Hierarchical resource paths in Rest API - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a hierarchical resource path in REST APIs?

It is a way to organize API endpoints in a tree-like structure, showing relationships between resources using nested paths.

beginner

Why use hierarchical resource paths in REST APIs?

They help represent real-world relationships clearly, making APIs easier to understand and use by showing how resources are connected.

beginner

Example: How would you represent comments belonging to a specific blog post using hierarchical paths?

You would use a path like /posts/{postId}/comments, where {postId} identifies the blog post and comments are nested under it.

intermediate

What does the path /users/{userId}/orders/{orderId} represent?

It represents a specific order ({orderId}) that belongs to a specific user ({userId}), showing a clear parent-child relationship.

intermediate

How do hierarchical resource paths improve API security and validation?

They allow the server to check if a resource belongs to the parent resource, helping prevent unauthorized access and ensuring data integrity.

What does the hierarchical path /libraries/{libraryId}/books/{bookId} indicate?

A A book inside a specific library

B A library inside a specific book

C All books in all libraries

D A book unrelated to any library

The path shows that the book identified by {bookId} belongs to the library identified by {libraryId}.

Which is a correct hierarchical resource path for accessing all comments on a photo?

A /photos/{photoId}/comments

B /comments/photos

C /photos/comments

D /comments/{commentId}/photos

The path /photos/{photoId}/comments correctly nests comments under a specific photo.

Why is it better to use hierarchical paths instead of flat paths like /orders and /users separately?

A Flat paths are faster to process

B Hierarchical paths use fewer characters

C Hierarchical paths show relationships between resources clearly

D Flat paths are more secure

Hierarchical paths help show how resources relate, making the API easier to understand and use.

In the path /companies/{companyId}/employees/{employeeId}, what does {employeeId} represent?

A All employees in all companies

B An employee belonging to the company <code>{companyId}</code>

C A company belonging to the employee <code>{employeeId}</code>

D An unrelated employee

The employee identified by {employeeId} belongs to the company identified by {companyId}.

What is a benefit of hierarchical resource paths for API clients?

A They make URLs shorter

B They reduce the number of API calls needed

C They hide resource relationships

D They make it easier to find related resources

Hierarchical paths help clients understand and navigate related resources easily.

Explain what hierarchical resource paths are and why they are useful in REST APIs.

Think about how folders on your computer are organized.

Describe how you would design a hierarchical path for accessing all reviews of a specific product in an online store API.

Start from the main resource and add the related resource as a child.

Practice

1. What does a hierarchical resource path in a REST API represent?

easy

A. A nested structure showing relationships between resources

B. A random list of unrelated resources

C. A single resource without any relation

D. A method to encrypt API data

Solution

1. Step 1: Understand resource organization

   Hierarchical paths show how resources are connected, like folders inside folders.

2. Step 2: Identify the purpose of hierarchical paths

   They help represent parent-child relationships clearly in the API URL.

3. Final Answer:

   A nested structure showing relationships between resources -> Option A

4. Quick Check:

   Hierarchical paths = nested resource relationships [OK]

Hint: Think of folders inside folders to understand hierarchy [OK]

Common Mistakes:

• Confusing hierarchy with unrelated resource lists
• Ignoring the relationship between resources
• Thinking it's about data encryption

2. Which of the following is the correct syntax for a hierarchical resource path to access comments of a post with ID 10?

easy

A. /posts/10/comments

B. /comments/posts/10

C. /posts/comments/10

D. /10/posts/comments

Solution

1. Step 1: Identify the parent resource and its ID

   The parent resource is 'posts' with ID 10, so it comes first in the path.

2. Step 2: Append the child resource

   Comments belong to the post, so '/comments' follows '/posts/10'.

3. Final Answer:

   /posts/10/comments -> Option A

4. Quick Check:

   Parent resource + ID + child resource = /posts/10/comments [OK]

Hint: Parent resource and ID come before child resource [OK]

Common Mistakes:

• Placing child resource before parent
• Swapping resource names and IDs
• Using incorrect order of segments

3. Given the REST API path /users/5/orders/12/items, what resource does this path represent?

medium

A. All orders of all users

B. Order 12 of user 5

C. User 5's profile information

D. Items in order 12 of user 5

Solution

1. Step 1: Break down the path segments

   /users/5 means user with ID 5, /orders/12 means order with ID 12 for that user, and /items means the items in that order.

2. Step 2: Understand the full resource

   The path points to the items inside order 12 which belongs to user 5.

3. Final Answer:

   Items in order 12 of user 5 -> Option D

4. Quick Check:

   Path shows nested resources = items in order 12 of user 5 [OK]

Hint: Read path left to right as parent to child resources [OK]

Common Mistakes:

• Ignoring the nested order and item relationship
• Confusing order with user profile
• Assuming it lists all users or orders

4. Identify the error in this hierarchical REST API path: /projects//tasks/7

medium

A. Missing task ID before 7

B. Double slash between 'projects' and 'tasks' is invalid

C. Resource names should be capitalized

D. The path should end with a slash

Solution

1. Step 1: Check the path syntax

   The path has two slashes '//' between 'projects' and 'tasks', which is not valid in REST API paths.

2. Step 2: Understand correct path format

   Only one slash should separate resource names and IDs to maintain proper hierarchy.

3. Final Answer:

   Double slash between 'projects' and 'tasks' is invalid -> Option B

4. Quick Check:

   Only single slashes separate path segments [OK]

Hint: Check for extra or missing slashes in paths [OK]

Common Mistakes:

• Ignoring double slashes as harmless
• Thinking resource names must be capitalized
• Believing trailing slash is mandatory

5. You want to design a REST API path to access all reviews for a specific product variant. The product ID is 20 and the variant ID is 5. Which path correctly represents this hierarchical resource?

hard

A. /products/reviews/20/variants/5

B. /reviews/products/20/variants/5

C. /products/20/variants/5/reviews

D. /variants/5/products/20/reviews

Solution

1. Step 1: Identify the resource hierarchy

   Reviews belong to a variant, which belongs to a product. So the path should start with product ID, then variant ID, then reviews.

2. Step 2: Construct the path in correct order

   The correct order is /products/20/variants/5/reviews to show this nested relationship clearly.

3. Final Answer:

   /products/20/variants/5/reviews -> Option C

4. Quick Check:

   Parent to child order: product -> variant -> reviews [OK]

Hint: Order path segments from general to specific resource [OK]

Common Mistakes:

• Placing reviews before products or variants
• Mixing order of product and variant IDs
• Using unrelated resource order