NestJS - Error: Unknown authentication strategy "local"

just add the PassportModule and LocalStrategy in app.module .it will be fixed

@Module({
  imports: [PassportModule],
  providers: [AuthService,LocalStrategy],
 })
 export class AppModule {}

Fix Bug https://github.com/nestjs/nest/issues/4646

File AUTH.ts

enter code here

import { Module } from '@nestjs/common';
import { JwtModule } from '@nestjs/jwt';
import { PassportModule } from '@nestjs/passport';
import { UserModule } from 'src/user/user.module';
import { JwtAuthController } from './jwt-auth.controller';
import { JwtAuthService } from './jwt-auth.service';
import { JwtStrategy } from './jwt.strategy';
import { LocalStrategy } from './local.strategy';

@Module({
imports: [
UserModule,
PassportModule.register({defaultStrategy:'local'}),
JwtModule.register({
  secret: process.env.SECRETKEY,
  signOptions: { expiresIn: '3600s' }
})
],
controllers: [JwtAuthController],
providers: [JwtAuthService, LocalStrategy, JwtStrategy],
exports: [JwtAuthService],
})
export class JwtAuthModule {}

Such an old question with no answers...

In my case I was having sort of an cyclic dependency issue. Or at least it was what it looked like. Cyclic deps can be either on nest side or even on node.js require side (on the second case we end up with empty imports).

Case 1:

@Injectable()
export class MyLocalStrategy extends PassportStrategy(PassportLocalStrategy) {
  hello = 'hello'

  constructor(private authService: AuthService) {
    console.log('load local strategy')
  }
}


@Module({
  imports: [
    CommonModule,
    PassportModule,
    JwtModule.registerAsync({
      async useFactory(config: ConfigService) {
        const jwtSecret = config.get('APP_KEY')
        const expiresIn = config.get('AUTH_TOKEN_EXPIRED')
        return {
          secret: jwtSecret,
          signOptions: {
            expiresIn,
          },
        }
      },
      inject: [ConfigService],
    }),
  ],
  providers: [
    RoleService,
    JwtStrategy,
    JwtService,
    AuthService,
  ],
  controllers: [AuthController],
  exports: [AuthService],
})
export class AuthModule {
  constructor(private moduleRef: ModuleRef) {}

  onModuleInit() {
    const moduleRef = this.moduleRef
    console.log('init auth module')
    const local = moduleRef.get(MyLocalStrategy)
    const auth = moduleRef.get(AuthService)
    console.log('my modules', { local, auth }, local?.hello)
  }
}

In this case the "load local strategy" never got logged. Yet "my modules" logged an empty localStrategy instance, without my "hello" property. Weird!

I hacked a fix by moving the class instantiation to a factory provider, and by requiring the dependencies with ModuleRef. The following excerpt worked fine.

@Module({
  imports: [
    CommonModule,
    PassportModule,
    JwtModule.registerAsync({
      async useFactory(config: ConfigService) {
        const jwtSecret = config.get('APP_KEY')
        const expiresIn = config.get('AUTH_TOKEN_EXPIRED')
        return {
          secret: jwtSecret,
          signOptions: {
            expiresIn,
          },
        }
      },
      inject: [ConfigService],
    }),
  ],
  providers: [
    RoleService,
    JwtStrategy,
    JwtService,
    AuthService,
    {
      provide: MyLocalStrategy,
      useFactory: (moduleRef: ModuleRef) => {
        const auth = moduleRef.get(AuthService)
        console.log('local strat factory', { auth })
        return new MyLocalStrategy(auth)
      },
      inject: [ModuleRef],
    },
  ],
  controllers: [AuthController],
  exports: [AuthService],
})
export class AuthModule {
  constructor(private moduleRef: ModuleRef) {}

  onModuleInit() {
    const moduleRef = this.moduleRef
    console.log('init auth module')
    const local = moduleRef.get(MyLocalStrategy)
    const auth = moduleRef.get(AuthService)
    console.log('local', { local, auth }, local?.hello)
  }
}

I also tried factory + injecting AuthService directly (through providers array, instead of using ModuleRef). I got a null AuthService.

Probably some dependency cycle on the node.js module imports, tough neither eslint or nest wouldn't say anything.

Check to see if your auth module is being imported in your entry file. app.module.ts.

My auth-module.ts

import { Module } from '@nestjs/common';
import { PassportModule } from '@nestjs/passport';
import { UsersModule } from 'src/users/users.module';
import { AuthService } from './auth.service';
import { LocalStrategy } from './local.strategy';

@Module({
 imports:[UsersModule,PassportModule],
 providers: [AuthService,LocalStrategy]
})
export class AuthModule {}

My app module

import { Module } from '@nestjs/common';
import { PassportModule } from '@nestjs/passport';
import { UsersModule } from 'src/users/users.module';
import { AuthService } from './auth.service';
import { LocalStrategy } from './local.strategy';

@Module({
  imports:[UsersModule,PassportModule],
 providers: [AuthService,LocalStrategy]
})
export class AuthModule {}

I have the same issue with you. My solution is importing LocalStrategy class to module file, in which I use AuthGuard for API endpoint.

For example: in file user.controller.ts I have AuthGuard('local') in the endpoint /login with method POST

//user.controller.ts

@UseGuards(AuthGuard('local'))
@Post('login')
async login (@Request() req: any) {
  return req.user;
}

In my case, I just add LocalStrategy class (I also have this class in local.strategy.ts like you) in module file:

//user.module.ts

@Module({
  imports: [
    ...
    LocalStrategy,
  ],
  controllers: [UserController],
  ...
}

Conclusion, NestJs is quite complicated in importing modules, don't forget to import what you want into other modules. Good luck!