%% Feel free to use, reuse and abuse the code in this file.
-module(directory_lister).
-behaviour(cowboy_middleware).
-export([execute/2]).
execute(Req, Env=#{handler := cowboy_static}) ->
redirect_directory(Req, Env);
execute(Req, Env) ->
{ok, Req, Env}.
redirect_directory(Req, Env=#{handler_opts := {_, _, _, Extra}}) ->
Path = cowboy_req:path_info(Req),
Path1 = << <<S/binary, $/>> || S <- Path >>,
{dir_handler, DirHandler} = lists:keyfind(dir_handler, 1, Extra),
FullPath = resource_path(Path1),
case valid_path(Path) and filelib:is_dir(FullPath) of
true -> handle_directory(Req, Env, Path1, FullPath, DirHandler);
false -> {ok, Req, Env}
end.
handle_directory(Req, Env, Prefix, Path, DirHandler) ->
{ok, Req, Env#{handler => DirHandler, handler_opts => {Prefix, Path}}}.
valid_path([]) -> true;
valid_path([<<"..">> | _T]) -> false;
valid_path([<<"/", _/binary>> | _T]) -> false;
valid_path([_H | Rest]) -> valid_path(Rest).
resource_path(Path) ->
filename:join([code:priv_dir(file_server), Path]).