PrivateBin\Request::_detectJsonRequest PHP Метод

    private function _detectJsonRequest()
    {
        $hasAcceptHeader = array_key_exists('HTTP_ACCEPT', $_SERVER);
        $acceptHeader = $hasAcceptHeader ? $_SERVER['HTTP_ACCEPT'] : '';
        // simple cases
        if (array_key_exists('HTTP_X_REQUESTED_WITH', $_SERVER) && $_SERVER['HTTP_X_REQUESTED_WITH'] == 'JSONHttpRequest' || $hasAcceptHeader && strpos($acceptHeader, self::MIME_JSON) !== false && strpos($acceptHeader, self::MIME_HTML) === false && strpos($acceptHeader, self::MIME_XHTML) === false) {
            return true;
        }
        // advanced case: media type negotiation
        $mediaTypes = array();
        if ($hasAcceptHeader) {
            $mediaTypeRanges = explode(',', trim($acceptHeader));
            foreach ($mediaTypeRanges as $mediaTypeRange) {
                if (preg_match('#(\\*/\\*|[a-z\\-]+/[a-z\\-+*]+(?:\\s*;\\s*[^q]\\S*)*)(?:\\s*;\\s*q\\s*=\\s*(0(?:\\.\\d{0,3})|1(?:\\.0{0,3})))?#', trim($mediaTypeRange), $match)) {
                    if (!isset($match[2])) {
                        $match[2] = '1.0';
                    } else {
                        $match[2] = (string) floatval($match[2]);
                    }
                    if (!isset($mediaTypes[$match[2]])) {
                        $mediaTypes[$match[2]] = array();
                    }
                    $mediaTypes[$match[2]][] = strtolower($match[1]);
                }
            }
            krsort($mediaTypes);
            foreach ($mediaTypes as $acceptedQuality => $acceptedValues) {
                if ($acceptedQuality === 0.0) {
                    continue;
                }
                foreach ($acceptedValues as $acceptedValue) {
                    if (strpos($acceptedValue, self::MIME_HTML) === 0 || strpos($acceptedValue, self::MIME_XHTML) === 0) {
                        return false;
                    } elseif (strpos($acceptedValue, self::MIME_JSON) === 0) {
                        return true;
                    }
                }
            }
        }
        return false;
    }