How can I implement user authentication in Flask using SQLAlchemy?

How can I implement user authentication in Flask using SQLAlchemy?

You can implement user authentication in Flask using SQLAlchemy by creating a User model, setting up a registration form, and using Flask-Login for session management.

What does the User model look like?

The User model typically includes fields like id, username, email, and password_hash. You can define it like this:

class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(150), unique=True, nullable=False)
    email = db.Column(db.String(150), unique=True, nullable=False)
    password_hash = db.Column(db.String(128))

How do I hash passwords before storing them?

You can use the werkzeug.security module to hash passwords. Use generate_password_hash to hash the password and check_password_hash to verify it.

Can you show me how to set up Flask-Login?

Sure! First, install Flask-Login. Then, initialize it in your app and create a user loader function:

from flask_login import LoginManager

login_manager = LoginManager(app)

@login_manager.user_loader
def load_user(user_id):
    return User.query.get(int(user_id))