Why performance matters in Flask - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a basic Flask app that runs on the default port.

Flask

from flask import Flask
app = Flask(__name__)

@app.route('/')
def home():
    return 'Hello, World!'

if __name__ == '__main__':
    app.run([1])

Drag options to blanks, or click blank then click option'

Adebug=True

Bhost='0.0.0.0'

Cdebug=False

Dport=8080

Attempts:

3 left

💡 Hint

Common Mistakes

Using debug=True in production slows down the app and can expose sensitive info.

Setting debug=False runs the Flask app in normal mode, which is important for performance in production.

2fill in blank

medium

Complete the code to add caching to improve Flask app performance.

Flask

from flask import Flask
from flask_caching import Cache

app = Flask(__name__)
cache = Cache(app, config={'CACHE_TYPE': '[1]'})

@app.route('/')
@cache.cached(timeout=60)
def home():
    return 'Cached response!'

if __name__ == '__main__':
    app.run(debug=False)

Drag options to blanks, or click blank then click option'

Asimple

Bredis

Cfilesystem

Dnull

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing 'null' disables caching, so no performance benefit.

The simple cache type uses in-memory caching which is easy to set up and improves performance for small apps.

3fill in blank

hard

Fix the error in the code to correctly measure request processing time in Flask.

Flask

from flask import Flask, g, request
import time

app = Flask(__name__)

@app.before_request
def start_timer():
    g.start = time.time()

@app.after_request
def log_time(response):
    duration = time.time() - [1]
    print(f'Request took {duration:.4f} seconds')
    return response

@app.route('/')
def home():
    return 'Hello!'

if __name__ == '__main__':
    app.run(debug=False)

Drag options to blanks, or click blank then click option'

Astart

Bg.start

Ctime

Drequest.start

Attempts:

3 left

💡 Hint

Common Mistakes

Using a variable not defined in the current scope causes errors.

The start time is stored in g.start, so we must use that to calculate duration.

4fill in blank

hard

Fill both blanks to create a route that accepts a dynamic user ID and returns it.

Flask

from flask import Flask
app = Flask(__name__)

@app.route('/user/[1]')
def user_profile([2]):
    return f'User ID is {user_id}'

if __name__ == '__main__':
    app.run(debug=False)

Drag options to blanks, or click blank then click option'

A<int:user_id>

Buser_id

C<string:username>

Did

Attempts:

3 left

💡 Hint

Common Mistakes

Mismatching route parameter and function argument names causes errors.

The route uses <int:user_id> to capture an integer user ID, and the function parameter must match that name user_id.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps user IDs to their names for users with IDs greater than 10.

Flask

users = {1: 'Alice', 12: 'Bob', 15: 'Charlie', 7: 'Diana'}
filtered_users = { [1]: [2] for [3] in users if [1] > 10 }

Drag options to blanks, or click blank then click option'

Auser_id

Busers[user_id]

Duser

Attempts:

3 left

💡 Hint

Common Mistakes

Using a variable name not matching the dictionary keys causes errors.

The comprehension iterates over user_id in users, mapping user_id to users[user_id] for IDs greater than 10.