Nested error reporting in Rest API - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this nested error response JSON?

Given this nested error response from a REST API, what is the value of the message field inside the details object?

Rest API

{
  "error": {
    "code": 400,
    "message": "Validation Failed",
    "details": {
      "field": "email",
      "message": "Invalid email format"
    }
  }
}

A "Validation Failed"

B "Invalid email format"

C "email"

D 400

💡 Hint

Look inside the nested 'details' object for the 'message' field.

The 'message' inside 'details' is 'Invalid email format'. The outer 'message' is 'Validation Failed'.

❓ Predict Output

intermediate

What HTTP status code is returned in this nested error response?

Look at this nested error response JSON. What is the HTTP status code indicated by the status field inside the error object?

Rest API

{
  "error": {
    "status": 404,
    "message": "Resource not found",
    "details": {
      "resource": "user",
      "id": "123"
    }
  }
}

A 404

B "Resource not found"

C 123

D "user"

💡 Hint

The status code is usually a number inside the 'error' object.

The 'status' field inside 'error' is 404, which is the HTTP status code.

🔧 Debug

advanced

Which option causes a JSON parsing error?

One of these nested error response JSON strings is invalid and will cause a parsing error. Which one?

A { "error": { "code": 403, "message": "Forbidden", "details": { "action": "Access denied" } } }

B { "error": { "code": 500, "message": "Server error", "details": { "info": "Unexpected failure" } } }

C { "error": { "code": 400, "message": "Bad request", "details": { "field": "name", "message": "Missing value" } }

D { "error": { "code": 401, "message": "Unauthorized", "details": { "reason": "Token expired" } } }

💡 Hint

Look for missing or extra brackets in the JSON strings.

Option C is missing the closing brace for the outer 'error' object, causing a JSON parsing error.

🧠 Conceptual

advanced

What is the main benefit of nesting error details in REST API responses?

Why do REST APIs often nest detailed error information inside an 'error' object rather than placing all fields at the top level?

A To reduce the size of the response by nesting fields

B To confuse the client and make debugging harder

C To make the response invalid JSON intentionally

D To organize error information clearly and separate it from other response data

💡 Hint

Think about clarity and structure in data.

Nesting error details helps keep error info organized and separate from normal data, making it easier to parse and understand.

❓ Predict Output

expert

What is the value of 'error.details.errors[1].message' in this nested error response?

Given this nested error response JSON, what is the value of the second error message inside the 'errors' list?

Rest API

{
  "error": {
    "code": 422,
    "message": "Validation Error",
    "details": {
      "errors": [
        {"field": "username", "message": "Required field"},
        {"field": "password", "message": "Too short"},
        {"field": "email", "message": "Invalid format"}
      ]
    }
  }
}

A "Too short"

B "Invalid format"

C "Required field"

D "Validation Error"

💡 Hint

Remember that list indexes start at 0.

The second error in the 'errors' list (index 1) has the message 'Too short'.