[REQ] Python-Flask - Python 3.7 util._deserialization

[nathan5280]

Is your feature request related to a problem? Please describe.

Unable to deserialize model objects when using Python 3.7.

When running with Python 3.7 openapi_server.util._deserialize fails because typing.GenericMeta was removed from 3.7.

Describe the solution you'd like

I'm not sure on where we are at with support for 3.7, but I worked on this fix and figured I should pass it along for when we get ready to support 3.7. Other than this I haven't found other issues.

Describe alternatives you've considered

Python 3.6

def _deserialize(data, klass):
    """Deserializes dict, list, str into an object.

    :param data: dict, list or str.
    :param klass: class literal, or string of class name.

    :return: object.
    """
    from cdst_places_app.openapi_server.models.base_model_ import Model

    if data is None:
        return None

    if klass in six.integer_types or klass in (float, str, bool):
        return _deserialize_primitive(data, klass)
    elif klass == object:
        return _deserialize_object(data)
    elif klass == datetime.date:
        return deserialize_date(data)
    elif klass == datetime.datetime:
        return deserialize_datetime(data)
    elif type(klass) == typing.GenericMeta:
        if klass.__extra__ == list:
            return _deserialize_list(data, klass.__args__[0])
        if klass.__extra__ == dict:
            return _deserialize_dict(data, klass.__args__[1])
    else:
        return deserialize_model(data, klass)

Python 3.7

import typing_inspect


def _deserialize(data, klass):
    """Deserializes dict, list, str into an object.

    :param data: dict, list or str.
    :param klass: class literal, or string of class name.

    :return: object.
    """
    from cdst_places_app.openapi_server.models.base_model_ import Model

    if data is None:
        return None

    if klass in six.integer_types or klass in (float, str, bool):
        return _deserialize_primitive(data, klass)
    elif klass == object:
        return _deserialize_object(data)
    elif klass == datetime.date:
        return deserialize_date(data)
    elif klass == datetime.datetime:
        return deserialize_datetime(data)
    elif typing_inspect.is_generic_type(klass):
        if typing_inspect.get_origin(klass) == list:
            return _deserialize_list(data, klass.__args__[0])
        if typing_inspect.get_origin(klass) == dict:
            return _deserialize_dict(data, klass.__args__[1])
    else:
        return deserialize_model(data, klass)

I'm not sure if the dict piece

        if typing_inspect.get_origin(klass) == dict:
            return _deserialize_dict(data, klass.__args__[1])

works or not. I don't have a spec that triggers this code.

Additional context

[spacether]

We have a test in the python swagger 2.0 spec which tests deserialization here:
https://github.com/OpenAPITools/openapi-generator/blob/master/samples/client/petstore/python/tests/test_deserialization.py
A similar test could be added to python-flask to verify solutions to this bug.

[cassinaooo]

Thanks for the hard work put in this tool!

I had the same problem with swagger-codegen and ended up migrating to openapi-codegen for unrelated reasons. My work around is on this issue swagger-api/swagger-codegen#8921, in case anyone is interested.

It does not depends on the typing_inspect, altough I am not sure that is relevant for every use case. However, my work around its not backwards compatible with python < 3.7.

[wing328]

#2884 has been merged into master

Please pull the latest master to give it a try.