Skip to main content

Middleware ๐Ÿ”

Middleware in Dart Frog allows you to execute code before and after a request is processed. You can modify the inbound request and outbound responses, provide dependencies, and more!

In Dart Frog, a piece of middleware consists of a middleware function exported from a _middleware.dart file within a subdirectory of the routes folder. There can only ever be one piece of middleware per route directory with routes/_middleware.dart being middleware that is executed for all inbound requests.

import 'package:dart_frog/dart_frog.dart';

Handler middleware(Handler handler) {
return (context) async {
// Execute code before request is handled.

// Forward the request to the respective handler.
final response = await handler(context);

// Execute code after request is handled.

// Return a response.
return response;
};
}

We can chain built-in middleware, such as the requestLogger middleware via the use API. For example, if we create routes/_middleware.dart with the following contents, we will automatically log all requests to our server.

import 'package:dart_frog/dart_frog.dart';

Handler middleware(Handler handler) {
return handler.use(requestLogger());
}