HTTP methods (GET, POST, PUT, DELETE) in Flask - Mini Project: Build & Apply

HTTP methods (GET, POST, PUT, DELETE) with Flask

📖 Scenario: You are building a simple web service to manage a list of books. Each book has a unique ID and a title. You want to allow users to view all books, add a new book, update an existing book's title, and delete a book.

🎯 Goal: Create a Flask app that handles HTTP methods GET, POST, PUT, and DELETE to manage the books list.

📋 What You'll Learn

Create a dictionary called books with initial book entries

Add a variable called next_id to track the next book ID

Implement Flask routes to handle GET, POST, PUT, and DELETE methods

Use Flask's request object to get JSON data for POST and PUT

Return JSON responses with updated book data

💡 Why This Matters

🌍 Real World

Web services often need to handle different HTTP methods to create, read, update, and delete data. This project shows how to build such a service with Flask.

💼 Career

Understanding HTTP methods and how to implement them in web frameworks like Flask is essential for backend web development jobs.

1

DATA SETUP: Create initial books dictionary

Create a dictionary called books with these exact entries: 1: 'The Hobbit', 2: '1984', and 3: 'Pride and Prejudice'.

Flask

# Create the books dictionary with initial entries
# Your code here

Need a hint?

Use a Python dictionary with integer keys and string values.

2

CONFIGURATION: Add next_id variable

Add a variable called next_id and set it to 4 to track the next book ID.

Flask

books = {1: 'The Hobbit', 2: '1984', 3: 'Pride and Prejudice'}
# Add next_id variable
# Your code here

Need a hint?

This variable helps assign unique IDs to new books.

3

CORE LOGIC: Implement Flask routes for GET and POST

Import Flask and request from flask. Create a Flask app called app. Add a route /books that accepts GET and POST methods. For GET, return the books dictionary as JSON. For POST, get the title from JSON request data, add it to books with the current next_id, increment next_id, and return the new book entry as JSON.

Flask

books = {1: 'The Hobbit', 2: '1984', 3: 'Pride and Prejudice'}
next_id = 4

# Import Flask and request, create app
# Add /books route with GET and POST
# Your code here

Need a hint?

Use @app.route decorator and check request.method.

4

COMPLETION: Add routes for PUT and DELETE to update and delete books

Add a route /books/<int:book_id> that accepts PUT and DELETE methods. For PUT, get the title from JSON request data and update the book with book_id in books. For DELETE, remove the book with book_id from books. Return the updated or deleted book data as JSON.

Flask

from flask import Flask, request, jsonify

books = {1: 'The Hobbit', 2: '1984', 3: 'Pride and Prejudice'}
next_id = 4

app = Flask(__name__)

@app.route('/books', methods=['GET', 'POST'])
def books_route():
    global next_id
    if request.method == 'GET':
        return jsonify(books)
    elif request.method == 'POST':
        data = request.get_json()
        title = data.get('title')
        books[next_id] = title
        response = {next_id: title}
        next_id += 1
        return jsonify(response), 201

# Add /books/ route with PUT and DELETE
# Your code here

Need a hint?

Use route parameters and check request.method for PUT and DELETE.