def list_targets
      #Date is the current date per RFC 2616, section 3.3.1,
      #rfc1123-date format, e.g.: Sun, 22 Apr #2012 08:49:37 GMT.
      date_timestamp = Time.now.httpdate #ruby provides this date format
                                         #with httpdate method
      signature = self.build_signature('/targets', nil, 'GET', date_timestamp)
      raise ArgumentError.new('Signature returned nil. Aborting...') if signature == nil

      authorization_header = "VWS " + @accesskey + ":" +  signature
      begin
        RestClient.get(TARGETS_URL, :'Date' => date_timestamp,
                                    :'Authorization' => authorization_header)
      rescue => e
        e.response
      end
    end
def list_targets
      #Date is the current date per RFC 2616, section 3.3.1,
      #rfc1123-date format, e.g.: Sun, 22 Apr #2012 08:49:37 GMT.
      date_timestamp = Time.now.httpdate #ruby provides this date format
                                         #with httpdate method
      signature = self.build_signature('/targets', nil, 'GET', date_timestamp)
      raise ArgumentError.new('Signature returned nil. Aborting...') if signature == nil

      authorization_header = "VWS " + @accesskey + ":" +  signature
      begin
        RestClient.get(TARGETS_URL, :'Date' => date_timestamp,
                                    :'Authorization' => authorization_header)
      rescue => e
        e.response
      end
    end
Calls the api end point for the list of targets associated with
 server access key and cloud database
 https://developer.vuforia.com/library/articles/Solution/How-To-Get-a-Target-List-for-a-Cloud-Database-Using-the-VWS-API