Safe methods vs unsafe methods in Rest API - Hands-On Comparison

Safe methods vs unsafe methods in REST API

📖 Scenario: You are building a simple REST API server that handles user data. Some HTTP methods are safe and do not change data, while others are unsafe and modify data.Understanding which methods are safe helps keep data secure and predictable.

🎯 Goal: Create a small program that stores user names and supports safe and unsafe HTTP methods. You will mark which methods are safe and which are unsafe.

📋 What You'll Learn

Create a dictionary called users with three users and their ages

Create a list called safe_methods containing the HTTP methods that do not change data

Create a list called unsafe_methods containing the HTTP methods that change data

Print the lists of safe and unsafe methods

💡 Why This Matters

🌍 Real World

Understanding safe and unsafe HTTP methods helps developers build APIs that protect data and behave predictably.

💼 Career

Many jobs in web development and backend programming require knowledge of REST API methods and their safety.

1

Create the initial user data

Create a dictionary called users with these exact entries: 'alice': 30, 'bob': 25, 'carol': 27

Rest API

# Create the users dictionary with exact entries
# Your code here

Hint

Use curly braces to create a dictionary with keys and values.

2

Define safe HTTP methods

Create a list called safe_methods containing these exact strings: 'GET', 'HEAD', 'OPTIONS'

Rest API

users = {'alice': 30, 'bob': 25, 'carol': 27}
# Create the safe_methods list with exact HTTP methods
# Your code here

Hint

Use square brackets to create a list of strings.

3

Define unsafe HTTP methods

Create a list called unsafe_methods containing these exact strings: 'POST', 'PUT', 'DELETE', 'PATCH'

Rest API

users = {'alice': 30, 'bob': 25, 'carol': 27}
safe_methods = ['GET', 'HEAD', 'OPTIONS']
# Create the unsafe_methods list with exact HTTP methods
# Your code here

Hint

Remember to use square brackets and quotes for list of strings.

4

Print the safe and unsafe methods

Write two print statements: one to print safe_methods and one to print unsafe_methods

Rest API

users = {'alice': 30, 'bob': 25, 'carol': 27}
safe_methods = ['GET', 'HEAD', 'OPTIONS']
unsafe_methods = ['POST', 'PUT', 'DELETE', 'PATCH']
# Print the safe_methods list
# Print the unsafe_methods list
# Your code here

Hint

Use print() to show the lists on the screen.

Practice

1. Which HTTP method is considered safe because it only retrieves data without changing anything?

easy

A. DELETE

B. POST

C. PUT

D. GET

Solution

1. Step 1: Understand safe methods

   Safe methods do not change data on the server; they only read or retrieve data.

2. Step 2: Identify the safe method among options

   GET is the method used to request data without modifying it, making it safe.

3. Final Answer:

   GET -> Option D

4. Quick Check:

   Safe method = GET [OK]

Hint: Safe methods only read data, GET is the common safe method [OK]

Common Mistakes:

• Confusing POST as safe
• Thinking PUT is safe
• Assuming DELETE is safe

2. Which of the following is the correct syntax to send data to a server to create a new resource?

easy

A. POST /resource HTTP/1.1

B. GET /resource HTTP/1.1

C. DELETE /resource HTTP/1.1

D. PUT /resource HTTP/1.1

Solution

1. Step 1: Identify method for creating resources

   POST is used to send data to the server to create new resources.

2. Step 2: Check syntax correctness

   POST /resource HTTP/1.1 is the correct syntax to send data for creation.

3. Final Answer:

   POST /resource HTTP/1.1 -> Option A

4. Quick Check:

   Creating resource = POST [OK]

Hint: POST is for sending data to create, syntax includes POST and resource path [OK]

Common Mistakes:

• Using GET to send data
• Confusing DELETE with POST
• Using PUT for creation without context

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

PUT /items/123 HTTP/1.1
Content-Type: application/json

{"name": "New Item"}

Choose the correct description.

medium

A. It retrieves the item with ID 123 without changes.

B. It updates or replaces the item with ID 123 with new data.

C. It deletes the item with ID 123 from the server.

D. It creates a new item without specifying an ID.

Solution

1. Step 1: Understand the PUT method purpose

   PUT is used to update or replace an existing resource at a specific URL.

2. Step 2: Analyze the request details

   The request targets /items/123 with JSON data, meaning it updates item 123.

3. Final Answer:

   It updates or replaces the item with ID 123 with new data. -> Option B

4. Quick Check:

   PUT updates resource = C [OK]

Hint: PUT replaces or updates resource at given URL [OK]

Common Mistakes:

• Thinking PUT retrieves data
• Confusing PUT with DELETE
• Assuming PUT creates without ID

4. Identify the error in this HTTP request if the goal is to safely retrieve data:

POST /users HTTP/1.1
Host: example.com

medium

A. The HTTP version is incorrect; it should be HTTP/2.0.

B. The Host header is missing, causing a syntax error.

C. POST is unsafe and changes data; GET should be used to retrieve data.

D. POST cannot be used with /users endpoint.

Solution

1. Step 1: Understand the goal and method used

   The goal is to safely retrieve data, but POST is used which changes data.

2. Step 2: Identify correct method for safe retrieval

   GET is the safe method to retrieve data without side effects.

3. Final Answer:

   POST is unsafe and changes data; GET should be used to retrieve data. -> Option C

4. Quick Check:

   Safe retrieval = GET, not POST [OK]

Hint: Use GET to retrieve data safely, not POST [OK]

Common Mistakes:

• Ignoring method safety
• Thinking Host header is missing
• Confusing HTTP versions

5. You want to design an API endpoint that allows clients to delete a user account safely. Which HTTP method should you use, and why?

hard

A. DELETE, because it explicitly removes the resource on the server.

B. POST, because it can send data and create resources.

C. GET, because it is safe and does not change data.

D. PUT, because it updates existing resources.

Solution

1. Step 1: Identify the action needed

   The goal is to remove (delete) a user account from the server.

2. Step 2: Choose the correct HTTP method for deletion

   DELETE is the method designed to remove resources safely and clearly.

3. Final Answer:

   DELETE, because it explicitly removes the resource on the server. -> Option A

4. Quick Check:

   Deleting resource = DELETE method [OK]

Hint: Use DELETE to remove resources explicitly and safely [OK]

Common Mistakes:

• Using GET for deletion
• Confusing POST with DELETE
• Using PUT instead of DELETE