1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
|
%% Copyright (c) 2016-2017, Loïc Hoguin <[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.
-module(cowboy_stream_h).
-behavior(cowboy_stream).
-export([init/3]).
-export([data/4]).
-export([info/3]).
-export([terminate/3]).
-export([early_error/5]).
-export([request_process/3]).
-export([execute/3]).
-export([resume/5]).
%% @todo Need to call subsequent handlers.
-record(state, {
ref = undefined :: ranch:ref(),
pid = undefined :: pid(),
read_body_ref = undefined :: reference() | undefined,
read_body_timer_ref = undefined :: reference() | undefined,
read_body_length = 0 :: non_neg_integer() | infinity,
read_body_is_fin = nofin :: nofin | {fin, non_neg_integer()},
read_body_buffer = <<>> :: binary(),
body_length = 0 :: non_neg_integer()
}).
%% @todo For shutting down children we need to have a timeout before we terminate
%% the stream like supervisors do. So here just send a message to yourself first,
%% and then decide what to do when receiving this message.
-spec init(cowboy_stream:streamid(), cowboy_req:req(), cowboy:opts())
-> {[{spawn, pid(), timeout()}], #state{}}.
init(_StreamID, Req=#{ref := Ref}, Opts) ->
Env = maps:get(env, Opts, #{}),
Middlewares = maps:get(middlewares, Opts, [cowboy_router, cowboy_handler]),
Shutdown = maps:get(shutdown_timeout, Opts, 5000),
Pid = proc_lib:spawn_link(?MODULE, request_process, [Req, Env, Middlewares]),
{[{spawn, Pid, Shutdown}], #state{ref=Ref, pid=Pid}}.
%% If we receive data and stream is waiting for data:
%% If we accumulated enough data or IsFin=fin, send it.
%% If not, buffer it.
%% If not, buffer it.
-spec data(cowboy_stream:streamid(), cowboy_stream:fin(), cowboy_req:resp_body(), State)
-> {cowboy_stream:commands(), State} when State::#state{}.
data(_StreamID, IsFin, Data, State=#state{
read_body_ref=undefined, read_body_buffer=Buffer, body_length=BodyLen}) ->
{[], State#state{
read_body_is_fin=IsFin,
read_body_buffer= << Buffer/binary, Data/binary >>,
body_length=BodyLen + byte_size(Data)}};
data(_StreamID, nofin, Data, State=#state{
read_body_length=ReadLen, read_body_buffer=Buffer, body_length=BodyLen})
when byte_size(Data) + byte_size(Buffer) < ReadLen ->
{[], State#state{
read_body_buffer= << Buffer/binary, Data/binary >>,
body_length=BodyLen + byte_size(Data)}};
data(_StreamID, IsFin, Data, State=#state{pid=Pid, read_body_ref=Ref,
read_body_timer_ref=TRef, read_body_buffer=Buffer, body_length=BodyLen0}) ->
BodyLen = BodyLen0 + byte_size(Data),
ok = erlang:cancel_timer(TRef, [{async, true}, {info, false}]),
send_request_body(Pid, Ref, IsFin, BodyLen, <<Buffer/binary, Data/binary>>),
{[], State#state{
read_body_ref=undefined,
read_body_timer_ref=undefined,
read_body_buffer= <<>>,
body_length=BodyLen}}.
-spec info(cowboy_stream:streamid(), any(), State)
-> {cowboy_stream:commands(), State} when State::#state{}.
info(_StreamID, {'EXIT', Pid, normal}, State=#state{pid=Pid}) ->
{[stop], State};
info(_StreamID, {'EXIT', Pid, {{request_error, Reason, _HumanReadable}, _}}, State=#state{pid=Pid}) ->
%% @todo Optionally report the crash to help debugging.
%%report_crash(Ref, StreamID, Pid, Reason, Stacktrace),
Status = case Reason of
timeout -> 408;
payload_too_large -> 413;
_ -> 400
end,
%% @todo Headers? Details in body? More stuff in debug only?
{[{error_response, Status, #{<<"content-length">> => <<"0">>}, <<>>}, stop], State};
info(StreamID, Exit = {'EXIT', Pid, {Reason, Stacktrace}}, State=#state{ref=Ref, pid=Pid}) ->
report_crash(Ref, StreamID, Pid, Reason, Stacktrace),
{[
{error_response, 500, #{<<"content-length">> => <<"0">>}, <<>>},
{internal_error, Exit, 'Stream process crashed.'}
], State};
%% Request body, body buffered large enough or complete.
info(_StreamID, {read_body, Ref, Length, _}, State=#state{pid=Pid,
read_body_is_fin=IsFin, read_body_buffer=Buffer, body_length=BodyLen})
when IsFin =:= fin; byte_size(Buffer) >= Length ->
send_request_body(Pid, Ref, IsFin, BodyLen, Buffer),
{[], State#state{read_body_buffer= <<>>}};
%% Request body, not enough to send yet.
info(StreamID, {read_body, Ref, Length, Period}, State) ->
TRef = erlang:send_after(Period, self(), {{self(), StreamID}, {read_body_timeout, Ref}}),
{[{flow, Length}], State#state{read_body_ref=Ref, read_body_timer_ref=TRef, read_body_length=Length}};
%% Request body reading timeout; send what we got.
info(_StreamID, {read_body_timeout, Ref}, State=#state{pid=Pid, read_body_ref=Ref,
read_body_is_fin=IsFin, read_body_buffer=Buffer, body_length=BodyLen}) ->
send_request_body(Pid, Ref, IsFin, BodyLen, Buffer),
{[], State#state{read_body_ref=undefined, read_body_timer_ref=undefined, read_body_buffer= <<>>}};
info(_StreamID, {read_body_timeout, _}, State) ->
{[], State};
%% Response.
info(_StreamID, Inform = {inform, _, _}, State) ->
{[Inform], State};
info(_StreamID, Response = {response, _, _, _}, State) ->
{[Response], State};
info(_StreamID, Headers = {headers, _, _}, State) ->
{[Headers], State};
info(_StreamID, Data = {data, _, _}, State) ->
{[Data], State};
info(_StreamID, Push = {push, _, _, _, _, _, _, _}, State) ->
{[Push], State};
info(_StreamID, SwitchProtocol = {switch_protocol, _, _, _}, State) ->
{[SwitchProtocol], State};
%% Stray message.
info(_StreamID, _Info, State) ->
{[], State}.
-spec terminate(cowboy_stream:streamid(), cowboy_stream:reason(), #state{}) -> ok.
terminate(_StreamID, _Reason, _State) ->
ok.
-spec early_error(cowboy_stream:streamid(), cowboy_stream:reason(),
cowboy_stream:partial_req(), Resp, cowboy:opts()) -> Resp
when Resp::cowboy_stream:resp_command().
early_error(StreamID, Reason, PartialReq, Resp, Opts) ->
cowboy_stream:early_error(StreamID, Reason, PartialReq, Resp, Opts).
send_request_body(Pid, Ref, nofin, _, Data) ->
Pid ! {request_body, Ref, nofin, Data},
ok;
send_request_body(Pid, Ref, fin, BodyLen, Data) ->
Pid ! {request_body, Ref, fin, BodyLen, Data},
ok.
%% We use ~999999p here instead of ~w because the latter doesn't
%% support printable strings.
report_crash(_, _, _, normal, _) ->
ok;
report_crash(_, _, _, shutdown, _) ->
ok;
report_crash(_, _, _, {shutdown, _}, _) ->
ok;
report_crash(Ref, StreamID, Pid, Reason, Stacktrace) ->
error_logger:error_msg(
"Ranch listener ~p, connection process ~p, stream ~p "
"had its request process ~p exit with reason "
"~999999p and stacktrace ~999999p~n",
[Ref, self(), StreamID, Pid, Reason, Stacktrace]).
%% Request process.
%% We catch all exceptions in order to add the stacktrace to
%% the exit reason as it is not propagated by proc_lib otherwise
%% and therefore not present in the 'EXIT' message. We want
%% the stacktrace in order to simplify debugging of errors.
%%
%% This + the behavior in proc_lib means that we will get a
%% {Reason, Stacktrace} tuple for every exceptions, instead of
%% just for errors and throws.
%%
%% @todo Better spec.
-spec request_process(_, _, _) -> _.
request_process(Req, Env, Middlewares) ->
OTP = erlang:system_info(otp_release),
try
execute(Req, Env, Middlewares)
catch
exit:Reason ->
Stacktrace = erlang:get_stacktrace(),
erlang:raise(exit, {Reason, Stacktrace}, Stacktrace);
%% OTP 19 does not propagate any exception stacktraces,
%% we therefore add it for every class of exception.
_:Reason when OTP =:= "19" ->
Stacktrace = erlang:get_stacktrace(),
erlang:raise(exit, {Reason, Stacktrace}, Stacktrace);
Class:Reason ->
erlang:raise(Class, Reason, erlang:get_stacktrace())
end.
%% @todo
%-spec execute(cowboy_req:req(), #state{}, cowboy_middleware:env(), [module()])
% -> ok.
-spec execute(_, _, _) -> _.
execute(_, _, []) ->
ok; %% @todo Maybe error reason should differ here and there.
execute(Req, Env, [Middleware|Tail]) ->
case Middleware:execute(Req, Env) of
{ok, Req2, Env2} ->
execute(Req2, Env2, Tail);
{suspend, Module, Function, Args} ->
proc_lib:hibernate(?MODULE, resume, [Env, Tail, Module, Function, Args]);
{stop, _Req2} ->
ok %% @todo Maybe error reason should differ here and there.
end.
-spec resume(cowboy_middleware:env(), [module()],
module(), module(), [any()]) -> ok.
resume(Env, Tail, Module, Function, Args) ->
case apply(Module, Function, Args) of
{ok, Req2, Env2} ->
execute(Req2, Env2, Tail);
{suspend, Module2, Function2, Args2} ->
proc_lib:hibernate(?MODULE, resume, [Env, Tail, Module2, Function2, Args2]);
{stop, _Req2} ->
ok %% @todo Maybe error reason should differ here and there.
end.
|
