kronostechnologies/graphql-framework

<?php


namespace Kronos\GraphQLFramework\EntryPoint;


use GuzzleHttp\Psr7\Response;
use Kronos\GraphQLFramework\EntryPoint\Exception\HttpQueryRequiredException;
use Kronos\GraphQLFramework\EntryPoint\Exception\HttpVariablesIncorrectlyDefinedException;
use Kronos\GraphQLFramework\Exception\ClientDisplayableExceptionInterface;
use Kronos\GraphQLFramework\Executor\Executor;
use Kronos\GraphQLFramework\FrameworkConfiguration;
use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ServerRequestInterface;
use function array_key_exists;

class HttpEntryPoint
{
    /**
     * @var FrameworkConfiguration
     */
    protected $configuration;

    public function __construct(FrameworkConfiguration $configuration)
    {
        $this->configuration = $configuration;
    }

    /**
     * @param ServerRequestInterface $request
     * @return ResponseInterface
     * @throws \HttpException
     * @throws HttpQueryRequiredException
     * @throws HttpVariablesIncorrectlyDefinedException
     */
    public function executeRequest(ServerRequestInterface $request)
    {
        if ($request->getMethod() === 'GET') {
            return $this->executeGetRequest($request);
        } else if ($request->getMethod() === 'POST') {
            return $this->executePostRequest($request);
        } else {
            throw new \HttpException("Unsupported method {$request->getMethod()} for GraphQL. Only GET and POST are allowed.", 405);
        }
    }

    /**
     * @param ServerRequestInterface $request
     * @return ResponseInterface
     * @throws HttpQueryRequiredException
     * @throws HttpVariablesIncorrectlyDefinedException
     */
    protected function executeGetRequest(ServerRequestInterface $request)
    {
        $queryParams = $request->getQueryParams();

        if (!array_key_exists('query', $queryParams)) {
            throw new HttpQueryRequiredException('GET');
        }

        $variables = array_key_exists('variables', $queryParams) ? $queryParams['variables'] : null;
        $query = $queryParams['query'];

        if (strpos($query, "query ") !== 0) {
            $query = "query " . $query;
        }

        $areVariablesSet = ($variables !== null && trim($variables) !== "");

        if ($areVariablesSet) {
            $variables = json_decode($variables, true);

            if ($variables === null) {
                throw new HttpVariablesIncorrectlyDefinedException('GET');
            }
        } else {
            $variables = [];
        }

        return $this->executeQueryAndGetResponse($query, $variables);
    }

    /**
     * @param ServerRequestInterface $request
     * @return ResponseInterface
     * @throws HttpQueryRequiredException
     * @throws HttpVariablesIncorrectlyDefinedException
     */
    protected function executePostRequest(ServerRequestInterface $request)
    {
        $parsedBody = json_decode($request->getBody()->getContents(), true);

        if ($parsedBody === null || !array_key_exists('query', $parsedBody)) {
            throw new HttpQueryRequiredException('POST');
        }

        $variables = array_key_exists('variables', $parsedBody) ? $parsedBody['variables'] : null;
        $query = $parsedBody['query'];

        $areVariablesSet = ($variables !== null && !empty($variables));

        if ($areVariablesSet) {
            if (is_string($variables)) {
                $variables = json_decode($variables, true);
            }

            if ($variables === null) {
                throw new HttpVariablesIncorrectlyDefinedException('POST');
            }
        } else {
            $variables = [];
        }

        return $this->executeQueryAndGetResponse($query, $variables);
    }

    /**
     * Useful for mocking.
     *
     * @return Executor
     */
    protected function getExecutor()
    {
        return new Executor($this->configuration);
    }

    /**
     * @param string $queryString
     * @param array $variables
     * @return ResponseInterface
     */
    protected function executeQueryAndGetResponse($queryString, array $variables)
    {
        $executor = $this->getExecutor();

        $result = $executor->executeQuery($queryString, $variables);

        if ($result->hasError()) {
            $underlyingException = $result->getUnderlyingException();
            if ($underlyingException instanceof ClientDisplayableExceptionInterface) {
                $statusCode = $underlyingException->getClientHttpStatusCode();
            } else {
                $statusCode = 500;
            }
        } else {
            $statusCode = 200;
        }
        $headers = [];

        return new Response($statusCode, $headers, $result->getResponseText());
    }
}