%% Copyright (c) 2011, Loïc Hoguin <[email protected]>
%% Copyright (c) 2011, Anthony Ramine <[email protected]>
%%
%% Permission to use, copy, modify, and/or distribute this software for any
%% purpose with or without fee is hereby granted, provided that the above
%% copyright notice and this permission notice appear in all copies.
%%
%% THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
%% WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
%% MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
%% ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
%% WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
%% ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
%% OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
%% @doc HTTP protocol handler.
%%
%% The available options are:
%% <dl>
%% <dt>dispatch</dt><dd>The dispatch list for this protocol.</dd>
%% <dt>max_empty_lines</dt><dd>Max number of empty lines before a request.
%% Defaults to 5.</dd>
%% <dt>timeout</dt><dd>Time in milliseconds before an idle
%% connection is closed. Defaults to 5000 milliseconds.</dd>
%% </dl>
%%
%% Note that there is no need to monitor these processes when using Cowboy as
%% an application as it already supervises them under the listener supervisor.
%%
%% @see cowboy_dispatcher
%% @see cowboy_http_handler
-module(cowboy_http_protocol).
-behaviour(cowboy_protocol).
-export([start_link/4]). %% API.
-export([init/4, parse_request/1, handler_loop/3]). %% FSM.
-include("include/http.hrl").
-include_lib("eunit/include/eunit.hrl").
-record(state, {
listener :: pid(),
socket :: inet:socket(),
transport :: module(),
dispatch :: cowboy_dispatcher:dispatch_rules(),
handler :: {module(), any()},
req_empty_lines = 0 :: integer(),
max_empty_lines :: integer(),
max_line_length :: integer(),
timeout :: timeout(),
buffer = <<>> :: binary(),
hibernate = false :: boolean(),
loop_timeout = infinity :: timeout(),
loop_timeout_ref :: undefined | reference()
}).
%% API.
%% @doc Start an HTTP protocol process.
-spec start_link(pid(), inet:socket(), module(), any()) -> {ok, pid()}.
start_link(ListenerPid, Socket, Transport, Opts) ->
Pid = spawn_link(?MODULE, init, [ListenerPid, Socket, Transport, Opts]),
{ok, Pid}.
%% FSM.
%% @private
-spec init(pid(), inet:socket(), module(), any()) -> ok | none().
init(ListenerPid, Socket, Transport, Opts) ->
Dispatch = proplists:get_value(dispatch, Opts, []),
MaxEmptyLines = proplists:get_value(max_empty_lines, Opts, 5),
MaxLineLength = proplists:get_value(max_line_length, Opts, 4096),
Timeout = proplists:get_value(timeout, Opts, 5000),
receive shoot -> ok end,
wait_request(#state{listener=ListenerPid, socket=Socket, transport=Transport,
dispatch=Dispatch, max_empty_lines=MaxEmptyLines,
max_line_length=MaxLineLength, timeout=Timeout}).
%% @private
-spec parse_request(#state{}) -> ok | none().
%% We limit the length of the Request-line to MaxLength to avoid endlessly
%% reading from the socket and eventually crashing.
parse_request(State=#state{buffer=Buffer, max_line_length=MaxLength}) ->
case erlang:decode_packet(http_bin, Buffer, []) of
{ok, Request, Rest} -> request(Request, State#state{buffer=Rest});
{more, _Length} when byte_size(Buffer) > MaxLength ->
error_terminate(413, State);
{more, _Length} -> wait_request(State);
{error, _Reason} -> error_terminate(400, State)
end.
-spec wait_request(#state{}) -> ok | none().
wait_request(State=#state{socket=Socket, transport=Transport,
timeout=T, buffer=Buffer}) ->
case Transport:recv(Socket, 0, T) of
{ok, Data} -> parse_request(State#state{
buffer= << Buffer/binary, Data/binary >>});
{error, _Reason} -> terminate(State)
end.
-spec request({http_request, http_method(), http_uri(),
http_version()}, #state{}) -> ok | none().
%% @todo We probably want to handle some things differently between versions.
request({http_request, _Method, _URI, Version}, State)
when Version =/= {1, 0}, Version =/= {1, 1} ->
error_terminate(505, State);
%% @todo We need to cleanup the URI properly.
request({http_request, Method, {abs_path, AbsPath}, Version},
State=#state{socket=Socket, transport=Transport}) ->
{Path, RawPath, Qs} = cowboy_dispatcher:split_path(AbsPath),
ConnAtom = version_to_connection(Version),
parse_header(#http_req{socket=Socket, transport=Transport,
connection=ConnAtom, method=Method, version=Version,
path=Path, raw_path=RawPath, raw_qs=Qs}, State);
request({http_request, Method, '*', Version},
State=#state{socket=Socket, transport=Transport}) ->
ConnAtom = version_to_connection(Version),
parse_header(#http_req{socket=Socket, transport=Transport,
connection=ConnAtom, method=Method, version=Version,
path='*', raw_path= <<"*">>, raw_qs= <<>>}, State);
request({http_request, _Method, _URI, _Version}, State) ->
error_terminate(501, State);
request({http_error, <<"\r\n">>},
State=#state{req_empty_lines=N, max_empty_lines=N}) ->
error_terminate(400, State);
request({http_error, <<"\r\n">>}, State=#state{req_empty_lines=N}) ->
parse_request(State#state{req_empty_lines=N + 1});
request(_Any, State) ->
error_terminate(400, State).
-spec parse_header(#http_req{}, #state{}) -> ok | none().
parse_header(Req, State=#state{buffer=Buffer, max_line_length=MaxLength}) ->
case erlang:decode_packet(httph_bin, Buffer, []) of
{ok, Header, Rest} -> header(Header, Req, State#state{buffer=Rest});
{more, _Length} when byte_size(Buffer) > MaxLength ->
error_terminate(413, State);
{more, _Length} -> wait_header(Req, State);
{error, _Reason} -> error_terminate(400, State)
end.
-spec wait_header(#http_req{}, #state{}) -> ok | none().
wait_header(Req, State=#state{socket=Socket,
transport=Transport, timeout=T, buffer=Buffer}) ->
case Transport:recv(Socket, 0, T) of
{ok, Data} -> parse_header(Req, State#state{
buffer= << Buffer/binary, Data/binary >>});
{error, timeout} -> error_terminate(408, State);
{error, closed} -> terminate(State)
end.
-spec header({http_header, integer(), http_header(), any(), binary()}
| http_eoh, #http_req{}, #state{}) -> ok | none().
header({http_header, _I, 'Host', _R, RawHost}, Req=#http_req{
transport=Transport, host=undefined}, State) ->
RawHost2 = cowboy_bstr:to_lower(RawHost),
case catch cowboy_dispatcher:split_host(RawHost2) of
{Host, RawHost3, undefined} ->
Port = default_port(Transport:name()),
dispatch(fun parse_header/2, Req#http_req{
host=Host, raw_host=RawHost3, port=Port,
headers=[{'Host', RawHost3}|Req#http_req.headers]}, State);
{Host, RawHost3, Port} ->
dispatch(fun parse_header/2, Req#http_req{
host=Host, raw_host=RawHost3, port=Port,
headers=[{'Host', RawHost3}|Req#http_req.headers]}, State);
{'EXIT', _Reason} ->
error_terminate(400, State)
end;
%% Ignore Host headers if we already have it.
header({http_header, _I, 'Host', _R, _V}, Req, State) ->
parse_header(Req, State);
header({http_header, _I, 'Connection', _R, Connection},
Req=#http_req{headers=Headers}, State) ->
Req2 = Req#http_req{headers=[{'Connection', Connection}|Headers]},
{ConnTokens, Req3}
= cowboy_http_req:parse_header('Connection', Req2),
ConnAtom = cowboy_http:connection_to_atom(ConnTokens),
parse_header(Req3#http_req{connection=ConnAtom}, State);
header({http_header, _I, Field, _R, Value}, Req, State) ->
Field2 = format_header(Field),
parse_header(Req#http_req{headers=[{Field2, Value}|Req#http_req.headers]},
State);
%% The Host header is required in HTTP/1.1.
header(http_eoh, #http_req{version={1, 1}, host=undefined}, State) ->
error_terminate(400, State);
%% It is however optional in HTTP/1.0.
header(http_eoh, Req=#http_req{version={1, 0}, transport=Transport,
host=undefined}, State=#state{buffer=Buffer}) ->
Port = default_port(Transport:name()),
dispatch(fun handler_init/2, Req#http_req{host=[], raw_host= <<>>,
port=Port, buffer=Buffer}, State#state{buffer= <<>>});
header(http_eoh, Req, State=#state{buffer=Buffer}) ->
handler_init(Req#http_req{buffer=Buffer}, State#state{buffer= <<>>});
header({http_error, _Bin}, _Req, State) ->
error_terminate(500, State).
-spec dispatch(fun((#http_req{}, #state{}) -> ok),
#http_req{}, #state{}) -> ok | none().
dispatch(Next, Req=#http_req{host=Host, path=Path},
State=#state{dispatch=Dispatch}) ->
%% @todo We probably want to filter the Host and Path here to allow
%% things like url rewriting.
case cowboy_dispatcher:match(Host, Path, Dispatch) of
{ok, Handler, Opts, Binds, HostInfo, PathInfo} ->
Next(Req#http_req{host_info=HostInfo, path_info=PathInfo,
bindings=Binds}, State#state{handler={Handler, Opts}});
{error, notfound, host} ->
error_terminate(400, State);
{error, notfound, path} ->
error_terminate(404, State)
end.
-spec handler_init(#http_req{}, #state{}) -> ok | none().
handler_init(Req, State=#state{listener=ListenerPid,
transport=Transport, handler={Handler, Opts}}) ->
try Handler:init({Transport:name(), http}, Req, Opts) of
{ok, Req2, HandlerState} ->
handler_handle(HandlerState, Req2, State);
{loop, Req2, HandlerState} ->
handler_before_loop(HandlerState, Req2, State);
{loop, Req2, HandlerState, hibernate} ->
handler_before_loop(HandlerState, Req2,
State#state{hibernate=true});
{loop, Req2, HandlerState, Timeout} ->
handler_before_loop(HandlerState, Req2,
State#state{loop_timeout=Timeout});
{loop, Req2, HandlerState, Timeout, hibernate} ->
handler_before_loop(HandlerState, Req2,
State#state{hibernate=true, loop_timeout=Timeout});
{shutdown, Req2, HandlerState} ->
handler_terminate(HandlerState, Req2, State);
%% @todo {upgrade, transport, Module}
{upgrade, protocol, Module} ->
Module:upgrade(ListenerPid, Handler, Opts, Req)
catch Class:Reason ->
error_terminate(500, State),
error_logger:error_msg(
"** Handler ~p terminating in init/3~n"
" for the reason ~p:~p~n"
"** Options were ~p~n"
"** Request was ~p~n** Stacktrace: ~p~n~n",
[Handler, Class, Reason, Opts, Req, erlang:get_stacktrace()])
end.
-spec handler_handle(any(), #http_req{}, #state{}) -> ok | none().
handler_handle(HandlerState, Req, State=#state{handler={Handler, Opts}}) ->
try Handler:handle(Req, HandlerState) of
{ok, Req2, HandlerState2} ->
next_request(HandlerState2, Req2, State)
catch Class:Reason ->
error_logger:error_msg(
"** Handler ~p terminating in handle/2~n"
" for the reason ~p:~p~n"
"** Options were ~p~n** Handler state was ~p~n"
"** Request was ~p~n** Stacktrace: ~p~n~n",
[Handler, Class, Reason, Opts,
HandlerState, Req, erlang:get_stacktrace()]),
handler_terminate(HandlerState, Req, State),
terminate(State)
end.
%% We don't listen for Transport closes because that would force us
%% to receive data and buffer it indefinitely.
-spec handler_before_loop(any(), #http_req{}, #state{}) -> ok | none().
handler_before_loop(HandlerState, Req, State=#state{hibernate=true}) ->
State2 = handler_loop_timeout(State),
erlang:hibernate(?MODULE, handler_loop,
[HandlerState, Req, State2#state{hibernate=false}]);
handler_before_loop(HandlerState, Req, State) ->
State2 = handler_loop_timeout(State),
handler_loop(HandlerState, Req, State2).
%% Almost the same code can be found in cowboy_http_websocket.
-spec handler_loop_timeout(#state{}) -> #state{}.
handler_loop_timeout(State=#state{loop_timeout=infinity}) ->
State#state{loop_timeout_ref=undefined};
handler_loop_timeout(State=#state{loop_timeout=Timeout,
loop_timeout_ref=PrevRef}) ->
_ = case PrevRef of undefined -> ignore; PrevRef ->
erlang:cancel_timer(PrevRef) end,
TRef = make_ref(),
erlang:send_after(Timeout, self(), {?MODULE, timeout, TRef}),
State#state{loop_timeout_ref=TRef}.
-spec handler_loop(any(), #http_req{}, #state{}) -> ok | none().
handler_loop(HandlerState, Req, State=#state{loop_timeout_ref=TRef}) ->
receive
{?MODULE, timeout, TRef} ->
next_request(HandlerState, Req, State);
{?MODULE, timeout, OlderTRef} when is_reference(OlderTRef) ->
handler_loop(HandlerState, Req, State);
Message ->
handler_call(HandlerState, Req, State, Message)
end.
-spec handler_call(any(), #http_req{}, #state{}, any()) -> ok | none().
handler_call(HandlerState, Req, State=#state{handler={Handler, Opts}},
Message) ->
try Handler:info(Message, Req, HandlerState) of
{ok, Req2, HandlerState2} ->
next_request(HandlerState2, Req2, State);
{loop, Req2, HandlerState2} ->
handler_before_loop(HandlerState2, Req2, State);
{loop, Req2, HandlerState2, hibernate} ->
handler_before_loop(HandlerState2, Req2,
State#state{hibernate=true})
catch Class:Reason ->
error_logger:error_msg(
"** Handler ~p terminating in info/3~n"
" for the reason ~p:~p~n"
"** Options were ~p~n** Handler state was ~p~n"
"** Request was ~p~n** Stacktrace: ~p~n~n",
[Handler, Class, Reason, Opts,
HandlerState, Req, erlang:get_stacktrace()])
end.
-spec handler_terminate(any(), #http_req{}, #state{}) -> ok.
handler_terminate(HandlerState, Req, #state{handler={Handler, Opts}}) ->
try
Handler:terminate(Req#http_req{resp_state=locked}, HandlerState)
catch Class:Reason ->
error_logger:error_msg(
"** Handler ~p terminating in terminate/2~n"
" for the reason ~p:~p~n"
"** Options were ~p~n** Handler state was ~p~n"
"** Request was ~p~n** Stacktrace: ~p~n~n",
[Handler, Class, Reason, Opts,
HandlerState, Req, erlang:get_stacktrace()])
end.
-spec next_request(any(), #http_req{}, #state{}) -> ok | none().
next_request(HandlerState, Req=#http_req{connection=Conn, buffer=Buffer},
State) ->
HandlerRes = handler_terminate(HandlerState, Req, State),
BodyRes = ensure_body_processed(Req),
RespRes = ensure_response(Req),
case {HandlerRes, BodyRes, RespRes, Conn} of
{ok, ok, ok, keepalive} ->
?MODULE:parse_request(State#state{
buffer=Buffer, req_empty_lines=0});
_Closed ->
terminate(State)
end.
-spec ensure_body_processed(#http_req{}) -> ok | close.
ensure_body_processed(#http_req{body_state=done}) ->
ok;
ensure_body_processed(Req=#http_req{body_state=waiting}) ->
case cowboy_http_req:body(Req) of
{error, badarg} -> ok; %% No body.
{error, _Reason} -> close;
_Any -> ok
end.
-spec ensure_response(#http_req{}) -> ok.
%% The handler has already fully replied to the client.
ensure_response(#http_req{resp_state=done}) ->
ok;
%% No response has been sent but everything apparently went fine.
%% Reply with 204 No Content to indicate this.
ensure_response(Req=#http_req{resp_state=waiting}) ->
_ = cowboy_http_req:reply(204, [], [], Req),
ok;
%% Close the chunked reply.
ensure_response(#http_req{method='HEAD', resp_state=chunks}) ->
close;
ensure_response(#http_req{socket=Socket, transport=Transport,
resp_state=chunks}) ->
Transport:send(Socket, <<"0\r\n\r\n">>),
close.
-spec error_terminate(http_status(), #state{}) -> ok.
error_terminate(Code, State=#state{socket=Socket, transport=Transport}) ->
_ = cowboy_http_req:reply(Code, [], [], #http_req{
socket=Socket, transport=Transport,
connection=close, resp_state=waiting}),
terminate(State).
-spec terminate(#state{}) -> ok.
terminate(#state{socket=Socket, transport=Transport}) ->
Transport:close(Socket),
ok.
%% Internal.
-spec version_to_connection(http_version()) -> keepalive | close.
version_to_connection({1, 1}) -> keepalive;
version_to_connection(_Any) -> close.
-spec default_port(atom()) -> 80 | 443.
default_port(ssl) -> 443;
default_port(_) -> 80.
%% @todo While 32 should be enough for everybody, we should probably make
%% this configurable or something.
-spec format_header(atom()) -> atom(); (binary()) -> binary().
format_header(Field) when is_atom(Field) ->
Field;
format_header(Field) when byte_size(Field) =< 20; byte_size(Field) > 32 ->
Field;
format_header(Field) ->
format_header(Field, true, <<>>).
-spec format_header(binary(), boolean(), binary()) -> binary().
format_header(<<>>, _Any, Acc) ->
Acc;
%% Replicate a bug in OTP for compatibility reasons when there's a - right
%% after another. Proper use should always be 'true' instead of 'not Bool'.
format_header(<< $-, Rest/bits >>, Bool, Acc) ->
format_header(Rest, not Bool, << Acc/binary, $- >>);
format_header(<< C, Rest/bits >>, true, Acc) ->
format_header(Rest, false, << Acc/binary, (cowboy_bstr:char_to_upper(C)) >>);
format_header(<< C, Rest/bits >>, false, Acc) ->
format_header(Rest, false, << Acc/binary, (cowboy_bstr:char_to_lower(C)) >>).
%% Tests.
-ifdef(TEST).
format_header_test_() ->
%% {Header, Result}
Tests = [
{<<"Sec-Websocket-Version">>, <<"Sec-Websocket-Version">>},
{<<"Sec-WebSocket-Version">>, <<"Sec-Websocket-Version">>},
{<<"sec-websocket-version">>, <<"Sec-Websocket-Version">>},
{<<"SEC-WEBSOCKET-VERSION">>, <<"Sec-Websocket-Version">>},
%% These last tests ensures we're formatting headers exactly like OTP.
%% Even though it's dumb, it's better for compatibility reasons.
{<<"Sec-WebSocket--Version">>, <<"Sec-Websocket--version">>},
{<<"Sec-WebSocket---Version">>, <<"Sec-Websocket---Version">>}
],
[{H, fun() -> R = format_header(H) end} || {H, R} <- Tests].
-endif.
