1 files changed, 32 insertions, 0 deletions
diff --git a/examples/file_server/src/directory_lister.erl b/examples/file_server/src/directory_lister.erl
new file mode 100644
index 0000000..2ca9d30
--- /dev/null
+++ b/examples/file_server/src/directory_lister.erl
@@ -0,0 +1,32 @@
+%% 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]).