HTTP status codes for APIs in Flask - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What HTTP status code does this Flask API return?

Consider this Flask route. What HTTP status code will the API respond with when accessed?

Flask

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

@app.route('/item/<int:id>')
def get_item(id):
    items = {1: 'apple', 2: 'banana'}
    if id in items:
        return jsonify({'item': items[id]}), 200
    else:
        return jsonify({'error': 'Item not found'}), 404

A 500 when item does not exist, 200 when item exists

B Always 200 regardless of item existence

C 200 when item exists, 404 when item does not exist

D 404 always, even if item exists

💡 Hint

Look at the return statements and the status codes they include.

The route returns 200 OK with the item data if the item exists. If the item ID is not found, it returns 404 Not Found with an error message.

📝 Syntax

intermediate

Identify the correct way to return a 201 Created status in Flask

Which option correctly returns a JSON response with HTTP status 201 Created after creating a resource?

Flask

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

@app.route('/create', methods=['POST'])
def create():
    new_item = {'id': 3, 'name': 'pear'}
    # Return response here

A return jsonify(new_item), 201

B return jsonify(new_item, 201)

C return jsonify(new_item).status_code(201)

D return new_item, 201

💡 Hint

Check the syntax for returning a tuple with response and status code.

In Flask, to return a JSON response with a specific status code, you return a tuple: (response, status_code). Option A correctly does this.

🔧 Debug

advanced

Why does this Flask route always return 200 OK even on error?

Examine this Flask route. Why does it always return HTTP 200 OK even when an error occurs?

Flask

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

@app.route('/divide/<int:a>/<int:b>')
def divide(a, b):
    try:
        result = a / b
        return jsonify({'result': result})
    except ZeroDivisionError:
        return jsonify({'error': 'Cannot divide by zero'})

A Because ZeroDivisionError is not caught properly

B Because no status code is specified, Flask defaults to 200 OK

C Because jsonify automatically sets status to 500 on errors

D Because the route method is missing @app.errorhandler decorator

💡 Hint

Think about what happens if you don't specify a status code in Flask.

Flask returns 200 OK by default if no status code is given. The error JSON is returned but with status 200, which is misleading.

❓ state_output

advanced

What is the HTTP status code after this Flask POST request?

Given this Flask route, what HTTP status code will the client receive after a successful POST request?

Flask

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

items = []

@app.route('/items', methods=['POST'])
def add_item():
    data = request.get_json()
    if not data or 'name' not in data:
        return jsonify({'error': 'Missing name'}), 400
    items.append(data['name'])
    return jsonify({'message': 'Item added'}), 201

A 200 OK

B 500 Internal Server Error

C 400 Bad Request

D 201 Created

💡 Hint

Check the return statement after adding the item.

The route returns 201 Created after successfully adding the item. It returns 400 if the 'name' is missing.

🧠 Conceptual

expert

Which HTTP status code best fits this API scenario?

You have an API endpoint that updates a user's profile. The update is successful but does not return any content. Which HTTP status code should the API return?

A 204 No Content

B 200 OK

C 201 Created

D 202 Accepted

💡 Hint

Think about status codes that indicate success but no response body.

204 No Content means the request was successful but there is no content to return. It's ideal for update operations that don't return data.