database.py

#pip install sqlalchemy
#pip install flask-sqlalchemy
#from sqlalchemy import create_engine, Column, Integer, String
#from sqlalchemy.ext.declarative import declarative_base
#from sqlalchemy.orm import sessionmaker

from flask import Flask
from flask_sqlalchemy import SQLAlchemy

class SiteDatabase(object):
    UserObj = None
    db = None

    def configure_database_flask(self, app):
        global UserObj
        global db

        app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///:memory:'
        db = SQLAlchemy(app)

        class User(db.Model):
            id = db.Column(db.Integer, primary_key=True)
            username = db.Column(db.String(80), unique=True, nullable=False)
            email = db.Column(db.String(120), unique=True, nullable=False)
            password = db.Column(db.String(18), nullable=False)

            def __repr__(self):
                return '<User %r>' % self.username

        db.create_all()

        UserObj = User

    def create_user(self, username, email, password):
        return UserObj(username=username, email=email, password=password)

    def get_user(self, username):
        return UserObj.query.filter_by(username=username).first()

    def add_user(self, usr):
        db.session.add(usr)
        db.session.commit()