Custom status codes in Flask - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to return a custom status code 202 in a Flask route.

Flask

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

@app.route('/')
def home():
    return jsonify(message='Accepted'), [1]

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

A200

B500

C404

D202

Attempts:

3 left

💡 Hint

Common Mistakes

Using 200 instead of 202

Using 404 which means Not Found

The status code 202 means the request has been accepted for processing.

2fill in blank

medium

Complete the code to define a Flask response with a custom status code 418 (I'm a teapot).

Flask

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

@app.route('/teapot')
def teapot():
    return Response('I am a teapot', status=[1])

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

A418

B404

C200

D500

Attempts:

3 left

💡 Hint

Common Mistakes

Using 200 instead of 418

Using 404 which means Not Found

Status code 418 is a playful HTTP code meaning "I'm a teapot".

3fill in blank

hard

Fix the error in the code to correctly return a JSON response with custom status code 429 (Too Many Requests).

Flask

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

@app.route('/limit')
def limit():
    return jsonify(error='Too many requests'), [1]

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

A200

B429

C404

D500

Attempts:

3 left

💡 Hint

Common Mistakes

Using 200 instead of 429

Using 404 which means Not Found

429 is the correct status code for "Too Many Requests".

4fill in blank

hard

Fill both blanks to create a Flask route that returns a JSON message with status code 451 (Unavailable For Legal Reasons).

Flask

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

@app.route('/legal')
def legal():
    return jsonify([1]='Unavailable for legal reasons'), [2]

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

Amessage

Berror

C451

D404

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'error' key instead of 'message'

Using 404 instead of 451

The key 'message' holds the text, and 451 is the status code for legal restrictions.

5fill in blank

hard

Fill all three blanks to return a Flask JSON response with a custom status code 207 (Multi-Status) and a custom key.

Flask

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

@app.route('/multi')
def multi():
    return jsonify([1]=[2]), [3]

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

Astatus

B'multi-status'

C207

D'error'

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'error' key instead of 'status'

Using 200 instead of 207

The JSON key is 'status' with value 'multi-status', and 207 is the custom status code.

Practice

1. What is the correct way to return a custom status code 450 from a Flask route?

easy

A. return "Error", 450

B. return 450, "Error"

C. return Response(status=450)

D. return make_response(450, "Error")

Solution

1. Step 1: Understand Flask return tuple format

   Flask routes return a tuple with (response_body, status_code) to set custom status codes.

2. Step 2: Match the tuple with custom code 450

   Returning "Error", 450 matches the format (body, status_code) correctly.

3. Final Answer:

   return "Error", 450 -> Option A

4. Quick Check:

   Tuple (body, status) = return "Error", 450 [OK]

Hint: Return (body, code) tuple to set custom status [OK]

Common Mistakes:

• Swapping order of status and body in return tuple
• Using Response without import or wrong parameters
• Using make_response incorrectly

2. Which of the following is the correct syntax to return a JSON response with a custom status code 499 in Flask?

easy

A. return jsonify(message="Fail"), 499

B. return jsonify(message="Fail", status=499)

C. return jsonify(message="Fail", 499)

D. return jsonify(message="Fail").status_code(499)

Solution

1. Step 1: Use jsonify to create JSON response

   jsonify returns a Response object with JSON content.

2. Step 2: Return tuple with jsonify and status code

   To set custom status code, return (jsonify(...), status_code) tuple.

3. Final Answer:

   return jsonify(message="Fail"), 499 -> Option A

4. Quick Check:

   jsonify + tuple (response, code) = return jsonify(message="Fail"), 499 [OK]

Hint: Return (jsonify(...), code) tuple for JSON + custom code [OK]

Common Mistakes:

• Passing status code inside jsonify arguments
• Trying to call status_code as method
• Incorrect tuple order or syntax

3. What will be the HTTP status code returned by this Flask route?

from flask import Flask
app = Flask(__name__)

@app.route('/test')
def test():
    return "Custom", 499

medium

A. 404

B. 200

C. 499

D. 500

Solution

1. Step 1: Check the return statement in route

   The route returns a tuple ("Custom", 499), where 499 is the status code.

2. Step 2: Flask uses the second tuple element as status code

   Flask sets HTTP status code to 499 as specified in the return tuple.

3. Final Answer:

   499 -> Option C

4. Quick Check:

   Return tuple second value = status code 499 [OK]

Hint: Second tuple value in return sets status code [OK]

Common Mistakes:

• Assuming default 200 status code
• Confusing return order
• Thinking 499 is invalid and defaults to 500

4. Identify the error in this Flask route that tries to return a custom status code 499:

from flask import Flask
app = Flask(__name__)

@app.route('/error')
def error():
    return "Oops", status=499

medium

A. Route function must return a Response object

B. Custom status code 499 is not allowed in Flask

C. Missing jsonify for JSON response

D. Using 'status' keyword argument in return is invalid

Solution

1. Step 1: Check return statement syntax

   Flask does not accept 'status' keyword in return statement directly.

2. Step 2: Correct way is to return tuple (body, status_code)

   Use return "Oops", 499 instead of return "Oops", status=499.

3. Final Answer:

   Using 'status' keyword argument in return is invalid -> Option D

4. Quick Check:

   Return tuple (body, code) not keyword args [OK]

Hint: Return tuple (body, code), not keyword args [OK]

Common Mistakes:

• Using status=code in return instead of tuple
• Assuming Flask auto-detects status from keywords
• Confusing with Response object parameters

5. You want to create a Flask route that returns a JSON message with a custom status code 460 only if a query parameter 'valid' is 'no'. Otherwise, return status 200 with a success message. Which code correctly implements this?

hard

A. from flask import Flask, request, jsonify
app = Flask(__name__)

@app.route('/check')
def check():
if request.args.get('valid') == 'no':
return jsonify(error="Invalid", status=460)
return jsonify(message="OK")

B. from flask import Flask, request, jsonify
app = Flask(__name__)

@app.route('/check')
def check():
if request.args.get('valid') == 'no':
return jsonify(error="Invalid"), 460
return jsonify(message="OK"), 200

C. from flask import Flask, request, jsonify
app = Flask(__name__)

@app.route('/check')
def check():
if request.args.get('valid') == 'no':
return jsonify(error="Invalid").status_code = 460
return jsonify(message="OK")

D. from flask import Flask, request, jsonify
app = Flask(__name__)

@app.route('/check')
def check():
if request.args.get('valid') == 'no':
return jsonify(error="Invalid")
return jsonify(message="OK"), 200

Solution

1. Step 1: Check conditional logic for query parameter

   Use request.args.get('valid') to check if it equals 'no'.

2. Step 2: Return JSON with custom status code 460 if invalid

   Return (jsonify(...), 460) tuple to set custom status code correctly.

3. Step 3: Return success JSON with status 200 otherwise

   Return (jsonify(...), 200) tuple for success response.

4. Final Answer:

   Correct conditional returns with tuples for custom and normal codes -> Option B

5. Quick Check:

   Return (jsonify, code) tuples for all cases [OK]

Hint: Return (jsonify(...), code) tuples for all responses [OK]

Common Mistakes:

• Passing status inside jsonify arguments
• Trying to set status_code attribute directly
• Missing status code tuple on error response