Psr7Middlewares\Middleware\FormatNegotiator::getFromHeader PHP Méthode

    private function getFromHeader(ServerRequestInterface $request)
    {
        $headers = call_user_func_array('array_merge', array_column($this->formats, 1));
        $mime = $this->negotiateHeader($request->getHeaderLine('Accept'), new Negotiator(), $headers);
        if ($mime !== null) {
            foreach ($this->formats as $format => $data) {
                if (in_array($mime, $data[1], true)) {
                    return $format;
                }
            }
        }
    }