This Flask app lets users log in with a username and choose "Remember me". If checked, the user stays logged in after closing the browser. The protected page shows a greeting. Logout ends the session.
from flask import Flask, render_template_string, request, redirect, url_for
from flask_login import LoginManager, UserMixin, login_user, login_required, logout_user, current_user
app = Flask(__name__)
app.secret_key = 'secret-key'
login_manager = LoginManager()
login_manager.init_app(app)
# Simple user class
class User(UserMixin):
def __init__(self, id):
self.id = id
# User loader callback
@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'])
remember = 'remember' in request.form
login_user(user, remember=remember)
return redirect(url_for('protected'))
return render_template_string('''
<form method="post">
Username: <input type="text" name="username" required><br>
Remember me: <input type="checkbox" name="remember"><br>
<input type="submit" value="Login">
</form>
''')
@app.route('/protected')
@login_required
def protected():
return f'Hello, {current_user.id}! You are logged in.'
@app.route('/logout')
@login_required
def logout():
logout_user()
return 'You have been logged out.'
if __name__ == '__main__':
app.run(debug=False)
