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
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
|
%% Copyright (c) 2024, jdamanalo <[email protected]>
%% Copyright (c) 2024, 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_decompress_h).
-behavior(cowboy_stream).
-export([init/3]).
-export([data/4]).
-export([info/3]).
-export([terminate/3]).
-export([early_error/5]).
-record(state, {
next :: any(),
enabled = true :: boolean(),
ratio_limit :: non_neg_integer() | undefined,
compress = undefined :: undefined | gzip,
inflate = undefined :: undefined | zlib:zstream(),
is_reading = false :: boolean(),
%% We use a list of binaries to avoid doing unnecessary
%% memory allocations when inflating. We convert to binary
%% when we propagate the data. The data must be reversed
%% before converting to binary or inflating: this is done
%% via the buffer_to_binary/buffer_to_iovec functions.
read_body_buffer = [] :: [binary()],
read_body_is_fin = nofin :: nofin | {fin, non_neg_integer()}
}).
-spec init(cowboy_stream:streamid(), cowboy_req:req(), cowboy:opts())
-> {cowboy_stream:commands(), #state{}}.
init(StreamID, Req0, Opts) ->
Enabled = maps:get(decompress_enabled, Opts, true),
RatioLimit = maps:get(decompress_ratio_limit, Opts, 20),
{Req, State} = check_and_update_req(Req0),
Inflate = case State#state.compress of
undefined ->
undefined;
gzip ->
Z = zlib:open(),
zlib:inflateInit(Z, 31),
Z
end,
{Commands, Next} = cowboy_stream:init(StreamID, Req, Opts),
fold(Commands, State#state{next=Next, enabled=Enabled,
ratio_limit=RatioLimit, inflate=Inflate}).
-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{next=Next0, inflate=undefined}) ->
{Commands, Next} = cowboy_stream:data(StreamID, IsFin, Data, Next0),
fold(Commands, State#state{next=Next, read_body_is_fin=IsFin});
data(StreamID, IsFin, Data, State=#state{next=Next0, enabled=false, read_body_buffer=Buffer}) ->
{Commands, Next} = cowboy_stream:data(StreamID, IsFin,
buffer_to_binary([Data|Buffer]), Next0),
fold(Commands, State#state{next=Next, read_body_is_fin=IsFin});
data(StreamID, IsFin, Data, State0=#state{next=Next0, ratio_limit=RatioLimit,
inflate=Z, is_reading=true, read_body_buffer=Buffer}) ->
case inflate(Z, RatioLimit, buffer_to_iovec([Data|Buffer])) of
{error, ErrorType} ->
zlib:close(Z),
Status = case ErrorType of
data_error -> 400;
size_error -> 413
end,
Commands = [
{error_response, Status, #{<<"content-length">> => <<"0">>}, <<>>},
stop
],
fold(Commands, State0#state{inflate=undefined, read_body_buffer=[]});
{ok, Inflated} ->
State = case IsFin of
nofin ->
State0;
fin ->
zlib:close(Z),
State0#state{inflate=undefined}
end,
{Commands, Next} = cowboy_stream:data(StreamID, IsFin, Inflated, Next0),
fold(Commands, State#state{next=Next, read_body_buffer=[],
read_body_is_fin=IsFin})
end;
data(_, IsFin, Data, State=#state{read_body_buffer=Buffer}) ->
{[], State#state{read_body_buffer=[Data|Buffer], read_body_is_fin=IsFin}}.
-spec info(cowboy_stream:streamid(), any(), State)
-> {cowboy_stream:commands(), State} when State::#state{}.
info(StreamID, Info, State=#state{next=Next0, inflate=undefined}) ->
{Commands, Next} = cowboy_stream:info(StreamID, Info, Next0),
fold(Commands, State#state{next=Next});
info(StreamID, Info={CommandTag, _, _, _, _}, State=#state{next=Next0, read_body_is_fin=IsFin})
when CommandTag =:= read_body; CommandTag =:= read_body_timeout ->
{Commands0, Next1} = cowboy_stream:info(StreamID, Info, Next0),
{Commands, Next} = data(StreamID, IsFin, <<>>, State#state{next=Next1, is_reading=true}),
fold(Commands ++ Commands0, Next);
info(StreamID, Info={set_options, Opts}, State0=#state{next=Next0,
enabled=Enabled0, ratio_limit=RatioLimit0, is_reading=IsReading}) ->
Enabled = maps:get(decompress_enabled, Opts, Enabled0),
RatioLimit = maps:get(decompress_ratio_limit, Opts, RatioLimit0),
{Commands, Next} = cowboy_stream:info(StreamID, Info, Next0),
%% We can't change the enabled setting after we start reading,
%% otherwise the data becomes garbage. Changing the setting
%% is not treated as an error, it is just ignored.
State = case IsReading of
true -> State0;
false -> State0#state{enabled=Enabled}
end,
fold(Commands, State#state{next=Next, ratio_limit=RatioLimit});
info(StreamID, Info, State=#state{next=Next0}) ->
{Commands, Next} = cowboy_stream:info(StreamID, Info, Next0),
fold(Commands, State#state{next=Next}).
-spec terminate(cowboy_stream:streamid(), cowboy_stream:reason(), #state{}) -> any().
terminate(StreamID, Reason, #state{next=Next, inflate=Z}) ->
case Z of
undefined -> ok;
_ -> zlib:close(Z)
end,
cowboy_stream:terminate(StreamID, Reason, Next).
-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).
%% Internal.
%% Check whether the request needs content decoding, and if it does
%% whether it fits our criteria for decoding. We also update the
%% Req to indicate whether content was decoded.
%%
%% We always set the content_decoded value in the Req because it
%% indicates whether content decoding was attempted.
%%
%% A malformed content-encoding header results in no decoding.
check_and_update_req(Req=#{headers := Headers}) ->
ContentDecoded = maps:get(content_decoded, Req, []),
try cowboy_req:parse_header(<<"content-encoding">>, Req) of
%% We only automatically decompress when gzip is the only
%% encoding used. Since it's the only encoding used, we
%% can remove the header entirely before passing the Req
%% forward.
[<<"gzip">>] ->
{Req#{
headers => maps:remove(<<"content-encoding">>, Headers),
content_decoded => [<<"gzip">>|ContentDecoded]
}, #state{compress=gzip}};
_ ->
{Req#{content_decoded => ContentDecoded},
#state{compress=undefined}}
catch _:_ ->
{Req#{content_decoded => ContentDecoded},
#state{compress=undefined}}
end.
buffer_to_iovec(Buffer) ->
lists:reverse(Buffer).
buffer_to_binary(Buffer) ->
iolist_to_binary(lists:reverse(Buffer)).
fold(Commands, State) ->
fold(Commands, State, []).
fold([], State, Acc) ->
{lists:reverse(Acc), State};
fold([{response, Status, Headers0, Body}|Tail], State=#state{enabled=true}, Acc) ->
Headers = add_accept_encoding(Headers0),
fold(Tail, State, [{response, Status, Headers, Body}|Acc]);
fold([{headers, Status, Headers0} | Tail], State=#state{enabled=true}, Acc) ->
Headers = add_accept_encoding(Headers0),
fold(Tail, State, [{headers, Status, Headers}|Acc]);
fold([Command|Tail], State, Acc) ->
fold(Tail, State, [Command|Acc]).
add_accept_encoding(Headers=#{<<"accept-encoding">> := AcceptEncoding}) ->
try cow_http_hd:parse_accept_encoding(iolist_to_binary(AcceptEncoding)) of
List ->
case lists:keyfind(<<"gzip">>, 1, List) of
%% gzip is excluded but this handler is enabled; we replace.
{_, 0} ->
Replaced = lists:keyreplace(<<"gzip">>, 1, List, {<<"gzip">>, 1000}),
Codings = build_accept_encoding(Replaced),
Headers#{<<"accept-encoding">> => Codings};
{_, _} ->
Headers;
false ->
case lists:keyfind(<<"*">>, 1, List) of
%% Others are excluded along with gzip; we add.
{_, 0} ->
WithGzip = [{<<"gzip">>, 1000} | List],
Codings = build_accept_encoding(WithGzip),
Headers#{<<"accept-encoding">> => Codings};
{_, _} ->
Headers;
false ->
Headers#{<<"accept-encoding">> => [AcceptEncoding, <<", gzip">>]}
end
end
catch _:_ ->
%% The accept-encoding header is invalid. Probably empty. We replace it with ours.
Headers#{<<"accept-encoding">> => <<"gzip">>}
end;
add_accept_encoding(Headers) ->
Headers#{<<"accept-encoding">> => <<"gzip">>}.
%% @todo From cowlib, maybe expose?
qvalue_to_iodata(0) -> <<"0">>;
qvalue_to_iodata(Q) when Q < 10 -> [<<"0.00">>, integer_to_binary(Q)];
qvalue_to_iodata(Q) when Q < 100 -> [<<"0.0">>, integer_to_binary(Q)];
qvalue_to_iodata(Q) when Q < 1000 -> [<<"0.">>, integer_to_binary(Q)];
qvalue_to_iodata(1000) -> <<"1">>.
%% @todo Should be added to Cowlib.
build_accept_encoding([{ContentCoding, Q}|Tail]) ->
Weight = iolist_to_binary(qvalue_to_iodata(Q)),
Acc = <<ContentCoding/binary, ";q=", Weight/binary>>,
do_build_accept_encoding(Tail, Acc).
do_build_accept_encoding([{ContentCoding, Q}|Tail], Acc0) ->
Weight = iolist_to_binary(qvalue_to_iodata(Q)),
Acc = <<Acc0/binary, ", ", ContentCoding/binary, ";q=", Weight/binary>>,
do_build_accept_encoding(Tail, Acc);
do_build_accept_encoding([], Acc) ->
Acc.
inflate(Z, RatioLimit, Data) ->
try
{Status, Output} = zlib:safeInflate(Z, Data),
Size = iolist_size(Output),
do_inflate(Z, Size, iolist_size(Data) * RatioLimit, Status, [Output])
catch
error:data_error ->
{error, data_error}
end.
do_inflate(_, Size, Limit, _, _) when Size > Limit ->
{error, size_error};
do_inflate(Z, Size0, Limit, continue, Acc) ->
{Status, Output} = zlib:safeInflate(Z, []),
Size = Size0 + iolist_size(Output),
do_inflate(Z, Size, Limit, Status, [Output | Acc]);
do_inflate(_, _, _, finished, Acc) ->
{ok, iolist_to_binary(lists:reverse(Acc))}.
|
