fix(authz-http): fix https://github.com/emqx/emqx/pull/8377#discussion_r911743360

apps/emqx_authz/src/emqx_authz_http.erl

@@ -85,11 +85,7 @@ authorize(
         {ok, 204, _Headers} ->
             {matched, allow};
         {ok, 200, Headers, Body} ->
-            ContentType = proplists:get_value(
+            ContentType = content_type(Headers),
-                <<"content-type">>,
-                Headers,
-                <<"application/json">>
-            ),
             case emqx_authz_utils:parse_http_resp_body(ContentType, Body) of
                 error ->
                     ?SLOG(error, #{
@@ -222,6 +218,15 @@ serialize_body(<<"application/json">>, Body) ->
 serialize_body(<<"application/x-www-form-urlencoded">>, Body) ->
     query_string(Body).
 
+content_type(Headers) when is_list(Headers) ->
+    content_type(maps:from_list(Headers));
+content_type(#{<<"content-type">> := Type}) ->
+    Type;
+content_type(#{<<"Content-Type">> := Type}) ->
+    Type;
+content_type(Headers) when is_map(Headers) ->
+    <<"application/json">>.
+
 client_vars(Client, PubSub, Topic) ->
     Client#{
         action => PubSub,

apps/emqx_authz/src/emqx_authz_utils.erl

@@ -133,13 +133,13 @@ render_sql_params(ParamList, Values) ->
     ).
 
 -spec parse_http_resp_body(binary(), binary()) -> allow | deny | ignore | error.
-parse_http_resp_body(<<"application/x-www-form-urlencoded">>, Body) ->
+parse_http_resp_body(<<"application/x-www-form-urlencoded", _/binary>>, Body) ->
     try
         result(maps:from_list(cow_qs:parse_qs(Body)))
     catch
         _:_ -> error
     end;
-parse_http_resp_body(<<"application/json">>, Body) ->
+parse_http_resp_body(<<"application/json", _/binary>>, Body) ->
     try
         result(emqx_json:decode(Body, [return_maps]))
     catch