如何在 python 中使用石墨烯-pydantic 和石墨烯的子类中的 pydantic 模型？

Question

Use Case Scenario

I've two pydantic models. Each in his own module (file). One Model, the TUser depends on the TAddress .

address_model.py

class TAddress(BaseModel):
    id: Optional[int]
    address: Optional[constr(max_length=100, strip_whitespace=True)]
    city: Optional[constr(max_length=80, strip_whitespace=True)]
    postal_code: Optional[constr(max_length=15, strip_whitespace=True)]
    country: Optional[constr(max_length=3)]

user_model.py

class TUser(BaseModel):
    id: UUID = None
    email: Optional[EmailStr]

    address: Optional[TAddress]

    is_active: Optional[bool]
    is_email_verified: Optional[bool]
    created_at: Optional[datetime.datetime]

If I use the TUser model know for my PydanticObjectType

class UserType(PydanticObjectType):
    class Meta:
        model = TUser

I get the following error message:

graphene_pydantic.converters.ConversionError: Don't know how to convert the Pydantic field ModelField(name='address', type=Optional[TAddress], required=False, default=None) (<class 'app.address.serializers.TAddress'>)

It seems like that there is a problem when using pydantic models from different modules that depends on each other. What is the solution for this use case?

Any idea?

Answer 1

The error message gives you the hint you need.

Don't know how to convert the Pydantic field ModelField(name='address'....

What's happening is that Graphene doesn't know how to convert the address class to be able to use it with the TUser because it is part of the PydanticObject .

In order to get rid of your error, you need to define a PydanticObjectType referring to TAddress , this way Graphene will know what is the relationship between these two objects.

In your schema file where you have the UserType just do this:

class AddressType(PydanticObjectType):
    class Meta:
        model = TAddress

class UserType(PydanticObjectType):
    class Meta:
        model = TUser