refactor(request): propagate validation failures as exceptions

src/Libs/Request.php

@@ -2,6 +2,8 @@
 
 namespace Libs;
 
+use Exception;
+
 /**
  * Request - DuckBrain
  *
@@ -59,17 +61,20 @@ class Request extends Neuron
         }
 
         // Run configured validations
-        if (!$this->validate()) {
+        $this->validate();
-            exit();
-        }
     }
 
     /**
      * Starts the configured validation.
      *
-     * @return bool
+     * On failure the single error message is built with Validator::message()
+     * and handed to onInvalid(), which throws by default: failures travel up
+     * as exceptions instead of answering HTTP here.
+     *
+     * @return void
+     * @throws Exception When a configured rule fails.
      */
-    public function validate(): bool
+    public function validate(): void
     {
         $actual = match ($_SERVER['REQUEST_METHOD']) {
             'POST', 'PUT', 'PATCH', 'DELETE' => $this->{strtolower($_SERVER['REQUEST_METHOD'])},
@@ -88,7 +93,7 @@ class Request extends Neuron
             Validator::validateList(static::getRules(), $this->get) &&
             Validator::validateList(static::rules(), $body)
         ) {
-            return true;
+            return;
         }
 
         $error = Validator::message(
@@ -98,7 +103,6 @@ class Request extends Neuron
         );
 
         static::onInvalid($error);
-        return false;
     }
 
     /**
@@ -157,27 +161,20 @@ class Request extends Neuron
     /**
      * Function to execute when an invalid value has been detected.
      *
-     * Always answers with a single error and HTTP 422. The representation is
+     * The default implementation always throws a generic \Exception carrying
-     * negotiated from the request's Accept header: JSON when the client asks
+     * the single error message and HTTP 422 as its code; the framework's
-     * for application/json, plain text otherwise.
+     * exception boundary (Router::apply) renders the response. Override it to
+     * throw a more specific exception type instead. The never return type is
+     * the contract: an override that returned would let the request continue
+     * with invalid data, so PHP rejects such an override at compile time.
      *
      * @param string $error
      *
-     * @return void
+     * @return never
+     * @throws Exception
      */
-    public function onInvalid(string $error): void
+    public function onInvalid(string $error): never
     {
-        http_response_code(422);
+        throw new Exception($error, 422);
-
-        $accept = $_SERVER['HTTP_ACCEPT'] ?? '';
-
-        if (str_contains($accept, 'application/json')) {
-            header('Content-Type: application/json');
-            print(json_encode(['error' => $error]));
-
-            return;
-        }
-
-        print($error);
     }
 }