Nestjs Exception / validation

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31

// nest/packages/core/exceptions/base-exception-filter.ts

export class BaseExceptionFilter<T = any> implements ExceptionFilter<T> {
  // ...
  catch(exception: T, host: ArgumentsHost) {
    // ...
    if (!(exception instanceof HttpException)) {
      return this.handleUnknownError(exception, host, applicationRef);
    }
    const res = exception.getResponse();
    const message = isObject(res)
      ? res
      : {
          statusCode: exception.getStatus(),
          message: res,
        };
    // ...
  }
 
  public handleUnknownError(
    exception: T,
    host: ArgumentsHost,
    applicationRef: AbstractHttpAdapter | HttpServer,
  ) {
    const body = {
      statusCode: HttpStatus.INTERNAL_SERVER_ERROR,
      message: MESSAGES.UNKNOWN_EXCEPTION_MESSAGE,
    };
    // ...
  }
}

 1
 2
 3
 4
 5
 6
 7
 8
 9
10

import { Catch, ArgumentsHost } from '@nestjs/common';
import { BaseExceptionFilter } from '@nestjs/core';
 
@Catch()
export class ExceptionsLoggerFilter extends BaseExceptionFilter {
  catch(exception: unknown, host: ArgumentsHost) {
    console.log('Exception thrown', exception);
    super.catch(exception, host);
  }
}

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16

import { HttpAdapterHost, NestFactory } from '@nestjs/core';
import { AppModule } from './app.module';
import * as cookieParser from 'cookie-parser';
import { ExceptionsLoggerFilter } from './utils/exceptionsLogger.filter';
 
async function bootstrap() {
  const app = await NestFactory.create(AppModule);
 
  const { httpAdapter } = app.get(HttpAdapterHost);
  app.useGlobalFilters(new ExceptionsLoggerFilter(httpAdapter));
 
  app.use(cookieParser());
  await app.listen(3000);
}
bootstrap();

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14

import { Module } from '@nestjs/common';
import { ExceptionsLoggerFilter } from './utils/exceptionsLogger.filter';
import { APP_FILTER } from '@nestjs/core';
 
@Module({
  // ...
  providers: [
    {
      provide: APP_FILTER,
      useClass: ExceptionsLoggerFilter,
    },
  ],
})
export class AppModule {}

1
2
3
4
5

@Get(':id')
@UseFilters(ExceptionsLoggerFilter)
getPostById(@Param('id') id: string) {
  return this.postsService.getPostById(Number(id));
}