NestJS 从 ExceptionFilter 抛出

Question

我尝试使用 anExceptionFilter将异常映射到它们的 HTTP 对应项。

这是我的代码：

@Catch(EntityNotFoundError)
export class EntityNotFoundFilter implements ExceptionFilter {
    catch(exception: EntityNotFoundError, _host: ArgumentsHost) {
        throw new NotFoundException(exception.message);
    }
}

但是，当执行过滤器代码时，我得到了一个 UnhandledPromiseRejectionWarning

 (node:3065) UnhandledPromiseRejectionWarning: Error: [object Object]
    at EntityNotFoundFilter.catch ([...]/errors.ts:32:15)
    at ExceptionsHandler.invokeCustomFilters ([...]/node_modules/@nestjs/core/exceptions/exceptions-handler.js:49:26)
     at ExceptionsHandler.next ([...]/node_modules/@nestjs/core/exceptions/exceptions-handler.js:13:18)
     at [...]/node_modules/@nestjs/core/router/router-proxy.js:12:35
     at <anonymous>
     at process._tickCallback (internal/process/next_tick.js:182:7)
 (node:3065) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 5)

我怎样才能解决这个问题 ？

Answer 1

该ExceptionFilter总是被调用送出响应之前，它负责构建响应最后的地方。您不能从ExceptionFilter.

@Catch(EntityNotFoundError)
export class EntityNotFoundFilter implements ExceptionFilter {
  catch(exception: EntityNotFoundError, host: ArgumentsHost) {
    const response = host.switchToHttp().getResponse();
      response.status(404).json({ message: exception.message });
  }
}

或者，您可以创建一个Interceptor来转换您的错误：

@Injectable()
export class NotFoundInterceptor implements NestInterceptor {
  intercept(context: ExecutionContext, next: CallHandler): Observable<any> {
    // next.handle() is an Observable of the controller's result value
    return next.handle()
      .pipe(catchError(error => {
        if (error instanceof EntityNotFoundError) {
          throw new NotFoundException(error.message);
        } else {
          throw error;
        }
      }));
  }
}

在这个codeandbox 中尝试一下。

Answer 2

这里的关键是将BaseExceptionFilter和委托扩展到超类而不是抛出：

import { BaseExceptionFilter } from '@nestjs/core';
// .. your other imports

@Catch(EntityNotFoundError)
export class EntityNotFoundFilter extends BaseExceptionFilter {
    catch(exception: EntityNotFoundError, host: ArgumentsHost) {
        super.catch(new NotFoundException(exception.message, host));
    }
}

applicationRef在应用程序引导期间构造过滤器时，请务必传入参数，因为BaseExceptionFilter需要此属性才能正确运行

import { HttpAdapterHost } from '@nestjs/core';
// .. your other imports

async function bootstrap(): Promise<void> {
  // .. blah blah
  const { httpAdapter } = app.get(HttpAdapterHost);
  app.useGlobalFilters(new GeneralErrorFilter(httpAdapter));
  // .. blah blah
}

如果您抛出相同的错误，这将导致您将收到的默认错误处理。