+ const game_id = lmno.create_game(game_engine);
+ response.send(JSON.stringify(game_id));
+});
+
+/* 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 canon_id = lmno_canonize(game_id);
+
+ /* Redirect user to page with the canonical ID in it. */
+ if (game_id !== canon_id) {
+ response.redirect(301, `/${canon_id}/`);
+ return;
+ }
+
+ const game = lmno.ids[game_id];
+ if (game === undefined) {
+ response.sendStatus(404);
+ return;
+ }
+ response.redirect(301, `/${game.engine}/${game.id}/`);
+});
+
+/* LMNO middleware to lookup the game. */
+app.use('/:engine([^/]+)/:game_id([a-zA-Z0-9]{4})', (request, response, next) => {
+ const engine = request.params.engine;
+ const game_id = request.params.game_id;
+ const canon_id = lmno_canonize(game_id);
+
+ /* Redirect user to page with the canonical ID in it, also ensuring
+ * that the game ID is _always_ followed by a slash. */
+ const has_slash = new RegExp(`^/${engine}/${game_id}/`);
+ if (game_id !== canon_id ||
+ ! has_slash.test(request.originalUrl))
+ {
+ const old_path = new RegExp(`/${engine}/${game_id}/?`);
+ const new_path = `/${engine}/${canon_id}/`;
+ const new_url = request.originalUrl.replace(old_path, new_path);
+ response.redirect(301, new_url);
+ return;
+ }
+
+ /* See if there is any game with this ID. */
+ const game = lmno.ids[game_id];
+ if (game === undefined) {
+ response.sendStatus(404);
+ return;
+ }
+
+ /* Stash the game onto the request to be used by the game-specific code. */
+ request.game = game.game;
+ next();
+});
+
+function auth_admin(request, response, next) {
+ /* If there is no user associated with this session, redirect to the login
+ * page (and set a "next" query parameter so we can come back here).
+ */
+ if (! request.session.user) {
+ response.redirect(302, "/login?next=" + request.path);
+ return;
+ }
+
+ /* If the user is logged in but not authorized to view the page then
+ * we return that error. */
+ if (request.session.user.role !== "admin") {
+ response.status(401).send("Unauthorized");
+ return;
+ }
+ next();
+}
+
+app.get('/logout', (request, response) => {
+ request.session.user = undefined;
+ request.session.destroy();
+
+ response.send("You are now logged out.");