-module(nova_request_plugin).
-moduledoc false.
-behaviour(nova_plugin).
-export([
pre_request/4,
post_request/4,
plugin_info/0
]).
%%--------------------------------------------------------------------
-doc "Pre-request callback".
-spec pre_request(Req :: cowboy_req:req(), Env :: any(), Options :: map(), State :: any()) ->
{ok, Req0 :: cowboy_req:req(), NewState :: any()} |
{stop, Req0 :: cowboy_req:req(), NewState :: any()}.
pre_request(Req, _Env, Options, State) ->
ListOptions = maps:to_list(Options),
modulate_state(read_request_body(Req, ListOptions), ListOptions, State).
%%--------------------------------------------------------------------
-doc "Post-request callback".
-spec post_request(Req :: cowboy_req:req(), Env :: any(), Options :: map(), State :: any()) ->
{ok, Req0 :: cowboy_req:req(), NewState :: any()}.
post_request(Req, _Env, _Options, State) ->
{ok, Req, State}.
%%--------------------------------------------------------------------
-doc "nova_plugin callback. Returns information about the plugin.".
-spec plugin_info() -> #{title := binary(),
version := binary(),
url := binary(),
authors := [binary()],
description := binary(),
options := [{Key :: atom(), OptionDescription :: binary()}]}.
plugin_info() ->
#{title => <<"Nova body plugin">>,
version => <<"0.0.1">>,
url => <<"https://github.com/novaframework/nova">>,
authors => [<<"Nova team <info@novaframework.org">>],
description => <<"This plugin modulates the body of a request.">>,
options => [
{decode_json_body, <<"Decodes the body as JSON and puts it under `json`">>},
{read_urlencoded_body, <<"Used to parse body as query-string and put them in state under `qs` key">>}
]
}.
%%%%%%%%%%%%%%%%%%%%%%
%% Private functions
%%%%%%%%%%%%%%%%%%%%%%
modulate_state(Req, [], State) ->
{ok, Req, State};
modulate_state( Req = #{method := Method}, [{decode_json_body, true}|Tail], State) when Method =:= <<"GET">>; Method =:= <<"DELETE">> ->
modulate_state(Req, Tail, State);
modulate_state(Req = #{headers := #{<<"content-type">> := <<"application/json", _/binary>>}, body := <<>>}, [{decode_json_body, true}|_Tl], State) ->
Req400 = cowboy_req:reply(400, Req),
logger:warning(#{status_code => 400,
msg => "Failed to decode json.",
error => "No body to decode."}),
{stop, Req400, State};
modulate_state(Req = #{headers := #{<<"content-type">> := <<"application/json", _/binary>>}, body := Body}, [{decode_json_body, true}|Tl], State) ->
%% Decode the data
JsonLib = nova:get_env(json_lib, thoas),
case JsonLib:decode(Body) of
{ok, JSON} ->
modulate_state(Req#{json => JSON}, Tl, State);
Error ->
Req400 = cowboy_req:reply(400, Req),
logger:warning(#{status_code => 400,
msg => "Failed to decode json.",
error => Error}),
{stop, Req400, State}
end;
modulate_state(#{headers := #{<<"content-type">> := <<"application/x-www-form-urlencoded", _/binary>>}, body := Body} = Req,
[{read_urlencoded_body, true}|Tl], State) ->
Data = cow_qs:parse_qs(Body),
%% First read in the body
Params = maps:from_list(Data),
modulate_state(Req#{params => Params}, Tl, State);
modulate_state(Req, [{parse_qs, Type}|T1], State) ->
Qs = cowboy_req:parse_qs(Req),
case Type of
true -> MapQs = maps:from_list(Qs),
modulate_state(Req#{parsed_qs => MapQs}, T1, State);
list -> modulate_state(Req#{parsed_qs => Qs}, T1, State)
end;
modulate_state(Req, [_|Tl], State) ->
modulate_state(Req, Tl, State).
%% A multipart body is never buffered here; nova_multipart_plugin or the
%% controller reads the parts from the stream.
read_request_body(Req, Options) ->
case not is_multipart(Req) andalso should_read_body(Options) andalso cowboy_req:has_body(Req) of
true -> read_body(Req, <<>>);
false -> Req#{body => <<>>}
end.
is_multipart(Req) ->
try cowboy_req:parse_header(<<"content-type">>, Req) of
{<<"multipart">>, <<"form-data">>, _Params} -> true;
_ -> false
catch
_:_ -> false
end.
read_body(Req, Acc) ->
case cowboy_req:read_body(Req) of
{ok, Data, Req0} -> Req0#{body => <<Acc/binary, Data/binary>>};
{more, Data, Req0} -> read_body(Req0, <<Acc/binary, Data/binary>>)
end.
should_read_body([]) -> false;
should_read_body([{decode_json_body, true}|_Tl]) -> true;
should_read_body([{read_urlencoded_body, true}|_Tl]) -> true;
should_read_body([_|Tl]) -> should_read_body(Tl).
-ifdef(TEST).
-compile(export_all).
-endif.