JSON responses with jsonify in Flask - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the function that helps create JSON responses in Flask.

Flask

from flask import [1]

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

Arequest

Brender_template

CFlask

Djsonify

Attempts:

3 left

💡 Hint

Common Mistakes

Importing Flask instead of jsonify

Using render_template which is for HTML templates

Importing request which is for incoming data

The jsonify function is used to create JSON responses in Flask easily.

2fill in blank

medium

Complete the code to return a JSON response with a message using jsonify.

Flask

return [1]({'message': 'Hello, world!'})

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

Ajsonify

Brender_template

Cmake_response

Djson

Attempts:

3 left

💡 Hint

Common Mistakes

Using render_template which returns HTML

Using json which is a module, not a response function

Using make_response without jsonify

The jsonify function wraps the dictionary and returns a proper JSON response.

3fill in blank

hard

Fix the error in the code to correctly return a JSON response with a status code 201.

Flask

return jsonify({'status': 'created'}), [1]

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

A201

B200

C400

D500

Attempts:

3 left

💡 Hint

Common Mistakes

Using 200 which is generic success

Using 400 which means bad request

Using 500 which means server error

Status code 201 means the resource was created successfully and is the correct code here.

4fill in blank

hard

Fill both blanks to create a Flask route that returns a JSON response with a list of users.

Flask

@app.route('/users')
def get_users():
    users = ['Alice', 'Bob', 'Charlie']
    return [1]({'users': [2])

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

Ajsonify

Brender_template

Cusers

Drequest

Attempts:

3 left

💡 Hint

Common Mistakes

Using render_template which returns HTML

Passing 'request' instead of the users list

Not using jsonify for JSON response

The jsonify function is used to return JSON, and the users list is passed as the value.

5fill in blank

hard

Fill all three blanks to create a Flask route that accepts POST requests and returns a JSON response with the posted data.

Flask

@app.route('/submit', methods=[[1]])
def submit():
    data = [2].get_json()
    return [3]({'received': data})

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

A'POST'

Brequest

Cjsonify

D'GET'

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'GET' instead of 'POST' in methods

Using 'jsonify' as the request object

Not using jsonify to return JSON response

The route must accept 'POST' requests, use request.get_json() to get JSON data, and return it with jsonify.

Practice

1. What does the jsonify function in Flask do?

easy

A. Converts Python data to JSON and sets response headers correctly

B. Converts JSON data to Python objects

C. Creates HTML responses from Python dictionaries

D. Sends plain text responses without headers

Solution

1. Step 1: Understand the purpose of jsonify

   The jsonify function is designed to convert Python data structures like dictionaries or lists into JSON format.

2. Step 2: Recognize response headers setting

   It also automatically sets the HTTP response headers to indicate the content type is JSON, which is important for browsers or clients to understand the data format.

3. Final Answer:

   Converts Python data to JSON and sets response headers correctly -> Option A

4. Quick Check:

   jsonify converts data to JSON with headers [OK]

Hint: jsonify = Python data to JSON response with headers [OK]

Common Mistakes:

• Thinking jsonify converts JSON to Python
• Assuming jsonify creates HTML
• Ignoring response headers setup

2. Which of the following is the correct way to return a JSON response with jsonify in Flask?

easy

A. return jsonify('name', 'Alice', 'age', 30)

B. return json.dumps({'name': 'Alice', 'age': 30})

C. return jsonify({'name': 'Alice', 'age': 30})

D. return jsonify('name': 'Alice', 'age': 30)

Solution

1. Step 1: Check the syntax for jsonify with a dictionary

   The correct syntax is to pass a dictionary inside parentheses: jsonify({'key': value}).

2. Step 2: Identify the correct option

   return jsonify({'name': 'Alice', 'age': 30}) correctly uses a dictionary inside jsonify. return json.dumps({'name': 'Alice', 'age': 30}) uses json.dumps which returns a string, not a Flask response. return jsonify('name': 'Alice', 'age': 30) has incorrect syntax missing braces. return jsonify('name', 'Alice', 'age', 30) passes multiple positional arguments, causing a TypeError.

3. Final Answer:

   return jsonify({'name': 'Alice', 'age': 30}) -> Option C

4. Quick Check:

   jsonify expects a dict inside parentheses [OK]

Hint: Use jsonify with a dictionary inside parentheses [OK]

Common Mistakes:

• Using json.dumps instead of jsonify
• Passing key-value pairs without braces
• Passing multiple positional arguments to jsonify

3. What will be the output content type of this Flask route?

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

@app.route('/data')
def data():
    return jsonify({'success': True, 'count': 5})

medium

A. application/json

B. text/plain

C. text/html

D. application/xml

Solution

1. Step 1: Identify the response type from jsonify

   The jsonify function returns a Flask response with the content type set to application/json.

2. Step 2: Confirm the content type for JSON data

   Since the route returns jsonify({'success': True, 'count': 5}), the content type will be application/json.

3. Final Answer:

   application/json -> Option A

4. Quick Check:

   jsonify sets content type to application/json [OK]

Hint: jsonify always sets content type to application/json [OK]

Common Mistakes:

• Assuming default is text/html
• Confusing with plain text content type
• Thinking jsonify returns XML

4. Identify the error in this Flask route using jsonify:

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

@app.route('/info')
def info():
    data = {'name': 'Bob', 'age': 25}
    return jsonify(data['name'], data['age'])

medium

A. Route decorator syntax is wrong

B. Missing parentheses in jsonify call

C. Flask app not initialized correctly

D. jsonify expects a single dictionary or list, not multiple arguments

Solution

1. Step 1: Analyze the jsonify call arguments

   The code calls jsonify(data['name'], data['age']) passing two separate arguments instead of one dictionary or list.

2. Step 2: Understand jsonify argument requirements

   jsonify expects a single argument like a dictionary, list, or keyword arguments, not multiple positional arguments.

3. Final Answer:

   jsonify expects a single dictionary or list, not multiple arguments -> Option D

4. Quick Check:

   jsonify needs one dict/list argument [OK]

Hint: Pass one dict or list to jsonify, not multiple values [OK]

Common Mistakes:

• Passing multiple arguments to jsonify
• Confusing jsonify with print function
• Ignoring argument structure requirements

5. You want to return a JSON response with a list of users and a status message using jsonify. Which code correctly combines a list and a message in the JSON response?

hard

A. return jsonify(['Ann', 'Ben'], status='ok')

B. return jsonify({'users': ['Ann', 'Ben'], 'status': 'ok'})

C. return jsonify(users=['Ann', 'Ben'], 'status': 'ok')

D. return jsonify({'users': ['Ann', 'Ben']}, {'status': 'ok'})

Solution

1. Step 1: Understand how to combine data in jsonify

   To send multiple pieces of data, combine them into a single dictionary with keys and values.

2. Step 2: Evaluate each option

   return jsonify({'users': ['Ann', 'Ben'], 'status': 'ok'}) correctly creates one dictionary with keys 'users' and 'status'. return jsonify(['Ann', 'Ben'], status='ok') passes a list and a keyword argument, which is invalid. return jsonify(users=['Ann', 'Ben'], 'status': 'ok') mixes keyword arguments and dictionary syntax incorrectly. return jsonify({'users': ['Ann', 'Ben']}, {'status': 'ok'}) passes two dictionaries separately, which is not allowed.

3. Final Answer:

   return jsonify({'users': ['Ann', 'Ben'], 'status': 'ok'}) -> Option B

4. Quick Check:

   Combine all data in one dict for jsonify [OK]

Hint: Put all data in one dictionary before jsonify [OK]

Common Mistakes:

• Passing multiple arguments instead of one dict
• Mixing keyword args and dict syntax wrongly
• Trying to jsonify multiple separate dicts