Class TransactionalInboxMessageHandler<TMessage, TConfig, TContext>Abstract

constructor

• new TransactionalInboxMessageHandler<TMessage, TConfig, TContext>(messagingSettings, logger, config, handlePreprocessor?): TransactionalInboxMessageHandler<TMessage, TConfig, TContext>

• Create a new Message handler that provides both the functionality to store an incoming RabbitMQ message in the inbox and provides the actual logic to execute the business logic that is based on that message.

  Type Parameters

  • TMessage

  • TConfig

  • TContext extends Dict<unknown, TContext> = Dict<unknown>

  Parameters

  • messagingSettings: MessagingSettings

    The definitions of the message that is handled.

  • logger: InboxOutboxLogger

  • config: TConfig

    The service configuration object

  • Optional handlePreprocessor: HandlePreprocessor<TMessage, TContext>

    A preprocessor that is called before the handleMessage and handleErrorMessagemethods. It can be used for validations and to provide an optional context.

  Returns TransactionalInboxMessageHandler<TMessage, TConfig, TContext>

Readonly aggregateType

Readonly messageType

handle

• handle(message, envOwnerClient): Promise<void>

• Is called from the transactional inbox and calls the abstract handleMessage function with the correct message payload typing. Do not override this message but implement the handleMessage message.

  Parameters

  • message: StoredTransactionalMessage

    The inbox message with the payload to handle.

  • envOwnerClient: DatabaseClient

    The database client that is part of a DB env owner transaction to safely handle the inbox message.

  Returns Promise<void>

handleError

• handleError(error, message, envOwnerClient, retry): Promise<void>

• Is called from the transactional inbox and calls the handleErrorMessage function with the correct message payload typing. Do not override this message but override the handleErrorMessage message.

  Parameters

  • error: Error

    The error that was thrown in the handle method.

  • message: StoredTransactionalMessage

    The inbox message with the payload that was attempted to be handled.

  • envOwnerClient: DatabaseClient

    The database client that is part of a (new) transaction to safely handle the error.

  • retry: boolean

    True if the message will be retried again.

  Returns Promise<void>

  A flag that defines if the message should be retried ('transient_error') or not ('permanent_error')

handleErrorMessage

• handleErrorMessage(error, message, _envOwnerClient, retry, _context?): Promise<void>

• Optionally override this method with your custom business logic to handle an error that was caused by the handleMessage method. The default implementation logs the error if there are no further retries.

  Parameters

  • error: Error

    The error that was thrown in the handleMessage method.

  • message: TypedTransactionalMessage<TMessage>

    The inbox message with the payload that was attempted to be handled.

  • _envOwnerClient: DatabaseClient

  • retry: boolean

    True if the message will be retried again.

  • Optional _context: TContext

  Returns Promise<void>

Abstract handleMessage

• handleMessage(message, envOwnerClient, context?): Promise<void>

• Implement to execute your custom business logic to handle a message that was stored in the inbox.

  Parameters

  • message: TypedTransactionalMessage<TMessage>

    The inbox message with the payload to handle.

  • envOwnerClient: DatabaseClient

    The database client that is part of a DB env owner transaction to safely handle the inbox message.

  • Optional context: TContext

  Returns Promise<void>

  Throws

  If something fails and the inbox message should NOT be acknowledged - throw an error.

mapError

• mapError(error): Error

• Function to map a thrown error of an unspecified type to a potentially more human-readable error or remove unsafe properties.

  Parameters

  • error: Error

  Returns Error