RabbitMQ consumer

Basic usage.

1. Add new ConsumerConfig to the ServiceProvider.
2. Create a new Message
3. Create a new RequestHandler for your new incoming message
4. Create a new Consumer class, which extends the abstract Consumer class.
5. Inject the new consumer into the Application class and call the consumer with the RabbitMQ connection.
6. Testing the consumer

1. ConsumerConfig | ./src/Providers/ServiceProvider.ts

.provideValue("ExampleConsumerConfig", {
    queue: "example_queue",
  } as ConsumerConfig)

2a. Message payload | ./src/Payloads/ExamplePayload.ts

@Serializable() // <-- TS-jackson serializer
export default class ExamplePayload {
  @JsonProperty("title")
  readonly title?: string;
}

2b. Message | ./src/Messages/ExampleMessage.ts

export default class ExampleMessage extends Message<ExamplePayload> {}

3a. RequestHandler | ./src/RequestHandlers/ExampleRequestHandler.ts

export default class ExampleRequestHandler implements RequestHandler {
  public async handle(message: ConsumeMessage): Promise<void> {
    const exampleMessage = deserialize(
      message.content.toString(),
      ExampleMessage
    ); // <-- TS-jackson deserializer

    console.log(exampleMessage);
  }
}

3b. RequestHandler injection | ./src/RequestHandlers/ExampleRequestHandler.ts

// register the service provider
const provider = new ServiceProvider().register();
// resolve the class by it's identifier
const logger = provider.resolve("Logger");
logger.info("Successfully injected the Logger");

4. Consumer | ./src/Consumers/ExampleConsumer.ts

export default class ExampleConsumer extends Consumer {
  public static inject = [
    "ExampleRequestHandler", // <-- The new RequestHandler
    "ExampleConsumerConfig", // <-- The new ConsumerConfig
  ] as const;

  public constructor(
    private readonly requestHandler: RequestHandler,
    protected readonly config: ConsumerConfig
  ) {
    super(config);
  }

  public handler() {
    return this.requestHandler.handle; // Just return the handle method
  }
}

5. Execute the consumer | ./src/Infrastructure/Application.ts

await this.exampleConsumer.consume(connection);

6. Testing the consumer

• Run yarn fake to send 10 fake message to the example_queue.