Long-running operations (async responses) in Rest API - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the HTTP status code returned for an accepted long-running operation?

Consider a REST API that starts a long-running operation and immediately returns a response. What HTTP status code should the server return to indicate the request was accepted but processing is not complete?

A 202 Accepted

B 404 Not Found

C 200 OK

D 500 Internal Server Error

💡 Hint

Think about the status code that means the request is accepted but still processing.

The 202 Accepted status code means the server has accepted the request but the processing is not finished yet. This is common for long-running operations.

❓ Predict Output

intermediate

What is the typical HTTP header used to provide the URL for checking operation status?

When a long-running operation is accepted, the server often provides a URL where the client can check the status. Which HTTP header is commonly used to provide this URL?

A Location

B Retry-After

C Content-Type

D Authorization

💡 Hint

This header tells the client where to find the resource or status.

The Location header is used to provide the URL where the client can check the status of the long-running operation.

❓ Predict Output

advanced

What is the expected JSON response when polling a long-running operation that is still in progress?

A client polls the status URL of a long-running operation. The operation is still running. What JSON response should the server return to indicate this?

Rest API

HTTP/1.1 200 OK
Content-Type: application/json

{
  "status": "InProgress"
}

A { "status": "Unknown" }

B { "status": "Failed", "error": "Timeout" }

C { "status": "Completed", "result": {...} }

D { "status": "InProgress" }

💡 Hint

The status should clearly say the operation is still running.

When the operation is still running, the server returns a JSON with "status": "InProgress" to indicate the client should keep waiting.

❓ Predict Output

advanced

What is the correct final JSON response when a long-running operation completes successfully?

After polling, the long-running operation finishes successfully. What JSON response should the server return?

Rest API

HTTP/1.1 200 OK
Content-Type: application/json

{
  "status": "Succeeded",
  "result": {
    "message": "Operation completed"
  }
}

A { "status": "Failed", "error": "Timeout" }

B { "status": "InProgress" }

C { "status": "Succeeded", "result": { "message": "Operation completed" } }

D { "status": "Cancelled" }

💡 Hint

The status should indicate success and include the result.

The server returns "status": "Succeeded" and includes the result data when the operation finishes successfully.

🧠 Conceptual

expert

Which HTTP method is best suited for starting a long-running operation that creates a resource asynchronously?

You want to design a REST API where clients start a long-running operation that creates a new resource asynchronously. Which HTTP method should you use to start this operation?

A GET

B POST

C PUT

D DELETE

💡 Hint

Think about which method is used to create resources or trigger actions.

The POST method is used to create resources or trigger operations that may take time. GET is for reading, PUT for replacing, DELETE for removing.