Flask Marshmallow

Serialization with Marshmallow

pip install flask-marshmallow marshmallow-sqlalchemy

from flask_marshmallow import Marshmallow

ma = Marshmallow(app)

class UserSchema(ma.SQLAlchemyAutoSchema):
    class Meta:
        model = User
        load_instance = True
        exclude = ("password",)

    email = ma.auto_field(validate=validate.Email())

user_schema  = UserSchema()
users_schema = UserSchema(many=True)

# Serialize
user_schema.dump(user)           # object → dict
users_schema.dump(users)

# Deserialize and validate
try:
    user = user_schema.load(request.json)  # dict → User object
except ValidationError as err:
    return jsonify(err.messages), 422

# In route
@api.route("/users/<int:id>")
def get_user(id):
    user = db.get_or_404(User, id)
    return jsonify(user_schema.dump(user))