Redirect and abort functions in Flask - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What happens when this Flask route is accessed?

Consider this Flask route:

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

@app.route('/go')
def go():
    return redirect('/target')

What will the browser do when a user visits /go?

Flask

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

@app.route('/go')
def go():
    return redirect('/target')

A The browser will show a 404 error because '/target' route is not defined.

B The browser will be redirected to the URL '/target' with a 302 status code.

C The server will return a JSON response with the URL '/target'.

D The browser will stay on '/go' and display a blank page.

💡 Hint

Think about what the redirect function does in Flask.

The redirect function sends a 302 HTTP response telling the browser to load the new URL '/target'. It does not require the '/target' route to be defined for the redirect to happen.

📝 Syntax

intermediate

Which option correctly aborts with a 404 error in Flask?

You want to stop processing and return a 404 Not Found error in a Flask route. Which code snippet does this correctly?

Flask

from flask import abort

@app.route('/item/<int:id>')
def item(id):
    if id != 1:
        # abort here
    return 'Item found'

A abort(404)

B abort(404, 'Not Found')

C abort('404')

D abort(400)

💡 Hint

The abort function expects an integer status code.

abort(404) correctly raises a 404 HTTP error. Passing a string or a different status code will either cause an error or return a different HTTP status.

❓ state_output

advanced

What is the HTTP status code returned by this route?

Analyze this Flask route:

from flask import Flask, abort, redirect
app = Flask(__name__)

@app.route('/check')
def check():
    if False:
        return redirect('/success')
    else:
        abort(403)

What HTTP status code will the client receive when accessing '/check'?

Flask

from flask import Flask, abort, redirect
app = Flask(__name__)

@app.route('/check')
def check():
    if False:
        return redirect('/success')
    else:
        abort(403)

A 404 Not Found

B 302 Found

C 403 Forbidden

D 200 OK

💡 Hint

Look at the condition and which branch runs.

Since the condition is always False, the else branch runs, calling abort(403), which returns a 403 Forbidden HTTP status code.

🔧 Debug

advanced

Why does this Flask code raise an error?

Look at this Flask route:

from flask import abort

@app.route('/data')
def data():
    abort('404')

What error will this code cause and why?

Flask

from flask import abort

@app.route('/data')
def data():
    abort('404')

A No error; it returns a 404 error correctly.

B SyntaxError due to missing parentheses in abort call.

C RuntimeError because abort cannot be called inside a route.

D TypeError because abort expects an integer status code, not a string.

💡 Hint

Check the type of the argument passed to abort.

abort expects an integer HTTP status code. Passing a string like '404' causes a TypeError.

🧠 Conceptual

expert

What is the difference between redirect and abort in Flask?

Choose the best explanation of how redirect and abort functions behave in Flask.

A redirect sends a response telling the browser to visit a new URL; abort stops processing and returns an HTTP error code.

B redirect stops the server and returns an error; abort sends the browser to a new URL.

C Both redirect and abort send the browser to a new URL but with different status codes.

D redirect and abort are interchangeable and both return HTTP 404 errors.

💡 Hint

Think about what happens to the browser in each case.

redirect tells the browser to load a different URL (usually with 302 status). abort stops the request and returns an HTTP error code like 404 or 403.