add websockets example

stevenproctor · Sep 30, 2012 · a74fbd7 · a74fbd7
1 parent 981ea35
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diff --git a/examples/websockets/README.md b/examples/websockets/README.md
@@ -0,0 +1,5 @@
+Websockets example
+==================
+
+$ rebar compile
+$ ./start.sh
diff --git a/examples/websockets/src/websockets.app.src b/examples/websockets/src/websockets.app.src
@@ -0,0 +1,15 @@
+%% Feel free to use, reuse and abuse the code in this file.
+
+{application, websockets, [
+	{description, "Cowboy Websockets example."},
+	{vsn, "1"},
+	{modules, []},
+	{registered, []},
+	{applications, [
+		kernel,
+		stdlib,
+		cowboy
+	]},
+	{mod, {websockets_app, []}},
+	{env, []}
+]}.
diff --git a/examples/websockets/src/websockets.erl b/examples/websockets/src/websockets.erl
@@ -0,0 +1,11 @@
+-module(websockets).
+
+%% API.
+-export([start/0]).
+
+%% API.
+
+start() ->
+	ok = application:start(ranch),
+	ok = application:start(cowboy),
+	ok = application:start(websockets).
diff --git a/examples/websockets/src/websockets_app.erl b/examples/websockets/src/websockets_app.erl
@@ -0,0 +1,23 @@
+%% @private
+-module(websockets_app).
+-behaviour(application).
+
+%% API.
+-export([start/2]).
+-export([stop/1]).
+
+%% API.
+
+start(_Type, _Args) ->
+	Dispatch = [
+		{'_', [
+			{[], websockets_handler, []}
+		]}
+	],
+	{ok, _} = cowboy:start_http(http, 100, [{port, 8080}], [
+		{dispatch, Dispatch}
+	]),
+	websockets_sup:start_link().
+
+stop(_State) ->
+	ok.
diff --git a/examples/websockets/src/websockets_handler.erl b/examples/websockets/src/websockets_handler.erl
@@ -0,0 +1,88 @@
+-module(websockets_handler).
+-behaviour(cowboy_http_handler).
+-behaviour(cowboy_websocket_handler).
+
+-export([init/3, handle/2, terminate/2]).
+
+-export([websocket_init/3, websocket_handle/3,
+	websocket_info/3, websocket_terminate/3]).
+
+init({_Any, http}, Req, []) ->
+	case cowboy_req:header(<<"upgrade">>, Req) of
+		{undefined, Req2} -> {ok, Req2, undefined};
+		{<<"websocket">>, _Req2} -> {upgrade, protocol, cowboy_websocket}
+	end.
+
+handle(Req, State) ->
+	{ok, Req2} = cowboy_req:reply(200, [{<<"Content-Type">>, <<"text/html">>}],
+%% HTML code taken from misultin's example file.
+<<"<html>
+<head>
+<script type=\"text/javascript\">
+function addStatus(text){
+	var date = new Date();
+	document.getElementById('status').innerHTML
+		= document.getElementById('status').innerHTML
+		+ date + \": \" + text + \"<br/>\";
+}
+function ready(){
+	if (\"MozWebSocket\" in window) {
+		WebSocket = MozWebSocket;
+	}
+	if (\"WebSocket\" in window) {
+		// browser supports websockets
+		var ws = new WebSocket( (window.location.protocol == 'http:' 
+								 ? 'ws://' : 'wss://') + 
+								window.location.host + '/');
+		ws.onopen = function() {
+			// websocket is connected
+			addStatus('websocket connected!');
+			// send hello data to server.
+			var msg = 'hello hello hello what\\'s going on \\'ere then?';
+			ws.send(msg);
+			addStatus('sent message to server: ' + msg);
+		};
+		ws.onmessage = function (evt) {
+			var receivedMsg = evt.data;
+			addStatus(\"server sent the following: '\" + receivedMsg + \"'\");
+		};
+		ws.onclose = function() {
+			// websocket was closed
+			addStatus(\"websocket was closed\");
+		};
+	} else {
+		// browser does not support websockets
+		addStatus(\"sorry, your browser does not support websockets.\");
+	}
+}
+</script>
+</head>
+<body onload=\"\">
+Hi!
+<input type=\"button\" onclick=\"ready();\" value=\"click\"/>
+<div id=\"status\"></div>
+</body>
+</html>">>, Req),
+	{ok, Req2, State}.
+
+terminate(_Req, _State) ->
+	ok.
+
+websocket_init(_Any, Req, []) ->
+	timer:send_interval(1000, tick),
+	Req2 = cowboy_req:compact(Req),
+	{ok, Req2, undefined, hibernate}.
+
+websocket_handle({text, Msg}, Req, State) ->
+	{reply, {text, << "You said: ", Msg/binary >>}, Req, State, hibernate};
+websocket_handle(_Any, Req, State) ->
+	{ok, Req, State}.
+
+%% send some repeated text to show compression at work if anyone is counting
+websocket_info(tick, Req, State) ->
+	{reply, {text, <<"badger badger badger badger badger badger badger">>}, Req, State, hibernate};
+websocket_info(_Info, Req, State) ->
+	{ok, Req, State, hibernate}.
+
+websocket_terminate(_Reason, _Req, _State) ->
+	ok.
diff --git a/examples/websockets/src/websockets_sup.erl b/examples/websockets/src/websockets_sup.erl
@@ -0,0 +1,21 @@
+%% @private
+-module(websockets_sup).
+-behaviour(supervisor).
+
+%% API.
+-export([start_link/0]).
+
+%% supervisor.
+-export([init/1]).
+
+%% API.
+
+-spec start_link() -> {ok, pid()}.
+start_link() ->
+	supervisor:start_link({local, ?MODULE}, ?MODULE, []).
+
+%% supervisor.
+
+init([]) ->
+	Procs = [],
+	{ok, {{one_for_one, 10, 10}, Procs}}.
diff --git a/examples/websockets/start.sh b/examples/websockets/start.sh
@@ -0,0 +1,3 @@
+#!/bin/sh
+erl -pa ebin ../../ebin ../../deps/*/ebin -boot start_sasl -s websockets \
+	-eval "io:format(\"Point your browser at http://localhost:8080~n\")."