在 Nestjs 的过滤器中注入服务

Question

我正在尝试在我创建的以下异常处理程序中注入nestjs-config ：

import { ExceptionFilter, Catch, ArgumentsHost, Injectable } from '@nestjs/common';
import { HttpException } from '@nestjs/common';
import { InjectConfig } from 'nestjs-config';

@Injectable()
@Catch()
export class HttpExceptionFilter implements ExceptionFilter {
  constructor(
    @InjectConfig()
    private readonly config,
  ) {
    this.config = config.get('errors');
  }
  catch(exception: HttpException, host: ArgumentsHost) {
    // some code here that calls this.config
  }
}

但它返回未定义：类型错误TypeError: Cannot read property 'get' of undefined

这是异常处理程序的全局定义方式：

const app = await NestFactory.create(AppModule, { cors: true });
app.useGlobalFilters(new HttpExceptionFilter());
await app.listen(3000);

Answer 1

好的，我刚刚意识到在您的代码中您正在容器外部创建过滤器，因此未注入 ConfigService。 有几种方法可以解决这个问题。 一

ConfigService.load(path.resolve(__dirname, 'config', '*.ts'))

const app = await NestFactory.create(AppModule, { cors: true });
app.useGlobalFilters(new HttpExceptionFilter(ConfigService));
await app.listen(3000);

或者

const app = await NestFactory.create(AppModule, {cors: true});
const config = app.get<ConfigService>(ConfigService);
app.useGlobalFilters(new HttpExceptionFilter(config));
await app.listen(3000);

取决于你的 AppModule 看起来像这样

@Module({
    imports: [ConfigModule.load(path.resolve(__dirname, 'config', '*.ts')],
})
export AppModule {}

或者像这样：

const app = await NestFactory.create(AppModule, {cors: true});
const httpExceptionFilter = app.get(HttpExpectionFilter);
app.useGlobalFilters(httpExpectionFilter);

Answer 2

通过调用 ConfigService 来解决它，如下所示：

export class HttpExceptionFilter implements ExceptionFilter {

  constructor(private readonly config: ConfigService) {
    this.config = ConfigService.get('errors');
  }
  catch(exception: HttpException, host: ArgumentsHost) {
    // some code here that calls this.config
  }
}

Answer 3

对于 Nestjs V8，您可以将其放在 AppModule 提供程序中：

{
  provide: APP_FILTER,
  useClass: HttpExceptionFilter,
},