Hooks

Hooks are a way to execute custom code at specific points in the Serinus request lifecycle. They can be used to add custom logic to your application, such as tracing, loggin, or error handling.

Creating a Hook

To create a hook, you need to create a class that extends the Hook class. Each hook has multiple methods that you can override to add custom logic.

These are the methods that you can override:

Method	Description
onRequest	This method is called before the router is called.
beforeHandle	This method is called before the route handler is called.
afterHandle	This method is called after the route handler is called.
onResponse	This method is called after the response is generated.

import 'package:serinus/serinus.dart';

class MyHook extends Hook {
  @override
  Future<void> onRequest(Request request, InternalResponse response) async {
    print('Request received');
  }

  @override
  Future<void> beforeHandle(Request request, InternalResponse response) async {
    print('Before handle');
  }

  @override
  Future<void> afterHandle(Request request, InternalResponse response) async {
    print('After handle');
  }

  @override
  Future<void> onResponse(Response response) async {
    print('Response sent');
  }
}

In the MyHook class, you can override the methods that you want to add custom logic to. You can access the Request object and the InternalResponse object in the onRequest, beforeHandle, and afterHandle methods, and the Response object in the onResponse method.

The onResponse can also know if the response was successful or not by checking the response.isError property. This property will be true if the response status code is greater than or equal to 400.

Adding a Hook

To add a hook to your application, you can use the use method on the SerinusApplication object.

import 'package:serinus/serinus.dart';

void main(List<String> arguments) async {
  SerinusApplication application = await serinus.createApplication(
    entrypoint: AppModule()
  );
  application.use(MyHook());
  await application.serve();
}

In the example above, the MyHook hook is added to the application using the use method. This will execute the hook methods at the specified points in the request lifecycle.

Hooks are executed in the order that they are added to the application. If you need to execute a hook before another hook, you can add it before the other hook.