Middleware

React to incoming requests by modifying the request context

A Middleware is a Lifecycle Component that is used to modify the request or response before it reaches the endpoint.

Middleware is useful for binding data to the request context, transforming the request or response, and other tasks that need to be executed before the guard or endpoint.

Execution#

Middleware is executed before the guards, in the order they are registered.

Create a Middleware#

To create a Middleware, you need to implement the Middleware class and implement the use method.

lib/components/middleware/my_middleware.dart

import 'package:revali_router/revali_router.dart';

class MyMiddleware implements Middleware {
    const MyMiddleware();

    @override
    Future<MiddlewareResult> use(Context context) async {
        return const MiddlewareResult.next();
    }
}

Possible Results#

The MiddlewareResult has two possible results: next and stop. The next result allows the request to continue to the next middleware or guard. The stop result stops the request from continuing any further in the request flow.

const MiddlewareResult.next();

const MiddlewareResult.stop(
    statusCode: 400,
    headers: {},
    body: 'Bad Request',
);

Register the Middleware#

To register the Middleware, annotate your Middleware class on the app, controller, or endpoint level.

routes/controllers/my_controller.dart

import 'package:revali_router/revali_router.dart';

// highlight-next-line
@MyMiddleware()
@Get('')
Future<void> myEndpoint() {
    ...
}

Register as Type Reference#

routes/controllers/my_controller.dart

import 'package:revali_router/revali_router.dart';

// highlight-next-line
@Middlewares([MyMiddleware])
@Get('')
Future<void> myEndpoint() {
    ...
}