cowboy/test/handlers/stream_handler_h.erl

%% This module behaves differently depending on a specific header.

-module(stream_handler_h).
-behavior(cowboy_stream).

-export([init/3]).
-export([data/4]).
-export([info/3]).
-export([terminate/3]).
-export([early_error/5]).

-record(state, {
	pid,
	test
}).

init(StreamID, Req, Opts) ->
	Pid = list_to_pid(binary_to_list(cowboy_req:header(<<"x-test-pid">>, Req))),
	Test = binary_to_atom(cowboy_req:header(<<"x-test-case">>, Req), latin1),
	State = #state{pid=Pid, test=Test},
	Pid ! {Pid, self(), init, StreamID, Req, Opts},
	{init_commands(StreamID, Req, State), State}.

init_commands(_, _, State=#state{test=shutdown_on_stream_stop}) ->
	Spawn = init_process(false, State),
	[{headers, 200, #{}}, {spawn, Spawn, 5000}, stop];
init_commands(_, _, State=#state{test=shutdown_on_socket_close}) ->
	Spawn = init_process(false, State),
	[{headers, 200, #{}}, {spawn, Spawn, 5000}];
init_commands(_, _, State=#state{test=shutdown_timeout_on_stream_stop}) ->
	Spawn = init_process(true, State),
	[{headers, 200, #{}}, {spawn, Spawn, 2000}, stop];
init_commands(_, _, State=#state{test=shutdown_timeout_on_socket_close}) ->
	Spawn = init_process(true, State),
	[{headers, 200, #{}}, {spawn, Spawn, 2000}];
init_commands(_, _, _) ->
	[{headers, 200, #{}}].

init_process(TrapExit, #state{pid=Pid}) ->
	Self = self(),
	Spawn = spawn_link(fun() ->
		process_flag(trap_exit, TrapExit),
		Pid ! {Pid, Self, spawned, self()},
		receive {Pid, ready} -> ok after 1000 -> error(timeout) end,
		Self ! {self(), ready},
		receive after 5000 ->
			Pid ! {Pid, Self, still_alive, self()}
		end
	end),
	receive {Spawn, ready} -> ok after 1000 -> error(timeout) end,
	Spawn.

data(StreamID, IsFin, Data, State=#state{pid=Pid}) ->
	Pid ! {Pid, self(), data, StreamID, IsFin, Data, State},
	{[], State}.

info(StreamID, Info, State=#state{pid=Pid}) ->
	Pid ! {Pid, self(), info, StreamID, Info, State},
	{[], State}.

terminate(StreamID, Reason, State=#state{pid=Pid}) ->
	Pid ! {Pid, self(), terminate, StreamID, Reason, State},
	ok.

%% This clause can only test for early errors that reached the required header.
early_error(StreamID, Reason, PartialReq, Resp, Opts) ->
	Pid = list_to_pid(binary_to_list(cowboy_req:header(<<"x-test-pid">>, PartialReq))),
	Pid ! {Pid, self(), early_error, StreamID, Reason, PartialReq, Resp, Opts},
	Resp.