Python Sql Alchemy - How to jsonify a class object result from a database query

You can use marshallow. Here is the example. define a serializer.py and put it beside your main.py file, and:

in serializer.py

from marshmallow import Serializer###### USER SERIALIZER #####class UserSerializer(Serializer):    class Meta:        # Fields to expose        fields = ('username')        # you can add any other member of class user in fields#Return the user data in json formatdef get_user_serialized(user):    return UserSerializer(user).data

in your main.py

from .serializers import get_user_serialized.........x = db.session.query(User).filter_by(username = request.form['username'], password = request.form['password']).first()serialized = [get_user_serialized(item) for item in x]res = jsonify(res=serialized)return res

With JSON serialize you can do that.

Look this: http://prschmid.blogspot.com/2012/12/json-serializing-sqlalchemy-objects.html

it work for me

I assume the variable '_updated' & '_created' in your class User are of type DateTime. Datetime is not serilzable in jsonify. You can just convert your datetime variable into str. i.e. str(some_date_in_datetimeformat) might work.
Also, '_sa_instance_state' which is of type sqlalchemy.orm.state.InstanceState should be serializable.

Update:

jsonify is not able to serialize your object. The best solution is to define a function serialize() inside your class and use it to make the data serializable. So your class becomes,

class User(object):    def serialize():        return {            '_id': 1,            'username': u'WashingtonGeorge'            'fullname': u'George Washington'            # other fields that you need in the json         }

then at the place where you want to jsonify the data, just call.

jsonify(x.serialize())