How to create a User class for Flask-Login when using dynamodb?

Question

I am following the tutorial at https://www.digitalocean.com/community/tutorials/how-to-add-authentication-to-your-app-with-flask-login for adding register/login features to a flask app, which uses Flask-Login with an SQLite database (using flask_sqlalchemy). As such, it has code like the following for initializing the SQLite database (from init.py):

db = SQLAlchemy()
def create_app():
    app = Flask(__name__)

    app.config['SECRET_KEY'] = '9OLWxND4o83j4K4iuopO'
    app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///db.sqlite'

    db.init_app(app)

And then creates a User class (as is required by Flask-Login) like this:

from flask_login import UserMixin
from . import db

class User(UserMixin, db.Model):
    id = db.Column(db.Integer, primary_key=True) # primary keys are required by SQLAlchemy
    email = db.Column(db.String(100), unique=True)
    password = db.Column(db.String(100))
    name = db.Column(db.String(1000))

However, I want to store user information in a dynamodb table, not a SQLite table. How then should I write the User class? I want each User to have an email, password and name property like in this tutorial (along with other properties/methods required at https://flask-login.readthedocs.io/en/latest/#your-user-class as is handled by UserMixin), but am unsure how to write the class when using dynamodb.

Asked By: ZhouW

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Source

Answer 1

I wrote the User class simply as follows:

class User(UserMixin):
    def __init__(self, id, email, name, password):
        self.id = id
        self.email = email
        self.name = name
        self.password = password

Answered By: ZhouW

Answer 2

I used the User class from ZhouW and you will also need a custom user_loader. This here should work:

class User(UserMixin):
    def __init__(self, id, email, password):
        self.id = id
        self.email = email
        self.password = password

@login_manager.user_loader
def loader(user_id):
    response = table.query(
            KeyConditionExpression=Key('id').eq(user_id))
    
    if response["Count"] == 0:
        return
    user = User(id=response['Items'][0]["id"], email=response['Items'][0]["email"], password=response['Items'][0]["password"])
    return user

Will need a table first, connect something like this:

dynamodb = boto3.resource('dynamodb')
table = dynamodb.Table('users')
from boto3.dynamodb.conditions import Key

Answered By: Jonan

How to create a User class for Flask-Login when using dynamodb?

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