Throw a proper exception when transformation fails

Form/DataTransformer/HCaptchaValueFetcher.php

@@ -3,6 +3,7 @@
 namespace MeteoConcept\HCaptchaBundle\Form\DataTransformer;
 
 use Symfony\Component\Form\DataTransformerInterface;
+use Symfony\Component\Form\Exception\TransformationFailedException;
 use Symfony\Component\HttpFoundation\RequestStack;
 
 use MeteoConcept\HCaptchaBundle\Form\HCaptchaResponse;
@@ -71,20 +72,25 @@ public function transform($value)
      */
     public function reverseTransform($value)
     {
-        /*
-         * We need to get the data directly from the request since hCaptcha uses
-         * the POST variable h-captcha-response instead of a nicely named
-         * variable that would let the Symfony Form component find it on its own.
-         */
-        $masterRequest = $this->requestStack->getMainRequest();
-        $response      = $masterRequest->get("h-captcha-response");
+        try {
+            /*
+             * We need to get the data directly from the request since hCaptcha uses
+             * the POST variable h-captcha-response instead of a nicely named
+             * variable that would let the Symfony Form component find it on its own.
+             */
+            $masterRequest = $this->requestStack->getMainRequest();
+            $response      = $masterRequest->get("h-captcha-response");
 
-        // Can happen if the Captcha JS has failed to load for instance
-        if (null === $response)
-            return null;
+            // Can happen if the Captcha JS has failed to load for instance
+            if (null === $response)
+                return null;
 
-        $remoteIp = $masterRequest->getClientIp();
+            $remoteIp = $masterRequest->getClientIp();
 
-        return new HCaptchaResponse($response, $remoteIp, $this->siteKey);
+            return new HCaptchaResponse($response, $remoteIp, $this->siteKey);
+        } catch (\TypeError $error) {
+            // can happen if $response is not a string but an array for instance
+            throw new TransformationFailedException("Unable to extract the HCaptcha value from the query");
+        }
     }
 }

Form/HCaptchaType.php

@@ -98,6 +98,7 @@ public function configureOptions(OptionsResolver $resolver): void
                 new NotBlank(["message" => "The CAPTCHA is required."]),
                 new IsValidCaptcha(),
             ],
+            'invalid_message' => "Invalid CAPTCHA",
         ]);
 
         /*

Tests/Units/Form/DataTransformer/HCaptchaValueFetcherTest.php

@@ -3,6 +3,7 @@
 namespace MeteoConcept\HCaptchaBundle\Tests\Units\Form\DataTransformer;
 
 use PHPUnit\Framework\TestCase;
+use Symfony\Component\Form\Exception\TransformationFailedException;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\RequestStack;
 
@@ -19,6 +20,10 @@ class HCaptchaValueFetcherTest extends TestCase
 
     private $noCaptchaRequest;
 
+    private $multipleCaptchaRequestStack;
+
+    private $multipleCaptchaRequest;
+
     public function setUp(): void
     {
         $this->requestStack = $this->createMock(RequestStack::class);
@@ -48,6 +53,20 @@ public function setUp(): void
         $this->noCaptchaRequestStack->expects($this->any())
                            ->method('getMainRequest')
                            ->willReturn($this->noCaptchaRequest);
+
+        $this->multipleCaptchaRequestStack = $this->createMock(RequestStack::class);
+        $this->multipleCaptchaRequest = Request::create(
+            '/some_route',
+            'POST',
+            [ 'h-captcha-response' => ['some_response1', 'some_response2'] ], // request parameters
+            [], // cookies
+            [], // files
+            [ 'REMOTE_ADDR' => '10.0.1.1' ], // server
+            ''
+        );
+        $this->multipleCaptchaRequestStack->expects($this->any())
+                           ->method('getMainRequest')
+                           ->willReturn($this->multipleCaptchaRequest);
     }
 
     public function test_The_value_fetcher_builds_the_correct_form_value_from_the_request()
@@ -75,4 +94,13 @@ public function test_The_value_fetcher_does_not_do_transformation_from_model_to_
         $value = $valueFetcher->transform(null);
         $this->assertEquals(null, $value);
     }
+
+    public function test_The_value_fetcher_throws_a_TransformationFailedException_if_the_request_contains_an_array_of_captchas()
+    {
+        $valueFetcher = new HCaptchaValueFetcher($this->multipleCaptchaRequestStack);
+        $valueFetcher->setSiteKey('some_site_key');
+
+        $this->expectException(TransformationFailedException::class);
+        $value = $valueFetcher->reverseTransform(null);
+    }
 }