Thank you very much guys. One more thing, I'm not sure I understand what does the string parameter (in this case "user") does in

@before!authenticate("user")

and what's the 'result' parameter of addBrackets?

string addBrackets(string result /* THIS ONE */, HTTPServerRequest, HTTPServerResponse)
{
	return "{" ~ result ~ "}";
}

Is this the generated response string?

Thanks again :)