Why HTTP methods define intent in Rest API - See It in Action

Why HTTP Methods Define Intent

📖 Scenario: Imagine you are building a simple web service for a library. The library wants to manage its books online. Each action you take on the books, like adding a new book, checking details, updating information, or removing a book, needs to be clear and easy to understand by the web service.

🎯 Goal: You will create a small program that shows how different HTTP methods (GET, POST, PUT, DELETE) clearly express what you want to do with the books. This helps the web service know your intent and respond correctly.

📋 What You'll Learn

Create a dictionary called books with three books.

Create a variable called book_id set to 2.

Write code that uses the HTTP method GET to show the book details for book_id.

Print the result showing the HTTP method used and the book details.

💡 Why This Matters

🌍 Real World

Web services use HTTP methods to know what users want to do, like reading or changing data.

💼 Career

Knowing HTTP methods is essential for jobs in web development, API design, and backend programming.

1

DATA SETUP: Create the books dictionary

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

Rest API

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

Hint

Use curly braces {} to create a dictionary with keys 1, 2, 3 and their book titles as values.

2

CONFIGURATION: Set the book ID to access

Create a variable called book_id and set it to 2.

Rest API

books = {1: 'The Hobbit', 2: '1984', 3: 'Pride and Prejudice'}
# Set book_id to 2
# Your code here

Hint

Just assign the number 2 to the variable book_id.

3

CORE LOGIC: Use GET method to fetch book details

Write code that uses the HTTP method GET to get the book title from books using book_id. Store the result in a variable called result as a string in this format: 'GET book: [book title]'.

Rest API

books = {1: 'The Hobbit', 2: '1984', 3: 'Pride and Prejudice'}
book_id = 2
# Use GET method to get book title and store in result
# Your code here

Hint

Use an f-string to combine 'GET book: ' with the book title from the dictionary using book_id.

4

OUTPUT: Print the result

Write a print statement to display the value of result.

Rest API

books = {1: 'The Hobbit', 2: '1984', 3: 'Pride and Prejudice'}
book_id = 2
result = f"GET book: {books[book_id]}"
# Print the result
# Your code here

Hint

Use print(result) to show the output.

Practice

1. Which HTTP method is used to retrieve data from a server without changing it?

easy

A. GET

B. POST

C. DELETE

D. PUT

Solution

1. Step 1: Understand the purpose of HTTP methods

   GET is designed to request data without modifying it, making it safe and idempotent.

2. Step 2: Match method to action

   Since the question asks for retrieving data without changes, GET fits perfectly.

3. Final Answer:

   GET -> Option A

4. Quick Check:

   Retrieve data = GET [OK]

Hint: GET is for reading data, no changes made [OK]

Common Mistakes:

• Confusing GET with POST
• Thinking DELETE retrieves data
• Using PUT to fetch data

2. Which of the following is the correct syntax to update a resource using HTTP methods?

easy

A. GET /resource/123

B. DELETE /resource/123

C. POST /resource/123

D. PUT /resource/123

Solution

1. Step 1: Identify the method used for updating

   PUT is the HTTP method used to update or replace a resource at a specific URL.

2. Step 2: Check the syntax correctness

   PUT /resource/123 correctly targets the resource with ID 123 for update.

3. Final Answer:

   PUT /resource/123 -> Option D

4. Quick Check:

   Update resource = PUT [OK]

Hint: PUT updates existing resources fully [OK]

Common Mistakes:

• Using GET to update
• POST is for creating, not updating
• DELETE removes, not updates

3. What will be the expected result of this HTTP request?

POST /users
{
  "name": "Alice",
  "age": 30
}

medium

A. Create a new user named Alice

B. Delete user Alice

C. Update existing user Alice's age

D. Retrieve user data for Alice

Solution

1. Step 1: Identify the HTTP method used

   POST is used to create new resources on the server.

2. Step 2: Analyze the request body

   The JSON data contains user details, indicating creation of a new user named Alice.

3. Final Answer:

   Create a new user named Alice -> Option A

4. Quick Check:

   POST with data = Create new resource [OK]

Hint: POST adds new data, not fetch or delete [OK]

Common Mistakes:

• Thinking POST retrieves data
• Confusing POST with PUT for update
• Assuming POST deletes data

4. You want to remove a user with ID 45 using an HTTP request, but the request POST /users/45 is not working. What is the correct method to use?

medium

A. GET

B. PUT

C. DELETE

D. PATCH

Solution

1. Step 1: Understand the intent of the request

   The goal is to remove (delete) a user, so the method must express deletion.

2. Step 2: Choose the HTTP method for deletion

   DELETE is the standard method to remove a resource identified by a URL.

3. Final Answer:

   DELETE -> Option C

4. Quick Check:

   Remove resource = DELETE [OK]

Hint: DELETE removes resources, POST does not [OK]

Common Mistakes:

• Using POST to delete
• Confusing PATCH with DELETE
• Trying GET to remove data

5. You have an API where PATCH /profile/123 updates only the email field of a user profile, while PUT /profile/123 replaces the entire profile. Why is it important to choose PATCH over PUT when updating just one field?

hard

A. PATCH is faster because it sends less data

B. PUT can accidentally erase other fields if not included

C. PATCH creates a new profile instead of updating

D. PUT is only for deleting resources

Solution

1. Step 1: Understand the difference between PUT and PATCH

   PUT replaces the entire resource, so missing fields get erased. PATCH updates only specified fields.

2. Step 2: Analyze the risk of using PUT for partial updates

   If you use PUT but omit some fields, those fields may be removed unintentionally.

3. Final Answer:

   PUT can accidentally erase other fields if not included -> Option B

4. Quick Check:

   Partial update safe = PATCH, full replace risk = PUT [OK]

Hint: Use PATCH for partial updates to avoid data loss [OK]

Common Mistakes:

• Thinking PATCH creates new resource
• Believing PUT only deletes
• Assuming PATCH sends no data