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authorLoïc Hoguin <[email protected]>2018-11-02 12:36:51 +0100
committerLoïc Hoguin <[email protected]>2018-11-02 13:49:54 +0100
commit399b6a16b4a571e293437dcc8f85808f83b32ff6 (patch)
tree5b1d5b0e06b1f3bf08f1a858770ff00fe3c2fe3f /src
parentd4dff2105500d960479d278981f42d42beb54175 (diff)
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Better handle content negotiation when accept contains charsets
Thanks to Philip Witty for help figuring this out.
Diffstat (limited to 'src')
-rw-r--r--src/cowboy_rest.erl89
1 files changed, 70 insertions, 19 deletions
diff --git a/src/cowboy_rest.erl b/src/cowboy_rest.erl
index 2780a90..63f3d99 100644
--- a/src/cowboy_rest.erl
+++ b/src/cowboy_rest.erl
@@ -245,7 +245,7 @@
language_a :: undefined | binary(),
%% Charset.
- charsets_p = [] :: [binary()],
+ charsets_p = undefined :: undefined | [binary()],
charset_a :: undefined | binary(),
%% Whether the resource exists.
@@ -503,16 +503,55 @@ match_media_type(Req, State, Accept,
match_media_type(Req, State, Accept, [_Any|Tail], MediaType) ->
match_media_type(Req, State, Accept, Tail, MediaType).
-match_media_type_params(Req, State, _Accept,
- [Provided = {{TP, STP, '*'}, _Fun}|_Tail],
- {{_TA, _STA, Params_A}, _QA, _APA}) ->
- PMT = {TP, STP, Params_A},
- languages_provided(Req#{media_type => PMT},
- State#state{content_type_a=Provided});
match_media_type_params(Req, State, Accept,
- [Provided = {PMT = {_TP, _STP, Params_P}, _Fun}|Tail],
+ [Provided = {{TP, STP, '*'}, _Fun}|Tail],
+ MediaType = {{TA, _STA, Params_A0}, _QA, _APA}) ->
+ case lists:keytake(<<"charset">>, 1, Params_A0) of
+ {value, {_, Charset}, Params_A} when TA =:= <<"text">> ->
+ %% When we match against a wildcard, the media type is text
+ %% and has a charset parameter, we call charsets_provided
+ %% and check that the charset is provided. If the callback
+ %% is not exported, we accept inconditionally but ignore
+ %% the given charset so as to not send a wrong value back.
+ case call(Req, State, charsets_provided) of
+ no_call ->
+ languages_provided(Req#{media_type => {TP, STP, Params_A0}},
+ State#state{content_type_a=Provided});
+ {stop, Req2, HandlerState} ->
+ terminate(Req2, State#state{handler_state=HandlerState});
+ {Switch, Req2, HandlerState} when element(1, Switch) =:= switch_handler ->
+ switch_handler(Switch, Req2, HandlerState);
+ {CP, Req2, HandlerState} ->
+ State2 = State#state{handler_state=HandlerState, charsets_p=CP},
+ case lists:member(Charset, CP) of
+ false ->
+ match_media_type(Req2, State2, Accept, Tail, MediaType);
+ true ->
+ languages_provided(Req2#{media_type => {TP, STP, Params_A}},
+ State2#state{content_type_a=Provided,
+ charset_a=Charset})
+ end
+ end;
+ _ ->
+ languages_provided(Req#{media_type => {TP, STP, Params_A0}},
+ State#state{content_type_a=Provided})
+ end;
+match_media_type_params(Req, State, Accept,
+ [Provided = {PMT = {TP, STP, Params_P0}, Fun}|Tail],
MediaType = {{_TA, _STA, Params_A}, _QA, _APA}) ->
- case lists:sort(Params_P) =:= lists:sort(Params_A) of
+ case lists:sort(Params_P0) =:= lists:sort(Params_A) of
+ true when TP =:= <<"text">> ->
+ %% When a charset was provided explicitly in both the charset header
+ %% and the media types provided and the negotiation is successful,
+ %% we keep the charset and don't call charsets_provided. This only
+ %% applies to text media types, however.
+ {Charset, Params_P} = case lists:keytake(<<"charset">>, 1, Params_P0) of
+ false -> {undefined, Params_P0};
+ {value, {_, Charset0}, Params_P1} -> {Charset0, Params_P1}
+ end,
+ languages_provided(Req#{media_type => {TP, STP, Params_P}},
+ State#state{content_type_a={{TP, STP, Params_P}, Fun},
+ charset_a=Charset});
true ->
languages_provided(Req#{media_type => PMT},
State#state{content_type_a=Provided});
@@ -587,6 +626,26 @@ set_language(Req, State=#state{language_a=Language}) ->
%% charsets_provided should return a list of binary values indicating
%% which charsets are accepted by the resource.
+%%
+%% A charset may have been selected while negotiating the accept header.
+%% There's no need to select one again.
+charsets_provided(Req, State=#state{charset_a=Charset})
+ when Charset =/= undefined ->
+ set_content_type(Req, State);
+%% If charsets_p is defined, use it instead of calling charsets_provided
+%% again. We also call this clause during normal execution to avoid
+%% duplicating code.
+charsets_provided(Req, State=#state{charsets_p=[]}) ->
+ not_acceptable(Req, State);
+charsets_provided(Req, State=#state{charsets_p=CP})
+ when CP =/= undefined ->
+ case cowboy_req:parse_header(<<"accept-charset">>, Req) of
+ undefined ->
+ set_content_type(Req, State#state{charset_a=hd(CP)});
+ AcceptCharset0 ->
+ AcceptCharset = prioritize_charsets(AcceptCharset0),
+ choose_charset(Req, State, AcceptCharset)
+ end;
charsets_provided(Req, State) ->
case call(Req, State, charsets_provided) of
no_call ->
@@ -595,17 +654,8 @@ charsets_provided(Req, State) ->
terminate(Req2, State#state{handler_state=HandlerState});
{Switch, Req2, HandlerState} when element(1, Switch) =:= switch_handler ->
switch_handler(Switch, Req2, HandlerState);
- {[], Req2, HandlerState} ->
- not_acceptable(Req2, State#state{handler_state=HandlerState});
{CP, Req2, HandlerState} ->
- State2 = State#state{handler_state=HandlerState, charsets_p=CP},
- case cowboy_req:parse_header(<<"accept-charset">>, Req2) of
- undefined ->
- set_content_type(Req2, State2#state{charset_a=hd(CP)});
- AcceptCharset ->
- AcceptCharset2 = prioritize_charsets(AcceptCharset),
- choose_charset(Req2, State2, AcceptCharset2)
- end
+ charsets_provided(Req2, State#state{handler_state=HandlerState, charsets_p=CP})
end.
%% The special value "*", if present in the Accept-Charset field,
@@ -690,6 +740,7 @@ variances(Req, State=#state{content_types_p=CTP,
[_|_] -> [<<"accept-language">>|Variances]
end,
Variances3 = case CP of
+ undefined -> Variances2;
[] -> Variances2;
[_] -> Variances2;
[_|_] -> [<<"accept-charset">>|Variances2]