NestJS如何使用async/await配置中间件?

问题描述

我正在尝试在NestJS应用中使用斗牛竞技场.

I'm trying to use bull-arena in a NestJS app.

export class AppModule {
  configure(consumer: MiddlewareConsumer) {
    const queues = this.createArenaQueues();
    const arena = Arena({ queues }, { disableListen: true });
    consumer.apply(arena).forRoutes('/system/queues');
  }

  createArenaQueues() {
    return [
      {
        name: 'Notification_Emailer',
        hostId: 'MyAwesomeQueues',
        url: 'redis://localhost',
      },
    ];
}
}

这行得通！

但是由于从数据库中加载队列，我需要对createArenaQueues()使用async/await.

But I need to use async/await for createArenaQueues(), due to loading queues from db.

export class AppModule {
  configure(consumer: MiddlewareConsumer) {
    const queues = await this.createArenaQueues();   //await here
    const arena = Arena({ queues }, { disableListen: true });
    consumer.apply(arena).forRoutes('/system/queues');
  }

  async createArenaQueues() {                       // async here
    return [
      {
        name: 'Notification_Emailer',
        hostId: 'MyAwesomeQueues',
        url: 'redis://localhost',
      },
    ];
  }
}

不起作用！

那么，问题是，如何处理呢?

So, the question, how to handle this?

从系统"控制器运行竞技场很酷，但我想不出一种方法.

It wold be cool to run arena from "System" controller, but I couldn't figure out a way to do it.

此外，我尝试将竞技场移至独立的中间件，但不知道我最终应该做些什么:返回类似res.send(arena)之类的东西?

Also, I tried to move arena to standalone middleware, but dont know, what I should to do in the end: return something like res.send(arena) or what?

处理此问题的最简单方法是async配置支持，但未实现.

Easiest way to handle this, is async configure support, but it not implemented.

推荐答案

您可以创建为您的arenaQueues异步创建的自定义提供程序:

You can create a custom provider for your arenaQueues that is created asynchronously:

将自定义提供程序添加到您的AppModule的提供程序中:

Add the custom provider to your AppModule's providers:

providers: [
  ArenaService,
  {
    provide: 'arenaQueues',
    useFactory: async (arenaService: ArenaService) => arenaService.createArenaQueues(),
    inject: [ArenaService],
  },
],

，然后将arenaQueues注入您的AppModule:

export class AppModule {
  constructor(@Inject('arenaQueues') private queues) {}

  configure(consumer: MiddlewareConsumer) {
    // Now, you can use the asynchronously created this.queues here
    const arena = Arena({ queues: this.queues }, { disableListen: true });
    consumer.apply(arena).forRoutes('/system/queues');
  }

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