flask restless hybrid filtering

hybrid.py

import flask
import flask_sqlalchemy
import flask_restless
from sqlalchemy.ext.hybrid import hybrid_property
from sqlalchemy import event, select, func
from sqlalchemy.sql.expression import case

# Create the Flask application and the Flask-SQLAlchemy object.
app = flask.Flask(__name__)
app.config['DEBUG'] = True
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///test.db'
db = flask_sqlalchemy.SQLAlchemy(app)


class Workorder(db.Model):
    """
    A workorder assigned to crew that may have one or many features
    """
    __tablename__ = 'workorder'
    id = db.Column(db.Integer, primary_key=True,)
    features = db.relationship('Workorder_Feature', cascade='delete')

    @hybrid_property
    def is_complete(self):
        """
        when all features are completed, this workorder should be completed
        """
        features = Workorder_Feature.query.filter(Workorder_Feature.workorder_id == self.id)
        for f in features:
            if f.feature_status == 'Open':
                return 'No'
        return 'Yes'

    @is_complete.expression
    def is_complete(cls):
        return case({True: 'Yes', False: 'No'},
            select([func.count(Workorder_Feature.id)]).\
                where(Workorder_Feature.workorder_id==cls.id).\
                where(Workorder_Feature.feature_status == 'Open') == 0
        )


class Workorder_Feature(db.Model):
    """
    workorder features that are attached to a workorder. One workorder may have
    many workorder features
    """
    __tablename__ = 'workorder_feature'
    id = db.Column(db.Integer, primary_key=True,)
    workorder_id = db.Column( db.Integer(), db.ForeignKey('workorder.id'))
    feature_status = db.Column(db.String(25))
    workorder = db.relationship('Workorder')


# Create the database tables.
db.drop_all()
db.create_all()

for a in range(5):
    db.session.add(Workorder())
    db.session.commit()
    for a in range(5):
        db.session.add(Workorder_Feature(workorder_id=a, feature_status='Open'))

for a in range(5):
    db.session.add(Workorder())
    db.session.commit()
    for a in range(5):
        db.session.add(Workorder_Feature(workorder_id=a, feature_status='Closed'))

db.session.commit()


# Create the Flask-Restless API manager.
manager = flask_restless.APIManager(app, flask_sqlalchemy_db=db)

# Create API endpoints, which will be available at /api/<tablename> by
# default. Allowed HTTP methods can be specified as well.
manager.create_api(Workorder, methods=['GET', 'POST', 'DELETE'])
manager.create_api(Workorder_Feature, methods=['GET'])

if __name__ == '__main__':
    # start the flask loop
    app.run(host='0.0.0.0')