angular - 如何将 REQUEST 范围服务的实例传递给全局拦截器

Question

我在后端使用 Nest JS。我有日志服务 scoped.Request

@Injectable({ scope: Scope.REQUEST })
export class LoggingService extends BaseLoggerService implements LoggerService {
  constructor(readonly configService: ConfigurationService, @Inject(RequestContextService) readonly requestContextService: IRequestContextService) {}

我有需要日志记录服务的全局拦截器。

@Injectable()
export class LoggingInterceptor implements NestInterceptor {
    constructor(@Inject(LoggingService) private readonly logger: LoggingService) {
    }  }

现在在 app.ts 中，我试图定义 useGlobalInterceptors 绕过 Logging service 的实例。但是，它会在 npm run start 上抛出错误。

app.useGlobalInterceptors(new LoggingInterceptor(app.get(LoggingService)));

错误

2020-02-20T10:51:54.409Z ERROR [object Object] (RID:NOT_SET RP:NOT_SET TK:) (AN:NOT_SET COM:NOT_SET UAN:NOT_SET) LoggingService is marked as a scoped provider. Request and transient-scoped providers can't be used in combination with "get()" method. Please, use "resolve()" instead. Error: LoggingService is marked as a scoped provider. Request and transient-scoped providers can't be used in combination with "get()" method. Please, use "resolve()" instead.

Answer 1

作为错误状态，作为 LoggerService是REQUEST作用域，你需要使用 await app.resolve<LoggingService>(LoggingService) ，但是，您可能想要做的是全局绑定(bind)拦截器，并让 Nest 通过将拦截器添加到 providers 来处理依赖项注入(inject)。像这样的数组:

@Module({
  imports: [...],
  providers: [
    {
      provide: APP_INTERCEPTOR,
      useClass: LoggingInterceptor
    },
    ...
  ]
})
export class AppModule {}

需要记住的是，拦截器已经拥有了整个请求上下文。此外，我不确定如果增强器变成 REQUEST 范围(如果它具有 REQUEST 范围的依赖项将会发生什么)，它们将如何工作，所以请记住，这可能不是最好的前进路线。