Cache management in GraphQL - Mini Project: Build & Apply

Cache Management with GraphQL

📖 Scenario: You are building a simple GraphQL API for a bookstore. To improve performance, you want to manage a cache of book data so that repeated requests for the same book do not always hit the database.

🎯 Goal: Create a basic cache management system using a dictionary to store book data keyed by book ID. You will set up the initial cache, configure a cache size limit, implement logic to add books to the cache, and finally complete the cache management by removing the oldest cached book when the cache exceeds the limit.

📋 What You'll Learn

Create a dictionary called cache with initial book entries.

Add a variable called cache_limit to set the maximum number of books in the cache.

Write a function called add_to_cache that adds a book to the cache and removes the oldest book if the cache size exceeds cache_limit.

Complete the cache management by updating the cache dictionary correctly when adding new books.

💡 Why This Matters

🌍 Real World

Cache management is important in APIs and databases to speed up data retrieval and reduce load on the main database.

💼 Career

Understanding cache management helps backend developers optimize application performance and scalability.

1

Set up the initial cache dictionary

Create a dictionary called cache with these exact entries: "book1": "GraphQL Basics", "book2": "Advanced GraphQL", and "book3": "GraphQL in Practice".

GraphQL

# Create the initial cache dictionary with three books
# Your code here

Need a hint?

Use curly braces {} to create a dictionary and add the three key-value pairs exactly as shown.

2

Add a cache size limit variable

Add a variable called cache_limit and set it to 3 to limit the cache size to three books.

GraphQL

cache = {
    "book1": "GraphQL Basics",
    "book2": "Advanced GraphQL",
    "book3": "GraphQL in Practice"
}
# Set the cache size limit
# Your code here

Need a hint?

Just create a variable named cache_limit and assign it the value 3.

3

Write the function to add books to the cache

Write a function called add_to_cache that takes book_id and book_title as parameters. It should add the book to the cache dictionary. If the cache size exceeds cache_limit, remove the oldest book (the first key in the dictionary).

GraphQL

cache = {
    "book1": "GraphQL Basics",
    "book2": "Advanced GraphQL",
    "book3": "GraphQL in Practice"
}
cache_limit = 3

# Define add_to_cache function
# Your code here

Need a hint?

Use len(cache) to check size and next(iter(cache)) to get the oldest key.

4

Complete the cache management by updating the cache

Call the add_to_cache function to add a new book with book_id "book4" and book_title "Mastering GraphQL". This will update the cache dictionary and remove the oldest book if needed.

GraphQL

cache = {
    "book1": "GraphQL Basics",
    "book2": "Advanced GraphQL",
    "book3": "GraphQL in Practice"
}
cache_limit = 3

def add_to_cache(book_id, book_title):
    cache[book_id] = book_title
    if len(cache) > cache_limit:
        oldest_key = next(iter(cache))
        del cache[oldest_key]

# Add a new book to the cache
# Your code here

Need a hint?

Call the function with the exact arguments to add the new book.