How can I implement user authentication in Flask?

How can I implement user authentication in Flask?

You can use Flask-Login for user authentication. It helps manage user sessions and provides tools for login/logout.

What are the steps to set up Flask-Login?

First, install Flask-Login, then create a User model, set up login views, and configure the login manager.

Can you show me a code example?

Sure! Here's a simple example:

from flask import Flask, redirect, url_for, request
from flask_login import LoginManager, UserMixin, login_user, login_required, logout_user

app = Flask(__name__)
app.secret_key = 'your_secret_key'

login_manager = LoginManager()
login_manager.init_app(app)

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

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

@app.route('/login', methods=['GET', 'POST'])
def login():
    if request.method == 'POST':
        user = User(request.form['username'])
        login_user(user)
        return redirect(url_for('protected'))
    return 'Login Form'

@app.route('/protected')
@login_required
def protected():
    return 'Logged in successfully!'

@app.route('/logout')
@login_required
def logout():
    logout_user()
    return 'Logged out!'

This is a basic setup.

What about password hashing?

You should use a library like Werkzeug to hash passwords before storing them. Use generate_password_hash and check_password_hash for this.