Scalr\Service\Aws::getMd5Base64Digest PHP Method

    public static function getMd5Base64Digest($string)
    {
        return base64_encode(pack('H*', md5($string)));
    }

 /**
  * Calls Amazon web service method.
  *
  * It ensures execution of the certain AWS action by transporting the request
  * and receiving response.
  *
  * @param     string    $action           REST METHOD (GET|PUT|DELETE|HEAD etc).
  * @param     array     $options          An options array. It's used to send headers for the HTTP request.
  *                                        extra options: _subdomain, _putData, _putFile
  * @param     string    $path    optional A relative path.
  * @return    ClientResponseInterface
  * @throws    ClientException
  */
 public function call($action, $options, $path = '/')
 {
     $httpRequest = $this->createRequest();
     $httpMethod = $action ?: 'GET';
     if (substr($path, 0, 1) !== '/') {
         $path = '/' . $path;
     }
     $this->lastApiCall = null;
     $eventObserver = $this->getAws()->getEventObserver();
     if ($eventObserver && $eventObserver->isSubscribed(EventType::EVENT_SEND_REQUEST)) {
         foreach (debug_backtrace() as $arr) {
             if (empty($arr['class']) || !preg_match("/\\\\Service\\\\Aws\\\\.+Api\$/", $arr['class']) || $arr['type'] !== '->') {
                 continue;
             }
             $this->lastApiCall = ucfirst($arr['function']);
             break;
         }
     }
     //Wipes out extra options from headers and moves them to separate array.
     //It also collects an x-amz headers.
     $extraOptions = ['region' => null];
     foreach ($options as $key => $val) {
         if (substr($key, 0, 1) === '_') {
             $extraOptions[substr($key, 1)] = $val;
             unset($options[$key]);
         }
     }
     if (!isset($options['Host'])) {
         $options['Host'] = (isset($extraOptions['subdomain']) ? $extraOptions['subdomain'] . '.' : '') . $this->url;
     }
     if (strpos($options['Host'], 'http') === 0) {
         $arr = parse_url($options['Host']);
         $scheme = $arr['scheme'];
         $options['Host'] = $arr['host'] . (isset($arr['port']) ? ':' . $arr['port'] : '');
         $path = (!empty($arr['path']) && $arr['path'] != '/' ? rtrim($arr['path'], '/') : '') . $path;
     } else {
         $scheme = 'https';
     }
     if ($httpMethod === 'PUT' || $httpMethod === 'POST') {
         if (!empty($extraOptions['putData'])) {
             $httpRequest->append($extraOptions['putData']);
             $options['Content-Md5'] = Aws::getMd5Base64Digest($extraOptions['putData']);
         } elseif (!empty($extraOptions['putFile'])) {
             $httpRequest->addFiles([$extraOptions['putFile']]);
             $options['Content-Md5'] = Aws::getMd5Base64DigestFile($extraOptions['putFile']);
         }
     }
     $httpRequest->setRequestUrl($scheme . '://' . $options['Host'] . $path);
     $httpRequest->setRequestMethod($httpMethod);
     $httpRequest->addHeaders($options);
     if (true) {
         $this->signRequestV4($httpRequest, !empty($extraOptions['region']) ? $extraOptions['region'] : null, empty($extraOptions['putFile']) ? null : $extraOptions['putFile']);
     } else {
         $this->signRequestV3($httpRequest, isset($extraOptions['subdomain']) ? $extraOptions['subdomain'] : null);
     }
     $response = $this->tryCall($httpRequest);
     if ($this->getAws() && $this->getAws()->getDebug()) {
         echo "\n", "{$httpRequest}\n", "{$response->getResponse()}\n";
     }
     return $response;
 }