Quick hack for json serialize/deserialize on a model with unsupported types, with pluggable interface

models.py

"""
This could probably be made a lot cleaner and add some more syntactic sugar that modifying the (de)serializers dicts on each object. First attempt
"""

class UtilModel(BaseModel):
    class Meta:
        abstract = True

    class_serializers = {
        UUID: lambda x: str(x),
        uuid.UUID: lambda x: str(x),
        DateTime: lambda x: x.isoformat()
    }

    class_deserializers = {
        uuid.UUID: lambda x: uuid.UUID(x),
        UUID: lambda x: UUID(x),
        DateTime: lambda x: DateTime(x)
    }

    serializers = {}
    deserializers = {}

    @classmethod
    def serialize(cls, name, obj):
        if name in cls.serializers:
            return cls.serializers[name](obj)

        return obj

    @classmethod
    def deserialize(cls, name, rep):
        if name in cls.deserializers:
            return cls.deserializers[name](rep)

        return rep

    def to_json(self):
        return json.dumps({
            column.model_name: self.serialize(column.model_name,
                                              getattr(self, column.model_name, None))
            for column in self.Meta.columns
        })

    @classmethod
    def from_json(cls, json_rep):
        json_des = {key: cls.deserialize(key, obj) for key, obj in json.loads(json_rep).items()}
        return cls(**json_des)


class Rotation(UtilModel):
    """
         This class represents a rotation, rotations get oncall reports
    """
    id = Column(UUID, hash_key=True)
    name = Column(String)
    pd = Column(String)

    serializers = {
        "id": UtilModel.class_serializers[UUID]
    }

still gotta test deserializing TBH

room to optimize around line 47

So, a RESTful API GET for a rotation looks like this:

@app.route('/apiv1/rotation/<uuid:rotation>', methods=["GET"]) #view
def get_rotation(rotation):
    return engine.query(Rotation, key=Rotation.id == rotation).one().to_json()

and the response is this:

 eflee@MacBook-Pro  ~  curl -vvv http://127.0.0.1:5000/apiv1/rotation/eda7073f-b274-4931-a34e-d817fd4adc9e
*   Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to 127.0.0.1 (127.0.0.1) port 5000 (#0)
> GET /apiv1/rotation/eda7073f-b274-4931-a34e-d817fd4adc9e HTTP/1.1
> Host: 127.0.0.1:5000
> User-Agent: curl/7.54.0
> Accept: */*
>
* HTTP 1.0, assume close after body
< HTTP/1.0 200 OK
< Content-Type: text/html; charset=utf-8
< Content-Length: 105
< Server: Werkzeug/0.12.2 Python/3.6.2
< Date: Fri, 04 Aug 2017 16:38:08 GMT
<
* Closing connection 0
{"id": "eda7073f-b274-4931-a34e-d817fd4adc9e", "pd": "http://linkity.linkerson", "name": "TestRotation1"}%

@app.route('/apiv1/rotation/<uuid:id>', methods=["PATCH"]) #update
def patch_rotation(id):
    data = request.get_json()
    try:
        rot = engine.query(Rotation, key=Rotation.id == id).one().to_dict()
        if "id" in data:
            assert data["id"]==str(id), "ID URI/Data mismatch"
        rot.update(data)
        engine.save(Rotation(**rot))
    except ConstraintViolation:
        # Rotation could not be found to patch
        abort(404, "Rotation could not be found")
    except AssertionError as e:
        abort(400, e)
    return Response(status=200)