Reference

fastapi_mock_middleware.MockAPIMiddleware

MockAPIMiddleware(app, not_implemented_error_class=APINotImplementedError, content_mocked_header_name='X-Content-Mocked', default_list_size=10)

Mock API middleware

Mocks unimplemented endpoint responses with generated data according to their response models.

PARAMETER	DESCRIPTION
app	ASGI application
not_implemented_error_class	Exception class on raising which middleware returns mocked response: Default: APINotImplementedError. It's not encouraged to use the built-in NotImplementedError not to confuse with the one intended for API mocking. TYPE: Exception DEFAULT: APINotImplementedError
content_mocked_header_name	response header name indicating that the response has been mocked. Default: X-Content-Mocked TYPE: str DEFAULT: 'X-Content-Mocked'
default_list_size	List size to generate for list responses. TYPE: int DEFAULT: 10

Usage example

app = FastAPI()
app.add_middleware(MockAPIMiddleware)

Usage example with arguments

app = FastAPI()
app.add_middleware(
    MockAPIMiddleware,
    not_implemented_error_class=APINotImplementedError,
    content_mocked_header_name='X-Content-Mocked',
    default_list_size=10,
)

Source code in fastapi_mock_middleware/middleware.py

def __init__(
        self,
        app,
        not_implemented_error_class: Exception = APINotImplementedError,
        content_mocked_header_name: str = 'X-Content-Mocked',
        default_list_size: int = 10,
):
    """
    Mock API middleware

    Mocks unimplemented endpoint responses with generated data according
    to their response models.

    Args:
        app: ASGI application
        not_implemented_error_class: Exception class on raising which
            middleware returns mocked response: Default:
            `APINotImplementedError`. It's not encouraged to use the
            built-in NotImplementedError not to confuse with the one
            intended for API mocking.
        content_mocked_header_name: response header name indicating that the
            response has been mocked. Default: `X-Content-Mocked`
        default_list_size: List size to generate for list responses.

    Usage example:
        ```python
        app = FastAPI()
        app.add_middleware(MockAPIMiddleware)
        ```

    Usage example with arguments:
        ```python
        app = FastAPI()
        app.add_middleware(
            MockAPIMiddleware,
            not_implemented_error_class=APINotImplementedError,
            content_mocked_header_name='X-Content-Mocked',
            default_list_size=10,
        )
        ```
    """
    logger.warning(self.warning_msg % self.__class__.__name__)
    self.app = app
    self.not_implemented_error_class = not_implemented_error_class
    self.content_mocked_header_name = content_mocked_header_name
    self.default_list_size = default_list_size

get_content async

get_content(scope, list_size=10)

Get generated content conforming to the route response model

Source code in fastapi_mock_middleware/middleware.py

async def get_content(self, scope, list_size: int = 10) -> Optional[dict]:
    """Get generated content conforming to the route response model"""
    route: APIRoute = scope['route']
    if not route.response_model:
        return None
    if route.response_model is Any:
        return {}

    content = None
    factory_class = self.get_mock_factory_class(route.response_model)
    if factory_class:
        factory = factory_class.create_factory(model=route.response_model, __use_defaults__=True)
        content = factory.build()
    elif isinstance(route.response_model, GenericAlias) and issubclass(get_origin(route.response_model), Sequence):
        # e.g. list[Model]
        item_type = get_args(route.response_model)[0]
        factory_class = self.get_mock_factory_class(item_type)
        if factory_class:
            factory = factory_class.create_factory(model=item_type, __use_defaults__=True)
            content = [factory.build() for _ in range(list_size)]
        else:
            content = BaseFactory.__faker__.pylist(list_size, value_types=[item_type], variable_nb_elements=False)
    elif isinstance(route.response_model, GenericAlias) and issubclass(get_origin(route.response_model), Mapping):
        # e.g. dict[str, Model]
        key_type, value_type = get_args(route.response_model)
        factory_class = self.get_mock_factory_class(value_type)
        if factory_class:
            factory = factory_class.create_factory(model=value_type, __use_defaults__=True)
            content = {
                key_type(): factory.build()
            }
        else:
            content = BaseFactory.__faker__.pydict(1, value_types=[value_type])
    else:
        provider = BaseFactory.get_provider_map().get(route.response_model, None)
        if provider:
            content = provider()
        else:
            raise ValueError(f'Cannot mock {route.response_model.__name__}')

    content = await serialize_response(
        field=route.response_field,
        response_content=content,
        include=route.response_model_include,
        exclude=route.response_model_exclude,
        by_alias=route.response_model_by_alias,
        exclude_unset=route.response_model_exclude_unset,
        exclude_defaults=route.response_model_exclude_defaults,
        exclude_none=route.response_model_exclude_none,
    )
    return content

fastapi_mock_middleware.APINotImplementedError

APINotImplementedError(*, return_value=None, list_size=None)

Bases: NotImplementedError

API NotImplementedError

Exception class to be risen on unimplemented endpoints for mocking their response data by MockAPIMiddleware

PARAMETER	DESCRIPTION
return_value	Value to return as mock data. Optional, in most cases autogenerated data should be enough. Use when specific data is required or in complex cases where data mocking according to response model did not work as expected. TYPE: Any DEFAULT: None
list_size	List size to generate for list responses. TYPE: int DEFAULT: None

Source code in fastapi_mock_middleware/middleware.py

def __init__(self, *, return_value: Any = None, list_size: int = None):
    """
    API NotImplementedError

    Exception class to be risen on unimplemented endpoints for mocking their
    response data by `MockAPIMiddleware`

    Args:
        return_value: Value to return as mock data. Optional, in most cases
            autogenerated data should be enough. Use when specific data
            is required or in complex cases where data mocking according to
            response model did not work as expected.
        list_size: List size to generate for list responses.
    """
    super().__init__()
    self.return_value = return_value
    self.list_size = list_size