pip install marshmallow-sqlalchemy-referential
import sqlalchemy as sa
from sqlalchemy.ext.declarative import declarative_base
from marshmallow_sqlalchemy_referential import Referential
from marshmallow_sqlalchemy import ModelSchema
from marshmallow import fields
Base = declarative_base()
user_group_assoc = sa.Table(
'user_group_assoc', Base.metadata,
sa.Column('user_id', sa.Integer, sa.ForeignKey('user.id')),
sa.Column('group_id', sa.Integer, sa.ForeignKey('group.id'))
)
class User(Base):
__tablename__ = 'user'
id = sa.Column(sa.Integer(), primary_key=True)
groups = sa.orm.relationship('Group', secondary=user_group_assoc)
class Group(Base):
__tablename__ = 'group'
id = sa.Column(sa.Integer(), primary_key=True)
users = sa.orm.relationship('User', secondary=user_group_assoc)
class GroupSchema(ModelSchema):
class Meta():
dump_only = ['id']
id = fields.Integer()
class UserSchema(ModelSchema):
class Meta():
dump_only = ['id']
id = fields.Integer()
groups = Referential(GroupSchema, model=Group, many=True)