Composite operations (multi-resource) in Rest API - Mini Project: Build & Apply

Composite Operations with Multiple Resources in REST API

📖 Scenario: You are building a simple REST API that manages a library system. The system has two resources: books and authors. Each book has a title and an author ID. Each author has a name.Sometimes, you want to perform multiple operations together, like adding a new author and then adding a book for that author in one go. This is called a composite operation.

🎯 Goal: Build a simple REST API that supports composite operations to create an author and a book together in one request.

📋 What You'll Learn

Create an in-memory data store for authors and books.

Add a configuration variable to track the next available ID for authors and books.

Implement a composite operation endpoint that creates an author and a book in one request.

Print the final state of authors and books after the composite operation.

💡 Why This Matters

🌍 Real World

Composite operations are common in real-world APIs where multiple related resources need to be created or updated together to keep data consistent.

💼 Career

Understanding composite operations helps in backend development, API design, and working with microservices where multiple resources interact.

1

DATA SETUP: Create in-memory data stores for authors and books

Create two empty dictionaries called authors and books to store authors and books respectively.

Rest API

# Create empty dictionaries for authors and books
# Your code here

Need a hint?

Use empty curly braces {} to create empty dictionaries.

2

CONFIGURATION: Add ID counters for authors and books

Create two variables called next_author_id and next_book_id and set both to 1 to track the next available IDs.

Rest API

authors = {}
books = {}
# Create ID counters for authors and books
# Your code here

Need a hint?

Use simple integer variables to keep track of IDs.

3

CORE LOGIC: Implement composite operation to add author and book

Write a function called add_author_and_book that takes author_name and book_title as parameters. Inside the function, use the global variables next_author_id and next_book_id. Add the author to authors with the next author ID, then add the book to books with the next book ID and link it to the author ID. Increment both ID counters by 1. Return a tuple with the new author ID and book ID.

Rest API

authors = {}
books = {}
next_author_id = 1
next_book_id = 1

def add_author_and_book(author_name, book_title):
    # Your code here

Need a hint?

Remember to use global to modify the ID counters inside the function.

4

OUTPUT: Call the composite operation and print authors and books

Call add_author_and_book with "Jane Austen" as author_name and "Pride and Prejudice" as book_title. Then print the authors and books dictionaries.

Rest API

authors = {}
books = {}
next_author_id = 1
next_book_id = 1

def add_author_and_book(author_name, book_title):
    global next_author_id, next_book_id
    author_id = next_author_id
    authors[author_id] = {'name': author_name}
    next_author_id += 1
    book_id = next_book_id
    books[book_id] = {'title': book_title, 'author_id': author_id}
    next_book_id += 1
    return author_id, book_id

# Call the function and print authors and books
# Your code here

Need a hint?

Call the function with the exact strings and then print both dictionaries.