bug #691 [Platform][OpenAI] Improve error reporting for Bad Request (oesteve)

This PR was squashed before being merged into the main branch.

Discussion
----------

[Platform][OpenAI] Improve error reporting for Bad Request

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| Docs?         | no
| Issues        | Fix #528
| License       | MIT

I've noted an interesting initiative at symfony/ai#574 to handle non-valid response codes in a more structured and scalable way. This approach makes sense to me, but it may require further reflection. With this PR, I aim to contribute a humble and specific use case for OpenAI, along with an Exception class that could be reused for the other bridges.

Commits
-------

c39bbbf4 [Platform][OpenAI] Improve error reporting for Bad Request

Author: chr-hertel

src/Bridge/OpenAi/Gpt/ResultConverter.php

@@ -13,6 +13,7 @@
 
 use Symfony\AI\Platform\Bridge\OpenAi\Gpt;
 use Symfony\AI\Platform\Exception\AuthenticationException;
+use Symfony\AI\Platform\Exception\BadRequestException;
 use Symfony\AI\Platform\Exception\ContentFilterException;
 use Symfony\AI\Platform\Exception\RateLimitExceededException;
 use Symfony\AI\Platform\Exception\RuntimeException;
@@ -50,6 +51,11 @@ public function convert(RawResultInterface|RawHttpResult $result, array $options
             throw new AuthenticationException($errorMessage);
         }
 
+        if (400 === $response->getStatusCode()) {
+            $errorMessage = json_decode($response->getContent(false), true)['error']['message'] ?? 'Bad Request';
+            throw new BadRequestException($errorMessage);
+        }
+
         if (429 === $response->getStatusCode()) {
             $headers = $response->getHeaders(false);
             $resetTime = null;

src/Exception/BadRequestException.php

@@ -0,0 +1,19 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\AI\Platform\Exception;
+
+/**
+ * @author Oscar Esteve <[email protected]>
+ */
+class BadRequestException extends RuntimeException
+{
+}

tests/Bridge/OpenAi/Gpt/ResultConverterTest.php

@@ -14,6 +14,7 @@
 use PHPUnit\Framework\TestCase;
 use Symfony\AI\Platform\Bridge\OpenAi\Gpt\ResultConverter;
 use Symfony\AI\Platform\Exception\AuthenticationException;
+use Symfony\AI\Platform\Exception\BadRequestException;
 use Symfony\AI\Platform\Exception\ContentFilterException;
 use Symfony\AI\Platform\Exception\RuntimeException;
 use Symfony\AI\Platform\Result\ChoiceResult;
@@ -196,4 +197,33 @@ public function testThrowsExceptionForUnsupportedFinishReason()
 
         $converter->convert(new RawHttpResult($httpResponse));
     }
+
+    public function testThrowsBadRequestExceptionOnBadRequestResponse()
+    {
+        $converter = new ResultConverter();
+        $httpResponse = self::createMock(ResponseInterface::class);
+        $httpResponse->method('getStatusCode')->willReturn(400);
+        $httpResponse->method('getContent')->willReturn(json_encode([
+            'error' => [
+                'message' => 'Bad Request: invalid parameters',
+            ],
+        ]));
+
+        $this->expectException(BadRequestException::class);
+        $this->expectExceptionMessage('Bad Request: invalid parameters');
+
+        $converter->convert(new RawHttpResult($httpResponse));
+    }
+
+    public function testThrowsBadRequestExceptionOnBadRequestResponseWithNoResponseBody()
+    {
+        $converter = new ResultConverter();
+        $httpResponse = self::createMock(ResponseInterface::class);
+        $httpResponse->method('getStatusCode')->willReturn(400);
+
+        $this->expectException(BadRequestException::class);
+        $this->expectExceptionMessage('Bad Request');
+
+        $converter->convert(new RawHttpResult($httpResponse));
+    }
 }