Flask-Limiter for rate limiting - Mini Project: Build & Apply

Flask-Limiter for rate limiting

📖 Scenario: You are building a simple Flask web app that serves a greeting message. To protect your app from too many requests in a short time, you want to add rate limiting.This means users can only access the greeting a limited number of times per minute.

🎯 Goal: Build a Flask app with a single route /hello that returns a greeting message. Use Flask-Limiter to limit requests to 3 per minute per user IP.

📋 What You'll Learn

Create a Flask app instance named app

Set up Flask-Limiter with default limit of 3 requests per minute

Create a route /hello that returns 'Hello, world!'

Apply the rate limit to the /hello route

💡 Why This Matters

🌍 Real World

Rate limiting protects web apps from too many requests that can overload the server or cause abuse.

💼 Career

Understanding Flask-Limiter is useful for backend developers building secure and reliable Flask web applications.

1

Create the Flask app instance

Write code to import Flask from flask and create a Flask app instance called app.

Flask

# Import Flask and create app instance
# Your code here

Need a hint?

Use Flask(__name__) to create the app.

2

Set up Flask-Limiter with default limit

Import Limiter from flask_limiter and get_remote_address from flask_limiter.util. Create a Limiter instance named limiter with the app, key_func=get_remote_address, and set the default limit to 3 per minute using default_limits=["3 per minute"] to limit by user IP.

Flask

from flask import Flask
app = Flask(__name__)
# Import Limiter from flask_limiter and get_remote_address from flask_limiter.util, then create limiter with key_func=get_remote_address and default_limits=["3 per minute"]
# Your code here

Need a hint?

Use get_remote_address from flask_limiter.util for the IP key function.

3

Create the /hello route with rate limiting

Define a route /hello using @app.route('/hello'). Define a function hello() that returns the string 'Hello, world!'. Apply the rate limit decorator @limiter.limit('3 per minute') to this function.

Flask

from flask import Flask
from flask_limiter import Limiter
from flask_limiter.util import get_remote_address
app = Flask(__name__)
limiter = Limiter(app, key_func=get_remote_address, default_limits=["3 per minute"])

# Create /hello route with limiter.limit decorator
# Your code here

Need a hint?

Use both @app.route and @limiter.limit decorators above the function.

4

Add the app run block

Add the standard Flask app run block: if __name__ == '__main__': and inside it call app.run(debug=True) to start the server in debug mode.

Flask

from flask import Flask
from flask_limiter import Limiter
from flask_limiter.util import get_remote_address
app = Flask(__name__)
limiter = Limiter(app, key_func=get_remote_address, default_limits=["3 per minute"])

@app.route('/hello')
@limiter.limit('3 per minute')
def hello():
    return 'Hello, world!'

# Add app run block below
# Your code here

Need a hint?

This block runs the Flask app when you run the script directly.