GraphQl query showing 500 when post when blank query

Question

In Magento 2 when post graphql with empty query it results into 500 error.

It should not give 500 error and proper response.

https://www.test.com/graphql

{
"errors": [
 {
 "message": "Syntax Error: Unexpected <EOF>",
 "locations": [
 {
 "line": 1,
 "column": 1
 }
 ],
 "extensions": {
 "file": "/var/www/html/vendor/webonyx/graphql-php/src/Language/Parser.php",
 "line": 437
 }
 }
]

}

Answer 1

If you want to prevent empty GraphQL requests in Magento 2 and return a proper error response when the request body is empty or invalid JSON, you can create a plugin for the GraphQL controller.

Step 1: Add a plugin in di.xml

<type name="Magento\GraphQl\Controller\GraphQl">
<plugin name="prevent_empty_graphql"
 type="Vendor\Module\Plugin\PreventEmptyGraphQl"
 sortOrder="10"/>

Step 2: Create the plugin class PreventEmptyGraphQl.php

<?php

namespace Vendor\Module\Plugin;

use Magento\Framework\App\RequestInterface; use Magento\Framework\App\ResponseInterface; use Magento\Framework\Controller\Result\JsonFactory; use Magento\Framework\App\Response\Http as HttpResponse; use Magento\Framework\App\ObjectManager; use Magento\Framework\Serialize\SerializerInterface;

class PreventEmptyGraphQl { protected $jsonFactory; protected $response; private $httpResponse; private $jsonSerializer;

public function __construct(
 JsonFactory $jsonFactory,
 ResponseInterface $response,
 HttpResponse $httpResponse = null,
 SerializerInterface $jsonSerializer
) {
 $this->jsonFactory = $jsonFactory;
 $this->response = $response;
 $this->httpResponse = $httpResponse ?: ObjectManager::getInstance()->get(HttpResponse::class);
 $this->jsonSerializer = $jsonSerializer;
}
public function aroundDispatch(
 \Magento\GraphQl\Controller\GraphQl $subject,
 callable $proceed,
 RequestInterface $request
) {
 $content = trim((string)$request->getContent());
 if ($request->isPost()) {
 try {
 $data = $this->jsonSerializer->unserialize($content);
 } catch (\InvalidArgumentException $e) {
 $result = $this->jsonFactory->create();
 $result->setHttpResponseCode(400);
 $result->setData(['error' => 'Invalid JSON in request body']);
 $result->renderResult($this->httpResponse);
 return $this->httpResponse;
 }
 }
 return $proceed($request);
}

}