-module(nova_cors_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()}.
pre_request(Req, _Env, #{allow_origins := Origins}, State) ->
ReqWithOptions = add_cors_headers(Req, Origins),
continue(ReqWithOptions, 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, _Opts, 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_cors_plugin">>,
version => <<"0.2.0">>,
url => <<"https://github.com/novaframework/nova">>,
authors => [<<"Nova team <info@novaframework.org">>],
description => <<"Add CORS headers to request">>,
options => [
{allow_origins, <<"Specifies which origins to insert into Access-Control-Allow-Origin">>}
]
}.
%%%%%%%%%%%%%%%%%%%%%%
%% Private functions
%%%%%%%%%%%%%%%%%%%%%%
continue(#{method := <<"OPTIONS">>} = Req, State) ->
Reply = cowboy_req:reply(200, Req),
{stop, Reply, State};
continue(Req, State) ->
{ok, Req, State}.
add_cors_headers(Req, Origins) ->
OriginsReq = cowboy_req:set_resp_header(
<<"Access-Control-Allow-Origin">>, Origins, Req),
HeadersReq = cowboy_req:set_resp_header(
<<"Access-Control-Allow-Headers">>, <<"*">>, OriginsReq),
cowboy_req:set_resp_header(
<<"Access-Control-Allow-Methods">>, <<"*">>, HeadersReq).