class UpdateTestController

class UpdateTestController extends ControllerBase {
    
    /**
     * Displays an Error 503 (Service unavailable) page.
     *
     * @return \Symfony\Component\HttpFoundation\Response
     *   Returns the response with a special header.
     */
    public function updateError() {
        $response = new Response();
        $response->setStatusCode(503);
        $response->headers
            ->set('Status', '503 Service unavailable');
        return $response;
    }
    
    /**
     * Page callback: Prints mock XML for the Update Manager module.
     *
     * The specific XML file to print depends on two things: the project we're
     * trying to fetch data for, and the desired "availability scenario" for that
     * project which we're trying to test. Before attempting to fetch this data (by
     * checking for updates on the available updates report), callers need to define
     * the 'update_test_xml_map' variable as an array, keyed by project name,
     * indicating which availability scenario to use for that project.
     *
     * @param string $project_name
     *   The project short name the update manager is trying to fetch data for (the
     *   fetch URLs are of the form: [base_url]/[project_name]/[core_version]).
     * @param string $version
     *   The version of Drupal core.
     *
     * @return \Symfony\Component\HttpFoundation\BinaryFileResponse|Response
     *   A BinaryFileResponse object containing the content of the XML release file
     *   for the specified project if one is available; a Response object with no
     *   content otherwise.
     */
    public function updateTest($project_name, $version) {
        $xml_map = $this->config('update_test.settings')
            ->get('xml_map');
        if (isset($xml_map[$project_name])) {
            $availability_scenario = $xml_map[$project_name];
        }
        elseif (isset($xml_map['#all'])) {
            $availability_scenario = $xml_map['#all'];
        }
        else {
            // The test didn't specify a project nor '#all' (for all extensions on the
            // system). So, we default to a file we know won't exist, so at least
            // we'll get an empty xml response instead of a bunch of Drupal page
            // output.
            $availability_scenario = '#broken#';
        }
        $file = __DIR__ . "/../../../../fixtures/release-history/{$project_name}.{$availability_scenario}.xml";
        $headers = [
            'Content-Type' => 'text/xml; charset=utf-8',
        ];
        if (!is_file($file)) {
            // Return an empty response.
            return new Response('', 200, $headers);
        }
        return new BinaryFileResponse($file, 200, $headers);
    }

}