Dismiss type check during create_map

[CristhianMotoche]

Hello!

I've been looking for a library like this one and I think it can be pretty useful. I want to use it to convert an object that is mapped from a table of my database (I'm using Tortoise ORM for this):

from tortoise.models import Model
from tortoise import fields

class SessionTable(Model):
    __tablename__ = 'sessions'

    id = fields.IntField(pk=True)
    key = fields.CharField(max_length=8)

to a simple plain object that I use in my use cases (business logic):

@dataclass
class Session:
   id:int
   key:str

Then, my mapper should be something like:

mapper = ObjectMapper()
mapper.create_map(SessionTable, Session)
mapper.create_map(Session, SessionTable)
...
instance_session = mapper.map(session_table)
instance_sessiontable = mapper.map(session)

But, SessionTable isn't a type:

>>> type(SessionTable)
<class 'tortoise.models.ModelMeta'>

so, it fails with ObjectMapperException: type_from must be a type and ObjectMapperException: type_to must be a type during the map creation create_map.

Does it make sense to add a flag to avoid those asserts?

def create_map(self, type_from, type_to, mapping=None, allow_from_any = False, allow_to_any = False):
    ...
    if allow_from_any or (type(type_from) is not type):
       ...
    if allow_to_any or (type(type_to) is not type):
       ...

Although, I'm not sure if that would work since all data members need a default value. BTW, is it possible to solve that issue? If it is, I'd like to give it a try.

[asyncee]

I double this, faced same issue with pydantic and sqlalchemy. Is there are a change for this to be fixed?

[michaelwiles]

Yes Please! Same here

[leoalvs]

I faced this issue, solved using 1.0.7 version

[tylertjburns]

i changed the lines from:

         if type(type_from) is not type:
            raise ObjectMapperException("type_from must be a type")

         if type(type_to) is not type:
            raise ObjectMapperException("type_to must be a type")

to:

      if (not isinstance(type_from, type)):
            raise ObjectMapperException("type_from must be a type")

      if (not isinstance(type_to, type)):
          raise ObjectMapperException("type_to must be a type")

this worked well for me.