Flask-Marshmallow AttributeError: List Object has no Attribute 'data'

Question

I have a local SQLlite DB which I have connected through the code below: '''

from flask import Flask, jsonify, request
from flask_sqlalchemy import SQLAlchemy
from sqlalchemy import Column, Integer, String, Float
import os
from flask_marshmallow import Marshmallow, Schema

app = Flask(__name__)
basedir = os.path.abspath(os.path.dirname(__file__))
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///' + os.path.join(basedir, 'planets.db')
db = SQLAlchemy(app)
ma = Marshmallow(app)


@app.cli.command('db_create')
def db_create():
    db.create_all()
    print('Database created!')


@app.cli.command('db_drop')
def db_drop():
    db.drop_all()
    print('Database dropped!')

@app.cli.command('db_seed')
def db_seed():
    mercury = Planet(planet_name='Mercury',
                     planet_type='Class D',
                     home_star='Sol',
                     mass=2.258e23,
                     radius=1516,
                     distance=35.98e6)

    venus = Planet(planet_name='Venus',
                         planet_type='Class K',
                         home_star='Sol',
                         mass=4.867e24,
                         radius=3760,
                         distance=67.24e6)

    earth = Planet(planet_name='Earth',
                     planet_type='Class M',
                     home_star='Sol',
                     mass=5.972e24,
                     radius=3959,
                     distance=92.96e6)

    db.session.add(mercury)
    db.session.add(venus)
    db.session.add(earth)

    test_user = User(first_name='William',
                     last_name='Herschel',
                     email='[email protected]',
                     password='P@ssw0rd')

    db.session.add(test_user)
    db.session.commit()
    print('Database seeded!')

@app.route('/planets', methods=['GET'])
def planets():
    planets_list = Planet.query.all()
    result = planets_schema.dump(planets_list)
    return jsonify(result.data)

# database models
class User(db.Model):
    __tablename__ = 'users'
    id = Column(Integer, primary_key=True)
    first_name = Column(String)
    last_name = Column(String)
    email = Column(String, unique=True)
    password = Column(String)
class Planet(db.Model):
    __tablename__ = 'planets'
    planet_id = Column(Integer, primary_key=True)
    planet_name = Column(String)
    planet_type = Column(String)
    home_star = Column(String)
    mass = Column(Float)
    radius = Column(Float)
    distance = Column(Float)

class UserSchema(ma.Schema):
    class Meta:
        fields = ('id', 'first_name', 'last_name', 'email', 'password')

class PlanetSchema(ma.Schema):
    class Meta:
        fields = ('planet_id', 'planet_name', 'planet_type', 'home_star', 'mass', 'radius', 'distance')

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

planet_schema = PlanetSchema()
planets_schema = PlanetSchema(many=True)


if __name__ == '__main__':
    app.run()
'''

I have tried passing return statement with return results[0] and it does work, but when i try to jsonify the same results, I am getting an error that it has no data.

I would love any inputs that help me solve this issue.

I have tried reinstalling the virtualenv and also all the packages, but I cannot understand why the .data doesnt seem to work. The other issues that I am facing which is truly not the issue, because all other aspects of the code are working including creating db, inserting records, and dropping tables. The query also seems to work since if I use the dict array to access the same. But the whole json string doesn't seem to work.

Answer 1

Remove .data from your code and simply write return jsonify(result). This would remove the Attribute Error.

Answer 2

You don't need to access .data attribute. Since the dump already returns the data. So try removing .dump and then try to run the application. It should give you the output that you are looking for.