Skip to main content

Message Mappers

DugongJS defines two message mapper ports that must be implemented when producing and consuming messages containing domain events:

  1. IInboundMessageMapper - maps messages containing domain events to domain events.
  2. IOutboundMessageMapper - maps domain events to messages.

By separating the inbound and outbound mappings, asymmetric message producing/consumption can be realized.

IInboundMessageMapper​

The responsibility of IInboundMessageMapper is to map messages coming from a message broker into domain events. It should be implemented like so:

import type { IInboundMessageMapper } from "@dugongjs/core";

export class InboundMessageMapper implements IInboundMessageMapper<TMessage> {
    // Implementation here...
}

Here, TMessage is the inbound message format.

IOutboundMessageMapper​

The responsibility of IOutboundMessageMapper is to map domain events to messages to prepare them for transit through a message broker. It should be implemented like so:

import type { IOutboundMessageMapper } from "@dugongjs/core";

export class InboundMessageMapper implements IOutboundMessageMapper<TMessage> {
    // Implementation here...
}

Here, TMessage is the outbound message format.