Task: Add Input Validation to a Flask POST Endpoint

You are given a Flask route that accepts JSON to create a book record. It currently does no input validation. Your job is to add robust validation.

Starting Point

Create the file bookstore.py with the following content:

from flask import Flask, request, jsonify

app = Flask(__name__)

@app.route('/books', methods=['POST'])
def create_book():
    data = request.get_json()
    # TODO: add validation
    title = data['title']
    author = data['author']
    year = data['year']
    tags = data['tags']
    return jsonify({'title': title, 'author': author, 'year': year, 'tags': tags}), 201

if __name__ == '__main__':
    app.run()

Field Rules

Error Handling

When validation fails, the endpoint must return a JSON response with HTTP status 400. The response body must contain at least a "error" key with a human-readable message describing what went wrong.

When the request body is not valid JSON (or is absent), the endpoint must also return 400 with an appropriate error message.

Deliverables

• bookstore.py — updated with full input validation as described above.

Do not add a database, authentication, or any other features. Focus only on the validation logic.