+/* Redirect any requests to a game ID at the top-level.
+ *
+ * Specifically, after obtaining the game ID (from the path) we simply
+ * lookup the game engine for the corresponding game and then redirect
+ * to the engine- and game-specific path.
+ */
+app.get('/[a-zA-Z0-9]{4}', (request, response) => {
+ const game_id = request.path.replace(/\//g, "");
+
+ const game = lmno.ids[game_id];
+ if (game === undefined) {
+ response.sendStatus(404);
+ return;
+ }
+ response.redirect(301, `/${game.engine}/${game.id}/`);
+});
+
+/* LMNO middleware to lookup the game. */
+app.use('/empires/:game_id([a-zA-Z0-9]{4})', (request, response, next) => {
+ request.game = lmno.ids[request.params.game_id].game;
+ if (request.game === undefined) {
+ response.sendStatus(404);
+ return;
+ }
+ next();
+});
+
+/* Mount sub apps. only _after_ we have done all the middleware we need. */
+app.use('/empires/[a-zA-Z0-9]{4}/', empires.app);
+