Cancel a slot

We will now move into the territory of event-based side effects (and it's not a horror film!)

Canceling a slot is fun! Doing so means we have to do "event-based side effects" like opening it again, as a response to its cancellation.

Just as with checking in and out, we first need to verify and authorize the calling user. Also, again, we have API request validation active.

code/Reservation/Reservation/serverless.yml

CancelSlot:
  handler: src/infrastructure/adapters/web/CancelSlot.handler
  description: Cancel a slot
  events:
    - http:
        method: POST
        path: /CancelSlot
        authorizer:
          name: Authorizer
          resultTtlInSeconds: ${self:custom.config.apiGatewayCachingTtlValue}
          identitySource: method.request.header.Authorization
          type: request
        request:
          schemas:
            application/json: ${file(schema/Id.validator.json)}

In our use case, we will again use the convenience service called SlotLoaderService, rather than the Reposi

code/Reservation/Reservation/src/application/usecases/CancelSlotUseCase.ts

export async function CancelSlotUseCase(
  dependencies: Dependencies,
  slotId: SlotId
): Promise<void> {
  const slotLoader = createSlotLoaderService(dependencies.repository);
  const slotDto = await slotLoader.loadSlot(slotId);

  const reservationService = new ReservationService(dependencies);
  await reservationService.cancel(slotDto);
}

The pattern should be quite familiar by now.