File download responses in Flask - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What does this Flask route return?

Consider this Flask route that sends a file to the user for download. What will the user experience when accessing this route?

Flask

from flask import Flask, send_file
app = Flask(__name__)

@app.route('/download')
def download():
    return send_file('example.txt', as_attachment=True)

A The browser will display the contents of 'example.txt' inline without download prompt.

B The browser will prompt the user to download 'example.txt' as a file.

C The server will return a 404 error because 'example.txt' is not found.

D The browser will show a blank page with no content.

💡 Hint

The 'as_attachment=True' argument controls how the file is sent to the browser.

Using send_file with as_attachment=True tells the browser to download the file instead of displaying it.

📝 Syntax

intermediate

Which option correctly sets a custom filename for download?

You want the user to download a file but with a different filename than the original. Which Flask code snippet correctly sets the download filename to 'report.pdf'?

Flask

from flask import send_file

# Assume 'data.pdf' exists on server

A return send_file('data.pdf', as_attachment=True, name='report.pdf')

B return send_file('data.pdf', as_attachment=True, filename='report.pdf')

C return send_file('data.pdf', as_attachment=True, download_name='report.pdf')

D return send_file('data.pdf', attachment_filename='report.pdf')

💡 Hint

Check the latest Flask parameter name for setting download filename.

In Flask 2.0+, download_name is the correct parameter to set the filename for download.

🔧 Debug

advanced

Why does this Flask file download route raise an error?

This route is intended to send a file for download but raises a TypeError. What is the cause?

Flask

from flask import send_file

@app.route('/getfile')
def getfile():
    return send_file('file.txt', as_attachment=True, download_name=123)

A as_attachment=True is invalid and causes a syntax error.

B Flask routes cannot return send_file directly.

C The file 'file.txt' does not exist, causing a FileNotFoundError.

D download_name must be a string, not an integer, causing a TypeError.

💡 Hint

Check the type of the download_name parameter.

The download_name parameter must be a string. Passing an integer causes a TypeError.

❓ state_output

advanced

What is the Content-Disposition header value sent by this Flask route?

Given this Flask route, what will be the exact Content-Disposition header value in the HTTP response?

Flask

from flask import send_file

@app.route('/dl')
def dl():
    return send_file('image.png', as_attachment=True, download_name='photo.png')

A attachment; filename=photo.png

B inline; filename=image.png

C attachment; filename=image.png

D inline; filename=photo.png

💡 Hint

as_attachment=True sets the disposition to attachment.

Using as_attachment=True sets Content-Disposition to attachment with the filename set to download_name.

🧠 Conceptual

expert

Why use send_file over send_from_directory for file downloads?

Which reason best explains why you might choose Flask's send_file instead of send_from_directory when sending a file for download?

A send_file allows sending any file-like object, not just files from a directory.

B send_from_directory automatically compresses files, send_file does not.

C send_from_directory requires the file to be in the root folder, send_file does not.

D send_file only works with static files, send_from_directory works with dynamic files.

💡 Hint

Think about flexibility in file sources.

send_file can send any file-like object, including in-memory files, while send_from_directory serves files only from a specific folder.