<?PHP

class Something
{
  
  public static function ReadExternal($data)
  {
		$content = explode( " ", base64_decode($data), 4);

    if (count($content) == 4)
    {
	  	$hmac = Utility::calculateHMAC("THE MAGIC NUMBER", $content[0] . " " . $content[1] . " " . $content[2]);

	  	if (base64_encode($hmac) === $content[3])
	  	{
	  	  // Set this donation object up!
	  	  $instance = new Something(null);
	  	  
	  	  $instance->UserId = $content[1];
	  	  $instance->ProjectId = $content[2];

				return $instance;
	  	}      
	  	else
	  	{
		    throw new SomethingException("HMAC did not match.");
		  }
    }
    else
    {
      throw new SomethingException("Not enough data.");
    }
    
    return null;
  }
  
  public function WriteExternal()
  {
    $data = $this->UserId . " " . $this->ProjectId;
    $salt = uniqid(rand(), true);
    $message = $salt . " " . $data;
    $hmac =  Utility::calculateHMAC(Keys::_SECRET,$message);
    
    $output = $message . " " . base64_encode($hmac);
    
    return base64_encode($output);
  }
  
}

?>