version: 0.1.0

+ ws server at "/" and port 11000
+ simple ws handler casting to wsbus

src/wsio_app.erl

@@ -0,0 +1,16 @@
+-module(wsio_app).
+-behaviour(application).
+
+-export([start/2]).
+-export([stop/1]).
+
+start(_Type, _Args) ->
+  Routes = [{"/", wsio_handler, none}],
+  Dispatch = cowboy_router:compile([{'_', Routes}]),
+  {ok, _} = cowboy:start_clear(httpd, [inet, {port, 11000}],
+                               #{env => #{dispatch => Dispatch}}
+                               ),  
+  wsio_sup:start_link().
+
+stop(_State) ->
+  ok.

src/wsio_handler.erl

@@ -0,0 +1,48 @@
+-module(wsio_handler).
+
+-export([init/2]).
+-export([websocket_handle/2]).
+-export([websocket_init/1]).
+-export([websocket_info/2]).
+
+-define(TTL_PING, 10000).
+
+init(R, _) ->
+  {cowboy_websocket, R, #{}}.
+
+websocket_init(S) ->
+  Ref = st:lookup(wsbus),
+  {ok, S#{wsbus => nil, ref_wsbus => Ref}}.
+
+websocket_handle({text, <<Data/binary>>}, S) ->
+  case jsx:is_json(Data) of
+    true ->
+      websocket_handle({json, jsx:decode(Data)}, S);
+    false ->
+      {ok, S}
+  end;
+websocket_handle({json, #{<<"ref">> := Ref}}, #{wsbus := nil} = S) ->
+  {[{text, jsx:encode(#{<<"ref">> => Ref, <<"wsio-code">> => 0})}], S};
+websocket_handle({json, Data}, #{wsbus := BUS} = S) ->
+  gen_server:cast(BUS, {call, Data, self()}),
+  {ok, S};
+websocket_handle(_, State) ->
+  {ok, State}.
+
+websocket_info(close, S) ->
+  {[close], S};
+websocket_info(ping, S) ->
+  erlang:send_after(?TTL_PING, self(), ping),
+  {[ping], S};
+websocket_info({send, #{} = Map}, S) ->
+  {[{text, jsx:encode(Map)}], S};
+websocket_info({send, <<Bin/binary>>}, S) ->
+  {[{text, Bin}], S};
+websocket_info({send, List}, S) when is_list(List) ->
+  {List, S};
+websocket_info({_, {Ref, {error, notfound}}}, #{ref_wsbus := Ref} = S) ->
+  {ok, S#{ref_wsbus => st:lookup(wsbus)}};
+websocket_info({_, {Ref, {ok, PID}}}, #{ref_wsbus := Ref} = S) ->
+  {ok, maps:remove(ref_wsbus, S#{wsbus => PID})};
+websocket_info(_, S) ->
+  {ok, S}.

src/wsio_sup.erl

@@ -0,0 +1,12 @@
+-module(wsio_sup).
+-behaviour(supervisor).
+
+-export([start_link/0]).
+-export([init/1]).
+
+start_link() ->
+  supervisor:start_link({local, ?MODULE}, ?MODULE, []).
+
+init([]) ->
+  Procs = [],
+  {ok, {{one_for_one, 1, 5}, Procs}}.