@aarek/nest-stan 中文文档教程

Question

@aarek/nest-stan

Table of Contents

• Description
• Usage
• Install
• Module Initialization
• Handling Messages
• Publishing Messages
• Connection Status
• ToDo

Description

包装 node-nats-streaming 用于 NestJS.

Usage

Install

npm install --save @aarek/nest-stan

或

yarn add @aarek/nest-stan

Module initialization

@Module({
  imports: [
    NestStanModule.forRoot({
      clientId: 'client-id-test1',
      clusterId: 'test-cluster',
      stanOptions: {
        url: 'nats://localhost:4222'
      }
    })
  ]
})
export class AppModule {}

或

@Module({
  imports: [
    NestStanModule.forRootAsync({
      imports: [ConfigModule]
      inject: [ConfigService],
      useFactory: (config: ConfigService) => config.nestStanConfig(),
    }),
  ]
})
export class AppModule {}

Handling messages

Nest Stan 为您提供两个装饰器 StanSubscribe 和<代码>AsyncStanSubscribe。 AsyncStanSubscribe 将在 Promise 解析成功后自动确认消息。 两个装饰器都接受 subject 作为第一个参数和可选的 OptionsBuilder 作为第二个参数。 OptionsBuilder 是一个接受 node-nats-streaming SubscriptionOptions 的函数，应该返回 SubscriptionOptions。

例如：

@StanSubscribe('subject', options =>
  options.setStartAtTimeDelta(30 * 1000),
)
export class Subscriber implements IStanSubscriber<Message> {
  handle(message: Message, context: IMessageHandlerContext): void {
    // Handle message
    return;
  }
}

@AsyncStanSubscribe('subject', options =>
  options
    .setStartAtTimeDelta(30 * 1000)
    .setDurableName(AsyncSubscriber.name),
)
export class AsyncSubscriber implements IStanSubscriber<Message> {
  async handle(message: Message, context: IMessageHandlerContext): Promise<void> {
    // Handle message
    return;
  }
}

Publishing messages

为了发布消息，您首先需要为要发布的主题导入 NestStanModule：

@Module({
  imports: [NestStanModule.forSubjects(['subject'])],
  controllers: [TestController],
  providers: [],
})
export class TestModule {}

Nest Stan 为您提供 InjectPublisher 装饰器以注入发布者：

@Controller()
class TestController {
  constructor(
    @InjectPublisher('subject') private readonly publisher: IStanPublisher<Message>,
  ) {}

  @Post()
  async publishMessage() {
    const message: Message = {
      foo: 'bar',
    }

    await this.publisher.publish(message)
  }
}

Connection status

在为了检查当前的连接状态，您可以使用 InjectConnectionStatusIndicator：

@Injectable()
export class StanConnectionIndicator extends HealthIndicator {
  constructor(
    @InjectConnectionStatusIndicator() private readonly connectionStatus: ConnectionStatusIndicator
  ) {
    super();
  }

  async isHealthy(key: string): Promise<HealthIndicatorResult> {
    const isHealthy = this.connectionStatus.getStatus() === ConnectionStatus.CONNECTED;
    const lastError = this.connectionStatus.lastError()

    return this.getStatus(key, isHealthy, { lastError });
  }
}

ToDo

• [ ] Add linter
• [ ] Add classes documentation
• [ ] Implement github actions
• [ ] Collect coverage
• [ ] Provide example app