/**
  * Save AT and timestamp in file
  *
  * @param string $access_token
  * @param int    $timestamp
  *
  * @return bool
  */
 private function save($access_token, $timestamp)
 {
     unset($this->runtime_file_content);
     $bytes = @file_put_contents($this->getFilePath(), json_encode(array('a' => $access_token, 'e' => $timestamp)));
     if ($bytes === false) {
         // fatal log will throw an exception
         $this->logger->fatal(__CLASS__, 'store', sprintf('Unable to store access token in %s', $this->getFilePath()));
     }
     $this->logger->debug(__CLASS__, 'store', sprintf('Access token stored in %s', $this->getFilePath()));
     return true;
 }
 /**
  * @return array|string
  * @throws \MicrosoftTranslator\Exception
  */
 private function generateAndStoreNewAccessToken()
 {
     $url = trim($this->auth_base_url, "/ \t\n\r\v");
     $access_token = null;
     $auth = array('grant_type' => 'client_credentials', 'client_id' => $this->api_client_id, 'client_secret' => $this->api_client_secret, 'scope' => $this->api_client_scope);
     $result = $this->http->post($url, null, $auth, null);
     if (Http::isRequestOk($result)) {
         $result['http_body'] = json_decode($result['http_body'], true);
         if (!isset($result['http_body']['access_token'])) {
             throw new Exception('Access token not found in response');
         }
         if (!is_string($result['http_body']['access_token'])) {
             throw new Exception('Access token found in response but it is not a string');
         }
         $access_token = strval(@$result['http_body']['access_token']);
         $expires_in = @(int) $result['http_body']['expires_in'];
         $this->logger->debug(__CLASS__, 'oauth', sprintf('New access_token generated %s...', substr($access_token, 0, 10)));
         $this->guard->storeAccessTokenForSeconds($access_token, $expires_in);
     } else {
         $this->logger->fatal(__CLASS__, 'oauth', 'Unable to generate a new access token : ' . json_encode($result));
     }
     return $access_token;
 }