+        public $id;
+
+        public function getId(): int
+        {
+            return intval($this->id);
+        }
+    }
+
+ControllerClass
+---------------
+
+And the controller would look like this in the above example:
+
+    // src/Controller/GetUserAction.php
+    namespace App\Controller;
+
+    use App\Request\GetUserRequest;
+    use Symfony\Component\Routing\Annotation\Route;
+    use Symfony\Component\Validator\Attribute\RequestValidator;
+
+    class GetUserAction
+    {
+        #[Route(path: '/user', methods: ['GET']]
+        #RequestValidator[class: GetUserRequest::class]
+        public __invoke(GetUserRequest $request)
+        {
+            $userId = $request->getId();
+            ...
+        }
+    }