%% Copyright (c) 2011-2012, 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>
%% <dt>urldecode</dt><dd>Function and options argument to use when decoding
%% URL encoded strings. Defaults to `{fun cowboy_http:urldecode/2, crash}'.
%% </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_protocol).
%% API.
-export([start_link/4]).
%% Internal.
-export([init/4]).
-export([parse_request/1]).
-export([handler_loop/3]).
-type onrequest_fun() :: fun((Req) -> Req).
-type onresponse_fun() ::
fun((cowboy_http:status(), cowboy_http:headers(), Req) -> Req).
-export_type([onrequest_fun/0]).
-export_type([onresponse_fun/0]).
-record(state, {
listener :: pid(),
socket :: inet:socket(),
transport :: module(),
dispatch :: cowboy_dispatcher:dispatch_rules(),
handler :: {module(), any()},
onrequest :: undefined | onrequest_fun(),
onresponse = undefined :: undefined | onresponse_fun(),
urldecode :: {fun((binary(), T) -> binary()), T},
req_empty_lines = 0 :: integer(),
max_empty_lines :: integer(),
req_keepalive = 1 :: integer(),
max_keepalive :: integer(),
max_request_line_length :: integer(),
max_header_name_length :: integer(),
max_header_value_length :: integer(),
timeout :: timeout(),
buffer = <<>> :: binary(),
host_tokens = undefined :: undefined | cowboy_dispatcher:tokens(),
path_tokens = undefined :: undefined | '*' | cowboy_dispatcher:tokens(),
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}.
%% Internal.
%% @doc Faster alternative to proplists:get_value/3.
%% @private
get_value(Key, Opts, Default) ->
case lists:keyfind(Key, 1, Opts) of
{_, Value} -> Value;
_ -> Default
end.
%% @private
-spec init(pid(), inet:socket(), module(), any()) -> ok.
init(ListenerPid, Socket, Transport, Opts) ->
Dispatch = get_value(dispatch, Opts, []),
MaxEmptyLines = get_value(max_empty_lines, Opts, 5),
MaxKeepalive = get_value(max_keepalive, Opts, infinity),
MaxRequestLineLength = get_value(max_request_line_length, Opts, 4096),
MaxHeaderNameLength = get_value(max_header_name_length, Opts, 64),
MaxHeaderValueLength = get_value(max_header_value_length, Opts, 4096),
OnRequest = get_value(onrequest, Opts, undefined),
OnResponse = get_value(onresponse, Opts, undefined),
Timeout = get_value(timeout, Opts, 5000),
URLDecDefault = {fun cowboy_http:urldecode/2, crash},
URLDec = get_value(urldecode, Opts, URLDecDefault),
ok = ranch:accept_ack(ListenerPid),
wait_request(#state{listener=ListenerPid, socket=Socket,
transport=Transport, dispatch=Dispatch,
max_empty_lines=MaxEmptyLines, max_keepalive=MaxKeepalive,
max_request_line_length=MaxRequestLineLength,
max_header_name_length=MaxHeaderNameLength,
max_header_value_length=MaxHeaderValueLength,
timeout=Timeout, onrequest=OnRequest, onresponse=OnResponse,
urldecode=URLDec}).
-spec wait_request(#state{}) -> ok.
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.
%% @private
-spec parse_request(#state{}) -> ok.
%% 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_request_line_length=MaxLength,
req_empty_lines=ReqEmpty, max_empty_lines=MaxEmpty}) ->
case binary:split(Buffer, <<"\r\n">>) of
[_] when byte_size(Buffer) > MaxLength ->
error_terminate(413, State);
[<< "\n", _/binary >>] ->
error_terminate(400, State);
[_] ->
wait_request(State);
[<<>>, _] when ReqEmpty =:= MaxEmpty ->
error_terminate(400, State);
[<<>>, Rest] ->
parse_request(State#state{
buffer=Rest, req_empty_lines=ReqEmpty + 1});
[RequestLine, Rest] ->
case cowboy_http:request_line(RequestLine) of
{Method, AbsPath, Version} ->
request(State#state{buffer=Rest}, Method, AbsPath, Version);
{error, _} ->
error_terminate(400, State)
end
end.
-spec request(#state{}, binary(), binary(), cowboy_http:version()) -> ok.
request(State, _, _, Version)
when Version =/= {1, 0}, Version =/= {1, 1} ->
error_terminate(505, State);
request(State=#state{socket=Socket, transport=Transport,
onresponse=OnResponse, urldecode=URLDec},
Method, <<"*">>, Version) ->
Connection = version_to_connection(State, Version),
parse_header(State#state{path_tokens= '*'},
cowboy_req:new(Socket, Transport, Connection, Method, Version,
<<"*">>, <<>>, OnResponse, URLDec));
request(State=#state{socket=Socket, transport=Transport,
onresponse=OnResponse, urldecode=URLDec={URLDecFun, URLDecArg}},
Method, AbsPath, Version) ->
Connection = version_to_connection(State, Version),
{PathTokens, Path, Qs} = cowboy_dispatcher:split_path(AbsPath,
fun(Bin) -> URLDecFun(Bin, URLDecArg) end),
parse_header(State#state{path_tokens=PathTokens},
cowboy_req:new(Socket, Transport, Connection, Method, Version,
Path, Qs, OnResponse, URLDec)).
-spec parse_header(#state{}, cowboy_req:req()) -> ok.
parse_header(State=#state{buffer= << "\r\n", Rest/binary >>}, Req) ->
header_end(State#state{buffer=Rest}, Req);
parse_header(State=#state{buffer=Buffer,
max_header_name_length=MaxLength}, Req) ->
case binary:split(Buffer, <<":">>) of
[_] when byte_size(Buffer) > MaxLength ->
error_terminate(413, State);
[_] ->
wait_header(State, Req, fun parse_header/2);
[Name, Rest] ->
Name2 = cowboy_bstr:to_lower(Name),
Rest2 = cowboy_http:whitespace(Rest, fun(D) -> D end),
parse_header_value(State#state{buffer=Rest2}, Req, Name2, <<>>)
end.
parse_header_value(State=#state{buffer=Buffer,
max_header_value_length=MaxLength}, Req, Name, SoFar) ->
case binary:split(Buffer, <<"\r\n">>) of
[_] when byte_size(Buffer) + byte_size(SoFar) > MaxLength ->
error_terminate(413, State);
[_] ->
wait_header(State, Req,
fun(S, R) -> parse_header_value(S, R, Name, SoFar) end);
[Value, << C, Rest/binary >>] when C =:= $\s; C =:= $\t ->
parse_header_value(State#state{buffer=Rest}, Req, Name,
<< SoFar/binary, Value/binary >>);
[Value, Rest] ->
header(State#state{buffer=Rest}, Req, Name,
<< SoFar/binary, Value/binary >>)
end.
-spec wait_header(#state{}, cowboy_req:req(), fun()) -> ok.
wait_header(State=#state{socket=Socket, transport=Transport,
timeout=T, buffer=Buffer}, Req, Fun) ->
case Transport:recv(Socket, 0, T) of
{ok, Data} -> Fun(State#state{
buffer= << Buffer/binary, Data/binary >>}, Req);
{error, timeout} -> error_terminate(408, State);
{error, closed} -> terminate(State)
end.
-spec header(#state{}, cowboy_req:req(), binary(), binary()) -> ok.
header(State=#state{host_tokens=undefined, transport=Transport},
Req, <<"host">>, RawHost) ->
RawHost2 = cowboy_bstr:to_lower(RawHost),
case catch cowboy_dispatcher:split_host(RawHost2) of
{HostTokens, Host, undefined} ->
Port = default_port(Transport:name()),
parse_header(State#state{host_tokens=HostTokens},
cowboy_req:set_host(Host, Port, RawHost, Req));
{HostTokens, Host, Port} ->
parse_header(State#state{host_tokens=HostTokens},
cowboy_req:set_host(Host, Port, RawHost, Req));
{'EXIT', _Reason} ->
error_terminate(400, State)
end;
%% Ignore Host headers if we already have it.
header(State, Req, <<"host">>, _) ->
parse_header(State, Req);
header(State=#state{req_keepalive=Keepalive, max_keepalive=MaxKeepalive},
Req, <<"connection">>, Connection)
when Keepalive < MaxKeepalive ->
parse_header(State, cowboy_req:set_connection(Connection, Req));
header(State, Req, Name, Value) ->
parse_header(State, cowboy_req:add_header(Name, Value, Req)).
%% The Host header is required in HTTP/1.1 and optional in HTTP/1.0.
header_end(State=#state{host_tokens=undefined,
buffer=Buffer, transport=Transport}, Req) ->
case cowboy_req:version(Req) of
{{1, 1}, _} ->
error_terminate(400, State);
{{1, 0}, Req2} ->
Port = default_port(Transport:name()),
onrequest(
cowboy_req:set_buffer(Buffer,
cowboy_req:set_host(<<>>, Port, <<>>, Req2)),
State#state{buffer= <<>>, host_tokens=[]})
end;
header_end(State=#state{buffer=Buffer}, Req) ->
onrequest(cowboy_req:set_buffer(Buffer, Req), State#state{buffer= <<>>}).
%% Call the global onrequest callback. The callback can send a reply,
%% in which case we consider the request handled and move on to the next
%% one. Note that since we haven't dispatched yet, we don't know the
%% handler, host_info, path_info or bindings yet.
-spec onrequest(cowboy_req:req(), #state{}) -> ok.
onrequest(Req, State=#state{onrequest=undefined}) ->
dispatch(Req, State);
onrequest(Req, State=#state{onrequest=OnRequest}) ->
Req2 = OnRequest(Req),
case cowboy_req:get_resp_state(Req2) of
waiting -> dispatch(Req2, State);
_ -> next_request(Req2, State, ok)
end.
-spec dispatch(cowboy_req:req(), #state{}) -> ok.
dispatch(Req, State=#state{dispatch=Dispatch,
host_tokens=HostTokens, path_tokens=PathTokens}) ->
case cowboy_dispatcher:match(HostTokens, PathTokens, Dispatch) of
{ok, Handler, Opts, Bindings, HostInfo, PathInfo} ->
Req2 = cowboy_req:set_bindings(HostInfo, PathInfo, Bindings, Req),
handler_init(Req2, State#state{handler={Handler, Opts},
host_tokens=undefined, path_tokens=undefined});
{error, notfound, host} ->
error_terminate(400, State);
{error, notfound, path} ->
error_terminate(404, State)
end.
-spec handler_init(cowboy_req:req(), #state{}) -> ok.
handler_init(Req, State=#state{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} ->
upgrade_protocol(Req, State, Module)
catch Class:Reason ->
error_terminate(500, State),
PLReq = cowboy_req:to_list(Req),
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, PLReq, erlang:get_stacktrace()])
end.
-spec upgrade_protocol(cowboy_req:req(), #state{}, atom()) -> ok.
upgrade_protocol(Req, State=#state{listener=ListenerPid,
handler={Handler, Opts}}, Module) ->
case Module:upgrade(ListenerPid, Handler, Opts, Req) of
{UpgradeRes, Req2} -> next_request(Req2, State, UpgradeRes);
_Any -> terminate(State)
end.
-spec handler_handle(any(), cowboy_req:req(), #state{}) -> ok.
handler_handle(HandlerState, Req, State=#state{handler={Handler, Opts}}) ->
try Handler:handle(Req, HandlerState) of
{ok, Req2, HandlerState2} ->
terminate_request(HandlerState2, Req2, State)
catch Class:Reason ->
PLReq = cowboy_req:to_list(Req),
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, PLReq, erlang:get_stacktrace()]),
handler_terminate(HandlerState, Req, State),
error_terminate(500, 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(), cowboy_req:req(), #state{}) -> ok.
handler_before_loop(HandlerState, Req, State=#state{hibernate=true}) ->
State2 = handler_loop_timeout(State),
catch erlang:hibernate(?MODULE, handler_loop,
[HandlerState, Req, State2#state{hibernate=false}]),
ok;
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_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 = erlang:start_timer(Timeout, self(), ?MODULE),
State#state{loop_timeout_ref=TRef}.
-spec handler_loop(any(), cowboy_req:req(), #state{}) -> ok.
handler_loop(HandlerState, Req, State=#state{loop_timeout_ref=TRef}) ->
receive
{timeout, TRef, ?MODULE} ->
terminate_request(HandlerState, Req, State);
{timeout, OlderTRef, ?MODULE} when is_reference(OlderTRef) ->
handler_loop(HandlerState, Req, State);
Message ->
handler_call(HandlerState, Req, State, Message)
end.
-spec handler_call(any(), cowboy_req:req(), #state{}, any()) -> ok.
handler_call(HandlerState, Req, State=#state{handler={Handler, Opts}},
Message) ->
try Handler:info(Message, Req, HandlerState) of
{ok, Req2, HandlerState2} ->
terminate_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 ->
PLReq = cowboy_req:to_list(Req),
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, PLReq, erlang:get_stacktrace()]),
handler_terminate(HandlerState, Req, State),
error_terminate(500, State)
end.
-spec handler_terminate(any(), cowboy_req:req(), #state{}) -> ok.
handler_terminate(HandlerState, Req, #state{handler={Handler, Opts}}) ->
try
Handler:terminate(cowboy_req:lock(Req), HandlerState)
catch Class:Reason ->
PLReq = cowboy_req:to_list(Req),
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, PLReq, erlang:get_stacktrace()])
end.
-spec terminate_request(any(), cowboy_req:req(), #state{}) -> ok.
terminate_request(HandlerState, Req, State) ->
HandlerRes = handler_terminate(HandlerState, Req, State),
next_request(Req, State, HandlerRes).
-spec next_request(cowboy_req:req(), #state{}, any()) -> ok.
next_request(Req, State=#state{
req_keepalive=Keepalive}, HandlerRes) ->
cowboy_req:ensure_response(Req, 204),
{BodyRes, Buffer} = case cowboy_req:skip_body(Req) of
{ok, Req2} -> {ok, cowboy_req:get_buffer(Req2)};
{error, _} -> {close, <<>>}
end,
%% Flush the resp_sent message before moving on.
receive {cowboy_req, resp_sent} -> ok after 0 -> ok end,
case {HandlerRes, BodyRes, cowboy_req:get_connection(Req)} of
{ok, ok, keepalive} ->
?MODULE:parse_request(State#state{
buffer=Buffer, host_tokens=undefined, path_tokens=undefined,
req_empty_lines=0, req_keepalive=Keepalive + 1});
_Closed ->
terminate(State)
end.
%% Only send an error reply if there is no resp_sent message.
-spec error_terminate(cowboy_http:status(), #state{}) -> ok.
error_terminate(Code, State=#state{socket=Socket, transport=Transport,
onresponse=OnResponse}) ->
receive
{cowboy_req, resp_sent} -> ok
after 0 ->
_ = cowboy_req:reply(Code, cowboy_req:new(Socket, Transport,
close, <<"GET">>, {1, 1}, <<>>, <<>>, OnResponse, undefined)),
ok
end,
terminate(State).
-spec terminate(#state{}) -> ok.
terminate(#state{socket=Socket, transport=Transport}) ->
Transport:close(Socket),
ok.
%% Internal.
-spec version_to_connection(#state{}, cowboy_http:version())
-> keepalive | close.
version_to_connection(#state{req_keepalive=Keepalive,
max_keepalive=MaxKeepalive}, _) when Keepalive >= MaxKeepalive ->
close;
version_to_connection(_, {1, 1}) ->
keepalive;
version_to_connection(_, _) ->
close.
-spec default_port(atom()) -> 80 | 443.
default_port(ssl) -> 443;
default_port(_) -> 80.
