How to inject middleware provider into loopback sequence

Question

I'm following documentation here and I want to write a middleware in loopback to log all requests. I write this Middleware provider:

@injectable(
  asMiddleware({
    group: 'log',
    upstreamGroups: ['sendResponse'],
    chain: RestTags.REST_MIDDLEWARE_CHAIN,
  }),
)
export class LogMiddlewareProvider
  implements Provider<Middleware> {
  value(): Middleware {
    return async (ctx, next) => {
      const {request} = ctx
      try {
        console.log(request.method);
        const result = await next();
        return result;
      } catch (err) {
        console.log(err);
        throw err;
      }
    }
  }
}

But I can not find in documentation that how I can use this provider and how can I inject this into sequence or in my application

Answer 1

You can register it in the application.ts by importing and then registering it with the application in the constructor. Here is the example

....
import { LogMiddlewareProvider } from './middleware/another.middleware';
export class SampleAppApplication extends BootMixin(
ServiceMixin(RepositoryMixin(RestApplication)),
) {
    constructor(options: ApplicationConfig = {}) {
      super(options);
      // the middleware is being registered here,
      this.middleware(LogMiddlewareProvider);
      // Set up the custom sequence
      this.sequence(MySequence);

      // Set up default home page
      this.static('/', path.join(__dirname, '../public'));

      // Customize @loopback/rest-explorer configuration here
      this.configure(RestExplorerBindings.COMPONENT).to({
        path: '/explorer',
      });
      this.component(RestExplorerComponent);
      this.projectRoot = __dirname;
      // Customize @loopback/boot Booter Conventions here
      this.bootOptions = {
        controllers: {
          // Customize ControllerBooter Conventions here
          dirs: ['controllers'],
          extensions: ['.controller.js'],
          nested: true,
      },
   };
   this.component(CrudRestComponent);
  }
}