This module is responsible for all the different return types a controller have. Nova is constructed in such way that it's really easy to extend it by using handlers. A handler is basically a module consisting of a function of arity 4. We will show an example of this.

If you implement the following module:

-module(my_handler). -export([init/0, handle_console]).

init() -> nova_handlers:register_handler(console, {my_handler, handle_console}).

handle_console({console, Format, Args}, {Module, Function}, State) -> io:format("~n=====================~n", []). io:format("~p:~p was called.~n", []), io:format("State: ~p~n", [State]), io:format(Format, Args), io:format("~n=====================~n", []), {ok, 200, #{}, EmptyBinary}.

The init/0 should be invoked from your applications supervisor and will register the module my_handler as handler of the return type {console, Format, Args}. This means that you can return this tuple in a controller which invokes my_handler:handle_console/4.

A handler can return two different types

{ok, StatusCode, Headers, Body} - This will return a proper reply to the requester.