Subclassing Connection in 2.0

[nmrtv]

Hi, in 2.0dev version I can't see the way to subclass relay.Connection. Because SQLAlchemyObjectType doesn't have a Connection attribute, the only way I see is to pass connection via the Meta class. Otherwise the connection is automatically created with default Connection class. But I can't specify the subclassed connection in Meta, because it needs a node attribute and I get circular reference. E. g.

class UserConnection(graphene.relay.Connection):
    class Meta:
        node = User

class User(SQLAlchemyObjectType):
    class Meta:
        model = UserModel
        interfaces = (relay.Node, )
        connection = UserConnection

So I don't understand what's the point of connection parameter in SQLAlchemyObjectType Meta class? To make it work, I have changed SQLAlchemyObjectType.__init_subclass_with_meta__ and introduced connection_type parameter. Now I can make an abstract subclassed Connection and pass it to Meta:

class SQLAlchemyObjectType(ObjectType):
    @classmethod
    def __init_subclass_with_meta__(cls, model=None, registry=None, skip_registry=False,
                                    only_fields=(), exclude_fields=(), connection=None, connection_type=None,
                                    use_connection=None, interfaces=(), id=None, **options):

        ...

        if use_connection and not connection:
            # We create the connection automatically
            connection = (connection_type or Connection).create_type('{}Connection'.format(cls.__name__), node=cls) 

        ...

class UserConnection(graphene.relay.Connection):
    class Meta:
        abstract = True


class User(SQLAlchemyObjectType):
    class Meta:
        model = UserModel
        interfaces = (relay.Node, )
        connection_type = UserConnection

Maybe I don't understand something and there is an easier way to make it work?

[richmondwang]

I am also having trouble with this as I am adding custom specification for my connections.
This "feature" would be nice and (very) helpful to have.

---

For now, my workaround is to overwrite graphene.relay.Connection with my subclassed MyConnection.

import graphene.relay

class MyConnection(graphene.relay.Connection):
    class Meta:
        abstract = True


graphene.relay.Connection = MyConnection

[geertjanvdk]

@neriusmika Your fix is great and this is a fix that was done for the Django-version as well. Best would be to rename connection_type to connection_class.

[nikordaris]

I just submitted #120 which should fix this issue

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