Flask-Compress for compression - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What output does this Flask app produce with Flask-Compress?

Consider this Flask app using Flask-Compress. What will the client receive when requesting the '/' route with 'Accept-Encoding: gzip'?

Flask

from flask import Flask
from flask_compress import Compress

app = Flask(__name__)
Compress(app)

@app.route('/')
def index():
    return 'Hello, compressed world!'

# Client sends header: Accept-Encoding: gzip

A The response body is compressed with gzip encoding.

B The response body is compressed but with Brotli encoding.

C The server returns a 404 error because the route is missing.

D The response body is sent uncompressed because Flask-Compress is not enabled.

💡 Hint

Flask-Compress automatically compresses responses if the client supports it.

Flask-Compress detects the 'Accept-Encoding' header and compresses the response accordingly. Since the client requests gzip, the response is gzip compressed.

📝 Syntax

intermediate

Which option correctly initializes Flask-Compress in this app?

Given a Flask app instance app, which code snippet correctly enables Flask-Compress?

Flask

from flask import Flask
from flask_compress import Compress

app = Flask(__name__)
# Which line correctly enables compression?

A Compress(app)

B app = Compress(app)

C Compress().init_app(app)

D app.compress = Compress(app)

💡 Hint

Flask-Compress can be initialized by passing the app instance directly.

The simplest way is to create a Compress instance with the app as argument: Compress(app).

🔧 Debug

advanced

Why does Flask-Compress not compress this JSON response?

In this Flask app, the JSON response is not compressed even though Flask-Compress is enabled. Why?

Flask

from flask import Flask, jsonify
from flask_compress import Compress

app = Flask(__name__)
Compress(app)

@app.route('/data')
def data():
    response = jsonify({'key': 'value'})
    response.headers['Content-Encoding'] = 'identity'
    return response

A Because Flask-Compress does not support JSON responses.

B Because the response header 'Content-Encoding' is manually set to 'identity', preventing compression.

C Because the route function returns a dictionary instead of a response object.

D Because Flask-Compress requires the response to be a string, not JSON.

💡 Hint

Check if any headers might block compression.

Manually setting 'Content-Encoding' to 'identity' tells Flask-Compress not to compress the response. Flask-Compress respects this header and skips compression.

❓ state_output

advanced

What is the effect of setting COMPRESS_LEVEL to 9 in Flask-Compress?

In Flask-Compress configuration, what does setting app.config['COMPRESS_LEVEL'] = 9 do?

Flask

from flask import Flask
from flask_compress import Compress

app = Flask(__name__)
app.config['COMPRESS_LEVEL'] = 9
Compress(app)

A It sets the compression to the lowest level, making compression faster but less effective.

B It disables compression entirely.

C It causes a runtime error because 9 is an invalid compression level.

D It sets the gzip compression to the highest level, increasing compression but using more CPU.

💡 Hint

Compression levels usually range from 1 to 9.

Compression level 9 means maximum compression, which uses more CPU time but reduces response size more.

🧠 Conceptual

expert

Which header must the client send to receive compressed responses from Flask-Compress?

To get compressed responses from a Flask app using Flask-Compress, which HTTP header should the client include?

A Cache-Control: no-cache

B Content-Type: application/json

C Accept-Encoding: gzip, deflate, br

D Content-Encoding: gzip

💡 Hint

Think about how clients tell servers what compression they support.

The client sends 'Accept-Encoding' to tell the server which compression methods it supports. Flask-Compress uses this to decide whether to compress the response.