Rate limit example

example/rate_limit.dart

@@ -3,5 +3,27 @@ import 'package:angel_framework/http.dart';
 import 'package:angel_security/angel_security.dart';
 
 main() async {
+  // Create an app, and HTTP driver.
   var app = Angel(), http = AngelHttp(app);
+
+  // Create a simple in-memory rate limiter that limits users to 5
+  // queries per hour.
+  //
+  // In this case, we rate limit users by IP address.
+  var rateLimiter =
+      InMemoryRateLimiter(5, Duration(hours: 1), (req, res) => req.ip);
+
+  // `RateLimiter.handleRequest` is a middleware, and can be used anywhere
+  // a middleware can be used. In this case, we apply the rate limiter to
+  // *all* incoming requests.
+  app.fallback(rateLimiter.handleRequest);
+
+  // Basic routes.
+  app
+    ..get('/', (req, res) => 'Hello!')
+    ..fallback((req, res) => throw AngelHttpException.notFound());
+
+  // Start the server.
+  await http.startServer('127.0.0.1', 3000);
+  print('Rate limiting example listening at ${http.uri}');
 }