Session lifetime in Flask - Mini Project: Build & Apply

Managing Session Lifetime in Flask

📖 Scenario: You are building a simple Flask web app that tracks user visits using sessions. You want to control how long the session lasts before it expires automatically.

🎯 Goal: Create a Flask app that sets a session lifetime of 5 minutes and stores a visit count in the session. The app should increment the count on each visit and reset after the session expires.

📋 What You'll Learn

Create a Flask app with session support

Set the session lifetime to 5 minutes

Store a visit count in the session

Increment the visit count on each page load

Ensure the session expires after 5 minutes of inactivity

💡 Why This Matters

🌍 Real World

Web apps often need to remember user data temporarily, like login status or preferences. Managing session lifetime helps improve security and user experience by controlling how long this data stays active.

💼 Career

Understanding session management is essential for backend web developers working with Flask or similar frameworks to build secure and user-friendly applications.

1

Set up Flask app and secret key

Create a Flask app instance called app and set app.secret_key to the string 'mysecret'.

Flask

# Create Flask app and set secret key
# Your code here

Need a hint?

The secret key is needed to use sessions securely in Flask.

2

Configure session lifetime

Import timedelta from datetime and set app.permanent_session_lifetime to timedelta(minutes=5).

Flask

from flask import Flask
from datetime import timedelta

app = Flask(__name__)
app.secret_key = 'mysecret'
# Set session lifetime to 5 minutes
# Your code here

Need a hint?

Use timedelta to specify the session lifetime duration.

3

Create route to track visits with session

Import session and redirect, url_for from flask. Create a route / with a function index() that sets session.permanent = True, increments session['visits'] by 1 (initialize to 1 if not present), and returns the visit count as a string.

Flask

from flask import Flask, session, redirect, url_for
from datetime import timedelta

app = Flask(__name__)
app.secret_key = 'mysecret'
app.permanent_session_lifetime = timedelta(minutes=5)

@app.route('/')
def index():
    # Set session permanent
    # Increment visit count in session
    # Return visit count as string
    # Your code here

Need a hint?

Mark the session as permanent to apply the lifetime. Use session like a dictionary to store visit counts.

4

Run the Flask app

Add the code to run the Flask app with app.run(debug=True) inside the if __name__ == '__main__': block.

Flask

from flask import Flask, session, redirect, url_for
from datetime import timedelta

app = Flask(__name__)
app.secret_key = 'mysecret'
app.permanent_session_lifetime = timedelta(minutes=5)

@app.route('/')
def index():
    session.permanent = True
    if 'visits' in session:
        session['visits'] += 1
    else:
        session['visits'] = 1
    return f"Visit count: {session['visits']}"

# Add code to run the app
# Your code here

Need a hint?

This code starts the Flask server so you can test your app in a browser.