Map also success responses on Controllers

[acostapazo]

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Example Code

class CreateTaskController(FastAPIController):

    class Config:
        success_handler= lambda result: {"message": "Task saved"}
        error_map= {
           TaskAlreadyCreated: HttpError(status_code=409, detail="Task already created")
           TaskDescriptionTooLong: HttpError(status_code=422, detail="Task description is too long")
        }


    def execute(self, task: Task) -> BoolResult:
        task_creator = TaskCreator(
            labeler=Container.get(TaskLabeler),
            repository=Container.get(CrudRepository, alias="task_repository"),
            domain_event_bus=Container.get(DomainEventBus),
        )
        return task_creator.execute(task=task)

Description

With petisco you normally define success_handler and error_map to manage all the paths your use case can take.

In the above example:

• With success_handler: lambda result: {"message": "Task saved"} your program allways will return a 200 (default value) and the payload {"message": "Task saved"}.

• In case of failure, it will return 409 or 422 depending on the Failure returned by TaskCreator:
  * TaskAlreadyCreated -> 409
  * TaskDescriptionTooLong -> 422

But what if you want to have different behaviors for successful results?

Image we want to change the status code depending of the Success values is True or False. Now, we have to do it as following;

def my_example_success_handler(result: Result):
         if result.value is True:
                return JSONResponse(
                    status_code=status.HTTP_200_OK,
                    content={"message": "Task saved"}
                )
         else:
            return JSONResponse(
                status_code=status.HTTP_206_PARTIAL_CONTENT,
                content={"message": "Task will be saved"},
            )


class CreateTaskController(FastAPIController):

    class Config:
        success_handler= my_example_success_handler
        error_map= {
           TaskAlreadyCreated: HttpError(status_code=409, detail="Task already created")
           TaskDescriptionTooLong: HttpError(status_code=422, detail="Task description is too long")
        }


    def execute(self, task: Task) -> BoolResult:
        task_creator = TaskCreator(
            labeler=Container.get(TaskLabeler),
            repository=Container.get(CrudRepository, alias="task_repository"),
            domain_event_bus=Container.get(DomainEventBus),
        )
        return task_creator.execute(task=task)

The two solutions proposed below would have to take into account that these new mappings would be reflected in the static responses function, accessible in this example at: CreateTaskController.responses().

Proposal 1 (success_map)

Add a success_map similar to error_map and map success values.

class CreateTaskController(FastAPIController):

    class Config:
        success_map = {
               True: JSONResponse(status_code=200, content={"message": "Task saved"})
               False: JSONResponse(status_code=206, content={"message": "Task will be saved"})
        }
        error_map= {
           TaskAlreadyCreated: HttpError(status_code=409, detail="Task already created")
           TaskDescriptionTooLong: HttpError(status_code=422, detail="Task description is too long")
        }


    def execute(self, task: Task) -> BoolResult:
        task_creator = TaskCreator(
            labeler=Container.get(TaskLabeler),
            repository=Container.get(CrudRepository, alias="task_repository"),
            domain_event_bus=Container.get(DomainEventBus),
        )
        return task_creator.execute(task=task)

Proposal 2 (response_map)

Refactor the error_map and promote this to responses_map. In the case above will have to define a success alternative class with a domain class (e.g Success(AsynTaskQueued())

class CreateTaskController(FastAPIController):

    class Config:
        responses_map= {
           DEFAULT: JSONResponse(status_code=200, content={"message": "Task saved"}),
           False: JSONResponse(status_code=206, content={"message": "Task will be saved"})
           TaskAlreadyCreated: HttpError(status_code=409, detail="Task already created")
           TaskDescriptionTooLong: HttpError(status_code=422, detail="Task description is too long")
        }


    def execute(self, task: Task) -> BoolResult:
        task_creator = TaskCreator(
            labeler=Container.get(TaskLabeler),
            repository=Container.get(CrudRepository, alias="task_repository"),
            domain_event_bus=Container.get(DomainEventBus),
        )
        return task_creator.execute(task=task)