Middlewares and Params

Middlewares

How middleware works?

How middleware works

When the bot gets update, it completes all middlewares, and only then completes a handler. For example, using middlewares, you can auth user and pass some params to the handler

Creating middleware

Let's create logger.middleware.ts file. It will be the middleware that will log received update. We will then apply this middleware

You can move middleware to different position

You can read more about Answer class here

logger.middleware.ts

export function LoggerMiddleware(
  update: IUpdate, // received update
  answer: Answer, // Answer (you can send a message)
  params: any, // Params (you can pass params to the handler)
  next: NextFunction, // next function (it can be next middleware or handler)
  fail: NextFunction, // fail function (you need to call it if you don't want to call handler)
) {
  params.someParam = 1; // set some param that we want to get in handler
  console.log(update); // log received update
  next(); // call handler
}

app.controller.ts

import { OnText, Controller, Params } from 'nestgram';
import { LoggerMiddleware } from './logger.middleware';
import { AppService } from './app.service';

@Controller()
export class AppController {
  constructor(private readonly appService?: AppService) {}

  @OnText()
  @Middleware(LoggerMiddleware)
  async handleText(@Params() params: any): Promise<string> {
    console.log(params);
    return 'Hello, world!';
  }
}

Global middlewares

You can apply middleware for all controller, if you are uncomfortable to set it for every handler

app.module.ts

import { Module } from 'nestgram';
import { LoggerMiddleware } from './logger.middleware.ts';

import { AppController } from './app.controller';
import { AppService } from './app.service';

@Module({
  controllers: [AppController],
  services: [AppService],
  middlewares: [LoggerMiddleware],
})
export class AppModule {}