Practice/Netflix/Implement CRUD REST APIs

Implement CRUD REST APIs

CodingMust

Problem

You need to implement a simplified REST API handler that processes HTTP requests for managing user resources. Your system should support standard CRUD operations through appropriate HTTP methods and maintain an in-memory data store.

The API handler receives a sequence of operations, where each operation consists of an HTTP method, a path, and optional request data. You must process these operations in order and return the result of the final operation.

Your implementation should handle the following endpoints:

• POST /users - Create a new user with auto-incremented ID
• GET /users - Retrieve all users as an array
• GET /users/{id} - Retrieve a specific user by ID
• PUT /users/{id} - Update an existing user (merge with existing data)
• DELETE /users/{id} - Remove a user by ID

Requirements

1. Implement an in-memory storage system for user data
2. Auto-increment user IDs starting from 1
3. POST requests should create new users and return the created user object
4. GET requests should return individual users, all users, or null if not found
5. PUT requests should update existing user fields (partial updates allowed)
6. DELETE requests should remove users and return true on success
7. Return null when attempting to access non-existent resources
8. Process all operations sequentially and return the result of the last operation

Constraints

• Number of operations: 1 ≤ n ≤ 1000
• User IDs are positive integers
• User data contains at least "name" and "email" fields
• All inputs are valid (no malformed requests)
• Time complexity should be O(1) for individual operations
• Space complexity: O(n) where n is the number of users

Examples

Example 1:

Input: [ ("POST", "/users", {"name": "Alice", "email": "alice@example.com"}), ("GET", "/users/1", {}) ] Output: {"id": 1, "name": "Alice", "email": "alice@example.com"} Explanation: First operation creates a user with ID 1. Second operation retrieves that user, which is returned as the final result.

Example 2:

Input: [ ("POST", "/users", {"name": "Bob", "email": "bob@test.com"}), ("PUT", "/users/1", {"email": "bob.updated@test.com"}), ("GET", "/users/1", {}) ] Output: {"id": 1, "name": "Bob", "email": "bob.updated@test.com"} Explanation: Create user, update email field, then retrieve the updated user.

Example 3:

Input: [ ("POST", "/users", {"name": "Alice", "email": "alice@test.com"}), ("POST", "/users", {"name": "Bob", "email": "bob@test.com"}), ("GET", "/users", {}) ] Output: [{"id": 1, "name": "Alice", "email": "alice@test.com"}, {"id": 2, "name": "Bob", "email": "bob@test.com"}] Explanation: Create two users, then retrieve all users as an array.