Avoiding verbs in URLs in Rest API - Time & Space Complexity

Time Complexity: Avoiding verbs in URLs

O(n)

Understanding Time Complexity

When designing REST APIs, the way URLs are structured affects how the server handles requests.

We want to understand how the choice of URL style impacts the number of operations the server performs.

Scenario Under Consideration

Analyze the time complexity of handling requests with URLs that avoid verbs.

GET /users/123
POST /users
PUT /users/123
DELETE /users/123
    

This code snippet shows typical REST API URLs using nouns and HTTP methods instead of verbs in the URL path.

Identify Repeating Operations

Look at what the server does when it receives these requests.

• Primary operation: Searching or updating user data by ID.
• How many times: Once per request, the server looks up the user or modifies data.

How Execution Grows With Input

The server work depends on how many users exist and how it finds them.

Input Size (n)	Approx. Operations
10 users	About 10 checks to find one user
100 users	About 100 checks
1000 users	About 1000 checks

Pattern observation: The time to find or update a user grows as the number of users grows.

Final Time Complexity

Time Complexity: O(n)

This means the server work grows linearly with the number of users when searching or updating.

Common Mistake

[X] Wrong: "Using verbs in URLs makes the server faster because it knows the action upfront."

[OK] Correct: The server still needs to find or update data; the URL style does not reduce the search or update work.

Interview Connect

Understanding how URL design affects server work helps you build clear and efficient APIs, a skill valued in many projects.

Self-Check

"What if the server used an index to find users instead of searching all? How would the time complexity change?"

Practice

1. Which of the following URLs follows the best practice of avoiding verbs in REST API design?

easy

A. /createUser

B. /getUser/123

C. /deleteUser/123

D. /users/123

Solution

1. Step 1: Understand URL naming conventions

   REST APIs should use nouns to represent resources, not verbs. URLs like /users/123 represent a user resource with ID 123.

2. Step 2: Identify verbs in URLs

   URLs like /getUser/123, /createUser, and /deleteUser/123 contain verbs (get, create, delete), which is against best practice.

3. Final Answer:

   /users/123 -> Option D

4. Quick Check:

   Use nouns in URLs = /users/123 [OK]

Hint: Use nouns for URLs, verbs go in HTTP methods [OK]

Common Mistakes:

• Including verbs like 'get' or 'delete' in the URL
• Using action words instead of resource names
• Confusing HTTP methods with URL paths

2. Which HTTP method should be used with the URL /orders/456 to update an existing order?

easy

A. PUT

B. POST

C. DELETE

D. GET

Solution

1. Step 1: Match HTTP methods to actions

   GET retrieves data, POST creates new data, PUT updates existing data, DELETE removes data.

2. Step 2: Identify update action

   To update an existing order at /orders/456, the correct HTTP method is PUT.

3. Final Answer:

   PUT -> Option A

4. Quick Check:

   Update = PUT [OK]

Hint: PUT updates, POST creates, GET reads, DELETE removes [OK]

Common Mistakes:

• Using POST to update instead of create
• Using GET to modify data
• Confusing PUT and DELETE methods

3. Given the REST API call: DELETE /products/789, what is the expected action?

medium

A. Delete product with ID 789

B. Create a new product with ID 789

C. Retrieve product with ID 789

D. Update product with ID 789

Solution

1. Step 1: Understand HTTP DELETE method

   DELETE is used to remove a resource identified by the URL.

2. Step 2: Apply to given URL

   The URL /products/789 identifies product 789, so DELETE removes it.

3. Final Answer:

   Delete product with ID 789 -> Option A

4. Quick Check:

   DELETE removes resource = Delete product with ID 789 [OK]

Hint: DELETE method removes resource at URL [OK]

Common Mistakes:

• Thinking DELETE retrieves data
• Confusing DELETE with POST or PUT
• Assuming URL contains action verbs

4. Identify the error in this REST API design: POST /updateUser/123

medium

A. User ID should not be in the URL

B. HTTP method POST cannot be used with user resources

C. URL contains a verb 'update', which should be avoided

D. URL should end with a question mark

Solution

1. Step 1: Check URL naming conventions

   URLs should use nouns to represent resources, not verbs like 'update'. The verb should be expressed by the HTTP method.

2. Step 2: Analyze the given URL

   The URL /updateUser/123 contains the verb 'update', which violates REST best practices.

3. Final Answer:

   URL contains a verb 'update', which should be avoided -> Option C

4. Quick Check:

   Verbs in URL = URL contains a verb 'update', which should be avoided [OK]

Hint: Avoid verbs in URLs; use HTTP methods for actions [OK]

Common Mistakes:

• Putting verbs like 'update' in URLs
• Misusing HTTP methods
• Ignoring resource identification in URLs

5. You want to design a REST API to manage blog posts. Which URL and HTTP method combination correctly avoids verbs in the URL and uses HTTP methods properly to delete a post with ID 321?

hard

A. DELETE /deletePost/321

B. DELETE /posts/321

C. POST /posts/321/delete

D. GET /posts/delete/321

Solution

1. Step 1: Identify correct URL structure

   The URL should use a noun representing the resource, here /posts/321, without verbs like 'delete'.

2. Step 2: Match HTTP method to action

   To delete a resource, use the DELETE method with the resource URL.

3. Final Answer:

   DELETE /posts/321 -> Option B

4. Quick Check:

   Delete resource = DELETE + noun URL [OK]

Hint: Use DELETE method with noun URL to remove resource [OK]

Common Mistakes:

• Including verbs like 'delete' in the URL
• Using GET or POST for delete actions
• Placing action words after resource ID