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Cannot read property 'ip' of undefined when testing rate limiting on nest.js

September 18, 2022

So I have the following configured in my nest.js graphql applicaiton, which seems to be working;

@Module({
  imports: [
    ThrottlerModule.forRootAsync({
      imports: [ConfigModule],
      inject: [ConfigService],
      useFactory: (config: ConfigService) => ({
        ttl: config.get('THROTTLE_TTL'),
        limit: config.get('THROTTLE_LIMIT'),
      }),
    }),
  ],
  providers: [
    {
      provide: APP_GUARD,
      useClass: ThrottlerGuard,
    },
  ],
})
export class AppModule {}

but when I try to load test against my local server, the dropped requests all raise the following error

[Nest] 3177  - 2022-09-18T16:25:36.188Z   ERROR [ExceptionsHandler] Cannot read property 'ip' of undefined
TypeError: Cannot read property 'ip' of undefined

Why is the request handler not able to capture IP address? Is it b/c its going through one localhost to another?

>Solution :

As the documentation shows the ThrottlerGuard needs to be extended to make the getRequestResponse method return the correct values so that the ip and headers objects can be referenced properly.

@Injectable()
export class GqlThrottlerGuard extends ThrottlerGuard {
  getRequestResponse(context: ExecutionContext) {
    const gqlCtx = GqlExecutionContext.create(context);
    const ctx = gqlCtx.getContext();
    return { req: ctx.req, res: ctx.res };
  }
}