Nest 无法解析 CommonModule 的依赖关系

Question

I'm new in NEST.js world, and I trying to create simple middleware. First, I created a middleware with this command:

nest g middleware common/middleware/logging

And after I add my code

import { Injectable, NestMiddleware } from '@nestjs/common';

@Injectable()
export class LoggingMiddleware implements NestMiddleware {
  use(req: any, res: any, next: () => void) {
    console.time('Request-response time');
    console.log('Hi from middleware!');

    res.on('finish', () => console.timeEnd('Request-response time'));
    next();
  }
}

And finally, I add the middleware

import { Module, MiddlewareConsumer } from '@nestjs/common';
import { APP_GUARD } from '@nestjs/core';
import { ApiKeyGuard } from './guards/api-key.guard';
import { ConfigModule } from '@nestjs/config';
import { LoggingMiddleware } from './middleware/logging.middleware';

@Module({
  imports: [
    ConfigModule
  ],
  providers: [
    {
      provide: APP_GUARD,
      useClass: ApiKeyGuard
    }

  ]
})
export class CommonModule {
  constructor(consumer: MiddlewareConsumer) {
    consumer.apply(LoggingMiddleware).forRoutes('*')
  }
}

But when i try to run it:

Nest can't resolve dependencies of the CommonModule (?). Please make sure that the argument Object at index [0] is available in the CommonModule context.

Potential solutions:

• If Object is a provider, is it part of the current CommonModule?
• If Object is exported from a separate @Module, is that module imported within CommonModule? @Module({ imports: [ /* the Module containing Object */ ] }) +2ms Error: Nest can't resolve dependencies of the CommonModule (?). Please make sure that the argument Object at index [0] is available in the CommonModule context.

Potential solutions:

• If Object is a provider, is it part of the current CommonModule?
• If Object is exported from a separate @Module, is that module imported within CommonModule? @Module({ imports: [ /* the Module containing Object */ ] })

Can you help me?

Answer 1

The MiddlewareConsumer isn't a part of the constructor . Rather, your module class should implement NestModule and should have a configure method that takes in the consumer: MiddlewareConsumer as the first and only paramter.

@Module({
  imports: [
    ConfigModule
  ],
  providers: [
    {
      provide: APP_GUARD,
      useClass: ApiKeyGuard
    }

  ]
})
export class CommonModule implmenets NestModule {
  configure(consumer: MidlewareConsumer) {
    consumer.apply(LoggingMiddleware).forRoutes('*')
  }
}