serialchemy 0.20.0rc6.post13

Serializing Generic Types

Suppose we have an Employee SQLAlchemy model declared:

class Employee(Base):
    __tablename__ = 'Employee'

    id = Column(Integer, primary_key=True)
    fullname = Column(String)
    admission = Column(DateTime, default=datetime(2000, 1, 1))
    company_id = Column(ForeignKey('Company.id'))
    company = relationship(Company)
    company_name = column_property(
        select([Company.name]).where(Company.id == company_id)
    )
    password = Column(String)

Generic Types are automatically serialized by ModelSerializer:

from serialchemy import ModelSerializer

emp = Employee(fullname='Roberto Silva', admission=datetime(2019, 4, 2))

serializer = ModelSerializer(Employee)
serializer.dump(emp)

>> {'id': None,
    'fullname': 'Roberto Silva',
    'admission': '2019-04-02T00:00:00',
    'company_id': None,
    'company_name': None,
    'password': None
    }

New items can be deserialized by the same serializer:

new_employee = {'fullname': 'Jobson Gomes', 'admission': '2018-02-03'}
serializer.load(new_employee)
>> <Employee object at 0x000001C119DE3940>

Serializers do not commit into the database. You must do this by yourself:

emp = serializer.load(new_employee)
session.add(emp)
session.commit()

Custom Serializers

For anything beyond Generic Types we must extend the ModelSerializer class:

class EmployeeSerializer(ModelSerializer):

    password = Field(load_only=True)     # passwords should be only deserialized
    company = NestedModelField(Company)  # dump company as nested object

serializer = EmployeeSerializer(Employee)
serializer.dump(emp)

>> {'id': 1,
    'fullname': 'Roberto Silva',
    'admission': '2019-04-02T00:00:00',
    'company': {'id': 3,
                'name': 'Acme Co'
               }
    }