Resource-based design thinking in Rest API - Step-by-Step Execution

Concept Flow - Resource-based design thinking

Identify Resources

↓

Define Resource URIs

↓

Design HTTP Methods

↓

Specify Representations

↓

Implement Stateless Interactions

↓

Test and Iterate

This flow shows how to design a REST API by focusing on resources, their URIs, HTTP methods, and representations.

Execution Sample

Rest API

GET /books/123 HTTP/1.1
Host: example.com

Response:
200 OK
{
  "id": 123, "title": "REST Basics"
}

This example shows a client requesting a book resource by its ID and receiving its details.

Execution Table

Step	Action	Request/Response	Resource URI	HTTP Method	Result
1	Client requests a resource	GET /books/123	/books/123	GET	Server receives request
2	Server locates resource	N/A	/books/123	GET	Resource found in database
3	Server prepares response	N/A	/books/123	GET	Resource data serialized as JSON
4	Server sends response	200 OK with JSON body	/books/123	GET	Client receives resource data
5	Client processes data	N/A	/books/123	GET	Data displayed or used in app
6	Client sends update	PUT /books/123 with JSON body	/books/123	PUT	Server updates resource
7	Server confirms update	200 OK	/books/123	PUT	Resource updated successfully
8	Client deletes resource	DELETE /books/123	/books/123	DELETE	Server deletes resource
9	Server confirms deletion	204 No Content	/books/123	DELETE	Resource removed
10	Client requests deleted resource	GET /books/123	/books/123	GET	404 Not Found
11	End	N/A	N/A	N/A	Resource lifecycle complete

💡 Resource lifecycle ends when client receives 404 after deletion.

Variable Tracker

Variable	Start	After Step 2	After Step 3	After Step 6	After Step 8	Final
Resource Exists	False	True	True	True	False	False
Resource Data	None	{"id":123,"title":"REST Basics"}	{"id":123,"title":"REST Basics"}	{"id":123,"title":"Updated Title"}	None	None
Response Status	None	None	200 OK	200 OK	204 No Content	404 Not Found

Key Moments - 3 Insights

Why does the client get a 404 Not Found after deleting the resource?

After step 8, the resource is deleted on the server, so when the client requests it again at step 10, the server cannot find it and returns 404 as shown in the execution_table.

What HTTP method is used to update a resource and why?

The PUT method is used to update a resource as shown in step 6 because it replaces the resource at the given URI with the new data.

Why must the server be stateless in resource-based design?

The server treats each request independently without storing client state, ensuring scalability and simplicity, as implied in the concept_flow step 'Implement Stateless Interactions'.

Visual Quiz - 3 Questions

Look at the execution_table, what is the HTTP method used at step 6?

A PUT

B GET

C POST

D DELETE

💡 Hint

Check the 'HTTP Method' column at step 6 in the execution_table.

At which step does the resource get deleted from the server?

A Step 4

B Step 8

C Step 10

D Step 2

💡 Hint

Look for the DELETE method action in the execution_table.

If the client tries to GET the resource after deletion, what response status will it receive?

A 200 OK

B 204 No Content

C 404 Not Found

D 500 Internal Server Error

💡 Hint

See the response status at step 10 in the execution_table.

Concept Snapshot

Resource-based design thinking focuses on modeling APIs around resources.
Each resource has a unique URI.
Use HTTP methods (GET, PUT, DELETE) to interact.
Server responses include resource representations.
Server is stateless; each request is independent.

Full Transcript

Resource-based design thinking is a way to build REST APIs by focusing on resources. Each resource has a unique address called a URI. Clients use HTTP methods like GET to read, PUT to update, and DELETE to remove resources. The server sends back data in formats like JSON. The server does not remember past requests, making it stateless. This approach helps create clear, scalable APIs. The execution table shows a client requesting a book resource, updating it, deleting it, and then trying to get it again, receiving a 404 error because it no longer exists.

Practice

1. What is the main idea behind resource-based design thinking in REST APIs?

easy

A. Focusing only on database tables

B. Using only POST requests for all actions

C. Designing APIs without any structure

D. Organizing APIs around things like users or products

Solution

1. Step 1: Understand the concept of resource-based design

   Resource-based design means APIs are built around resources, which are things like users, products, or orders.

2. Step 2: Compare options to the concept

   Only Organizing APIs around things like users or products correctly describes organizing APIs around things (resources). Other options describe incorrect or unrelated ideas.

3. Final Answer:

   Organizing APIs around things like users or products -> Option D

4. Quick Check:

   Resource-based design = Organizing APIs around resources [OK]

Hint: Think of APIs as managing 'things' like users or products [OK]

Common Mistakes:

• Confusing resource-based design with database design
• Thinking all requests must be POST
• Ignoring the concept of resources

2. Which HTTP method is typically used to update an existing resource in a REST API?

easy

A. PUT

B. POST

C. GET

D. DELETE

Solution

1. Step 1: Recall HTTP methods and their common uses

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

2. Step 2: Identify the method for updating

   PUT is the standard method used to update an existing resource in REST APIs.

3. Final Answer:

   PUT -> Option A

4. Quick Check:

   Update resource = PUT [OK]

Hint: PUT means replace or update a resource fully [OK]

Common Mistakes:

• Using POST to update instead of create
• Confusing GET with update
• Using DELETE for updating

3. Given this REST API call: DELETE /products/123, what is the expected result?

medium

A. Retrieve product with ID 123

B. Create a new product with ID 123

C. Delete product with ID 123

D. Update product with ID 123

Solution

1. Step 1: Analyze the HTTP method and URL

   DELETE method means remove. The URL targets the product resource with ID 123.

2. Step 2: Determine the action

   DELETE /products/123 means delete the product with ID 123 from the system.

3. Final Answer:

   Delete product with ID 123 -> Option C

4. Quick Check:

   DELETE + resource ID = delete that resource [OK]

Hint: DELETE + resource ID means remove that resource [OK]

Common Mistakes:

• Thinking DELETE retrieves data
• Confusing DELETE with POST or PUT
• Ignoring the resource ID in URL

4. You see this API request: POST /users/45. What is wrong with this request in resource-based design?

medium

A. The URL should be /users without ID for creating

B. POST cannot be used to create resources

C. The HTTP method should be PUT

D. POST must include a resource ID in the URL

Solution

1. Step 1: Understand POST usage in REST

   POST is used to create new resources. The URL should point to the collection, not a specific resource ID.

2. Step 2: Analyze the request URL

   Including an ID (like /users/45) with POST is incorrect because the server assigns IDs when creating new resources.

3. Final Answer:

   The URL should be /users without ID for creating -> Option A

4. Quick Check:

   POST to collection URL without ID = correct [OK]

Hint: POST creates; URL should be collection without ID [OK]

Common Mistakes:

• Using POST with resource ID in URL
• Thinking POST updates existing resource
• Confusing POST and PUT URLs

5. You want to design an API to manage orders and their items. Which URL and HTTP method combination best follows resource-based design to update the quantity of item 7 in order 42?

hard

A. POST /orders/42/items with item ID and quantity in body

B. PUT /orders/42/items/7 with updated quantity in body

C. DELETE /orders/42/items/7 to update quantity

D. GET /orders/42/items/7 with quantity in query

Solution

1. Step 1: Identify the resource and action

   The resource is the specific item (ID 7) inside order 42. Updating quantity means modifying this resource.

2. Step 2: Choose correct HTTP method and URL

   PUT is used to update existing resources. The URL should point to the specific item resource: /orders/42/items/7.

3. Final Answer:

   PUT /orders/42/items/7 with updated quantity in body -> Option B

4. Quick Check:

   Update nested resource = PUT to specific item URL [OK]

Hint: Use PUT on specific nested resource URL to update it [OK]

Common Mistakes:

• Using POST to update existing item
• Using DELETE to update data
• Using GET with query to change data