/**
  *  Lists the briefs under a particular feed.
  *
  * @param int feedId
  * @param int $offset offset to skip
  * @param int $limit The limit to apply to the list (maximum 100)
  * @param array $properties array of properties to add to querystring
  * @param array $fields array of fields to add to querystring
  * @returnBriefList
  */
 private function ListBriefsForFeed($feedId, $offset, $limit, $properties, $fields)
 {
     $uri = $this->GetUri($feedId, "feedId", "xml", $properties, $fields, $offset, $limit);
     $uri = "http://" . $this->credentials->getPublicKey() . ":" . $this->credentials->getSecretKey() . "@" . str_replace("http://", "", $uri);
     $xmlString = AdferoHelpers::GetXMLFromUri($uri);
     $briefs = $this->ListBriefsFromXmlString($xmlString);
     $briefs->limit = $limit;
     $briefs->offset = $offset;
     return $briefs;
 }
 /**
  * Gets the response from the api in string format
  * 
  * @param int $id
  * @param array $properties array of properties to add to querystring
  * @param array $fields array of fields to add to querystring
  * @param string $format either "xml" or "json"
  * @return string
  * @throws InvalidArgumentException 
  */
 private function GetArticleRaw($id, $properties, $fields, $format)
 {
     switch ($format) {
         case "xml":
             $uri = $this->GetUri($id, null, "xml", $properties, $fields, null, null);
             break;
         case "json":
             $uri = $this->GetUri($id, null, "json", $properties, $fields, null, null);
             break;
         default:
             throw new InvalidArgumentException($format . 'format not supported');
             break;
     }
     $uri = "http://" . $this->credentials->getPublicKey() . ":" . $this->credentials->getSecretKey() . "@" . str_replace("http://", "", $uri);
     return AdferoHelpers::GetRawResponse($uri);
 }