Self link for current resource in Rest API - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a self link in a REST API?

A self link is a URL included in a REST API response that points to the current resource itself. It helps clients easily find or refresh the resource.

beginner

Why include a self link in a REST API response?

Including a self link improves navigation by letting clients know the exact URL of the current resource, making it easier to update or retrieve it again.

beginner

How is a self link typically represented in a REST API JSON response?

It is often included as a field named "self" or under a "links" object, containing the URL string of the current resource.

beginner

Give an example of a self link in a REST API response.

Example: { "id": 1, "name": "Item", "links": { "self": "https://api.example.com/items/1" } }

intermediate

What is the benefit of using self links in REST APIs for client applications?

Self links allow clients to easily find the resource URL without constructing it manually, reducing errors and simplifying client code.

What does a self link in a REST API response point to?

A The API documentation

B The current resource itself

C A related but different resource

D The server status page

A self link always points to the current resource, allowing clients to access or refresh it.

Where is a self link usually found in a JSON REST API response?

A Inside a "links" object or a "self" field

B In the HTTP headers only

C In the request body

D In the server logs

Self links are typically included in the JSON response body under a "links" object or a "self" field.

Why is including a self link helpful for REST API clients?

A It helps clients find the exact URL of the resource easily

B It increases server load

C It hides the resource URL

D It encrypts the resource data

Self links provide clients with the exact URL to access or update the resource, simplifying client logic.

Which of these is a correct example of a self link URL?

A mailto:[e-mail]

B ftp://files.example.com/items/123

C https://api.example.com/items/123

D file:///C:/items/123

A self link is a valid HTTP or HTTPS URL pointing to the resource; ftp, mailto, or file URLs are not typical for REST API self links.

What is the main purpose of hypermedia links like self links in REST APIs?

A To slow down the API response

B To compress data

C To store user passwords

D To guide clients through available actions and resources

Hypermedia links help clients navigate the API by providing URLs for related resources and actions.

Explain what a self link is in a REST API and why it is useful.

Think about how a client can find the URL of the resource it just received.

Describe how you would include a self link in a JSON response for a resource with ID 42.

Show a small JSON snippet with a self link URL.

Practice

1. What is the main purpose of a self link in a REST API response?

easy

A. To provide the URL of the current resource for easy access

B. To link to a related but different resource

C. To show the API version used

D. To list all available endpoints in the API

Solution

1. Step 1: Understand the role of self link

   The self link points to the current resource's URL, allowing clients to access or refresh it easily.

2. Step 2: Differentiate from other links

   Other links may point to related resources or metadata, but self specifically means the current resource.

3. Final Answer:

   To provide the URL of the current resource for easy access -> Option A

4. Quick Check:

   Self link = current resource URL [OK]

Hint: Self link always points to the current resource URL [OK]

Common Mistakes:

• Confusing self link with related resource links
• Thinking self link shows API version
• Assuming self link lists all endpoints

2. Which of the following is the correct JSON structure to include a self link for a resource with URL https://api.example.com/items/42?

easy

A. {"links": {"self_link": "https://api.example.com/items/42"}}

B. {"_links": {"self": "https://api.example.com/items/42"}}

C. {"_links": {"current": "https://api.example.com/items/42"}}

D. {"self": "https://api.example.com/items/42"}

Solution

1. Step 1: Identify the standard key names

   The standard way is to use an object named _links containing a self key with the URL string.

2. Step 2: Compare options

   {"_links": {"self": "https://api.example.com/items/42"}} matches the standard exactly. Others use wrong keys or structure.

3. Final Answer:

   {"_links": {"self": "https://api.example.com/items/42"}} -> Option B

4. Quick Check:

   Use _links with self key for self link [OK]

Hint: Use _links object with self key for self link [OK]

Common Mistakes:

• Using 'links' instead of '_links'
• Using 'self_link' or 'current' instead of 'self'
• Placing self URL outside _links object

3. Given this API response snippet, what is the URL to access the current resource?

{
  "id": 10,
  "name": "Book",
  "_links": {
    "self": "https://api.example.com/products/10",
    "category": "https://api.example.com/categories/5"
  }
}

medium

A. https://api.example.com/products/10

B. https://api.example.com/products

C. https://api.example.com/categories/5

D. https://api.example.com/

Solution

1. Step 1: Locate the self link in the _links object

   The self link is under _links with key self, value is the current resource URL.

2. Step 2: Identify the URL value

   The value is "https://api.example.com/products/10", which is the URL for this product resource.

3. Final Answer:

   https://api.example.com/products/10 -> Option A

4. Quick Check:

   Self link URL = https://api.example.com/products/10 [OK]

Hint: Find _links.self for current resource URL [OK]

Common Mistakes:

• Choosing related links like category URL
• Picking base API URL instead of self
• Ignoring the _links object structure

4. You receive this JSON response but the self link is missing:

{
  "id": 5,
  "title": "Article",
  "_links": {
    "related": "https://api.example.com/articles/related"
  }
}

What is the best fix to add a self link for the current resource at https://api.example.com/articles/5?

medium

A. Add "self": "https://api.example.com/articles/5" at the root level

B. Add "self_link": "https://api.example.com/articles/5" inside the _links object

C. Add "self": "https://api.example.com/articles/5" inside the _links object

D. Add "link": "https://api.example.com/articles/5" inside the _links object

Solution

1. Step 1: Identify where self link belongs

   The self link must be inside the _links object with key exactly "self".

2. Step 2: Choose correct key and location

   Add "self": "https://api.example.com/articles/5" inside the _links object adds the correct key "self" with the URL inside _links. Other options use wrong keys or wrong placement.

3. Final Answer:

   Add "self": "https://api.example.com/articles/5" inside the _links object -> Option C

4. Quick Check:

   Self link key = "self" inside _links [OK]

Hint: Self link must be 'self' key inside _links object [OK]

Common Mistakes:

• Using wrong key names like self_link or link
• Placing self link outside _links object
• Omitting the self link entirely

5. You want to design a REST API response for a user resource with ID 7. Which JSON snippet correctly includes a self link and a related link to the user's orders at https://api.example.com/users/7/orders?

hard

A. {
"id": 7,
"name": "Alice",
"_links": {
"self": "https://api.example.com/users/7",
"related": "https://api.example.com/users/7/orders"
}
}

B. {
"id": 7,
"name": "Alice",
"links": {
"self": "https://api.example.com/users/7",
"orders": "https://api.example.com/users/7/orders"
}
}

C. {
"id": 7,
"name": "Alice",
"_links": {
"self_link": "https://api.example.com/users/7",
"orders_link": "https://api.example.com/users/7/orders"
}
}

D. {
"id": 7,
"name": "Alice",
"_links": {
"self": "https://api.example.com/users/7",
"orders": "https://api.example.com/users/7/orders"
}
}

Solution

1. Step 1: Confirm self link key and URL

   The self link must be under _links with key "self" and URL "https://api.example.com/users/7".

2. Step 2: Choose appropriate key for related orders link

   Using "orders" for the orders link is a standard practice to indicate the related resource. { "id": 7, "name": "Alice", "_links": { "self": "https://api.example.com/users/7", "orders": "https://api.example.com/users/7/orders" } } uses "orders" correctly.

3. Step 3: Check other options for correctness

   { "id": 7, "name": "Alice", "_links": { "self": "https://api.example.com/users/7", "orders": "https://api.example.com/users/7/orders" } } uses "orders" key which is standard. { "id": 7, "name": "Alice", "links": { "self": "https://api.example.com/users/7", "orders": "https://api.example.com/users/7/orders" } } uses "links" instead of "_links". { "id": 7, "name": "Alice", "_links": { "self_link": "https://api.example.com/users/7", "orders_link": "https://api.example.com/users/7/orders" } } uses non-standard keys "self_link" and "orders_link". The option with "related": "https://api.example.com/users/7/orders" uses a generic rel name which is less descriptive for the specific orders resource.

4. Final Answer:

   { "id": 7, "name": "Alice", "_links": { "self": "https://api.example.com/users/7", "orders": "https://api.example.com/users/7/orders" } } -> Option D

5. Quick Check:

   Use _links with self and orders keys for current and orders URLs [OK]

Hint: Use _links with self and orders keys for current and orders URLs [OK]

Common Mistakes:

• Using 'links' instead of '_links'
• Using non-standard keys like self_link
• Using generic 'related' instead of specific 'orders'