shttp.erl

-module (shttp).
-export ([bench_test_start/0, bench_test_stop/0, start/1, start/2]).




bench_test_start() ->
	Pid = start(8000, fun handle_page/3),
	register(http_server, Pid).
	
bench_test_stop() ->
	bench_test_stop(lists:member( http_server, registered() )).

bench_test_stop(true) ->
	http_server ! shutdown,
	unregister(http_server),
	ok;

bench_test_stop(false) -> ok.



handle_page(Method, Url, Headers) ->
	io_lib:format("Url: ~p<br />Method: ~p", [Url, Method]).



start(Callback) ->
	start(80, Callback).
	
start(Port, Callback) ->
	inets:start(),
	Opts = [{active, false}, 
			binary, 
			{backlog, 100},
			{packet, raw},
			{reuseaddr, true}],
	{ok, Socket} = gen_tcp:listen(Port, Opts),
	Acceptor = spawn(fun() -> accept(Socket, Callback) end),
	spawn(fun() -> control(Socket, Acceptor) end).
	
control(Socket, Acceptor) ->
	receive
		shutdown ->
			exit(Acceptor, shutdown),
			gen_tcp:close(Socket);
		{callback, Callback} ->
			exit(Acceptor, new_callback),
			accept(Socket, Callback);
		X ->
			io:format("Controller got: ~p~n", [X])
	end,
	control(Socket, Acceptor).

accept(Socket, Callback) ->
	case gen_tcp:accept(Socket) of
		{ok, Connection} -> spawn(fun() -> receive_data(Connection, Callback) end),
							accept(Socket, Callback);
		{error, closed}  -> ok;
		Error			 -> io:format("Weird Error: ~p~n", [Error])
	end.
	
receive_data(Connection, Callback) ->
	case gen_tcp:recv(Connection, 0) of
		{ok, Data} ->
			spawn(fun() -> handle_http(binary_to_list(Data), Connection, Callback) end);
		Error ->
			Error
	end,
	receive_data(Connection, Callback).
	
handle_http(Request, Connection, Callback) ->
	[FirstLine | Rest] = string:tokens(Request, "\r\n"),
	[Method, Path, Version] = string:tokens(FirstLine, " "),
	ParsedHeaders = string_to_headers(string:join(Rest, "\r\n")),
	Headers = lists:append([ParsedHeaders,
				[{"method", Method},
				 {"url", lists:concat(["http://", proplists:get_value("host", ParsedHeaders), Path])},
				 {"version", Version}]
				]),
	Response = Callback(Method, "/" ++ Path, Headers),
	http_response(Response, Connection),
	ok.
	
http_response({Code, Body}, Connection) ->
	Length = integer_to_list(length(Body)),
	Response = lists:concat(["HTTP/1.1 ", integer_to_list(Code), " OK\r\n",
				"Content-Length: ", Length, "\r\n\r\n", Body]),
	gen_tcp:send(Connection, Response),
	gen_tcp:close(Connection);
	
http_response(Body, Connection) ->
	Length = integer_to_list(length(Body)),
	Response = lists:concat(["HTTP/1.1 200 OK\r\n",
				"Content-Length: ", Length, "\r\n\r\n", Body]),
	gen_tcp:send(Connection, Response),
	gen_tcp:close(Connection).
	
headers_to_string(Headers) ->
	Seperated = lists:map(fun(Pair) ->
		{Key, Value} = Pair,
		string:join([Key, Value], ": ")
	end, Headers),
	string:join(Seperated, "\r\n") ++ "\r\n".


string_to_headers(String) ->
	Lines = string:tokens(String, "\r\n"),
	KeyList = lists:map(fun(Elem) ->
		ColonIndex = string:chr(Elem, $:),
		{ string:to_lower(string:substr(Elem, 1, ColonIndex - 1)),
		  string:substr(Elem, ColonIndex + 2, length(Elem)) }
	end, Lines),
	KeyList.