Error response format in Rest API - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to return a JSON error response with a message.

Rest API

return {"error": [1]

Drag options to blanks, or click blank then click option'

A"Invalid request"

BInvalid request

C'Invalid request'

Derror

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to put quotes around the error message string.

Using single quotes instead of double quotes in JSON.

The error message must be a string inside quotes in JSON format.

2fill in blank

medium

Complete the code to include an HTTP status code in the error response.

Rest API

return {"error": "Not found", "status": [1]

Drag options to blanks, or click blank then click option'

A404

B"404"

C'404'

Derror

Attempts:

3 left

💡 Hint

Common Mistakes

Putting quotes around the status code making it a string.

Using an incorrect status code number.

The status code should be a number, not a string, in the JSON response.

3fill in blank

hard

Fix the error in the JSON error response format.

Rest API

return {"error": "Unauthorized", [1]: 401}

Drag options to blanks, or click blank then click option'

Astatus

B"status"

C'status'

Dcode

Attempts:

3 left

💡 Hint

Common Mistakes

Using unquoted keys in JSON causing syntax errors.

Using single quotes instead of double quotes for keys.

JSON keys must be strings enclosed in double quotes.

4fill in blank

hard

Fill both blanks to create a detailed error response with message and code.

Rest API

return {"message": [1], "code": [2]

Drag options to blanks, or click blank then click option'

A"Invalid input"

B400

C"400"

D'Invalid input'

Attempts:

3 left

💡 Hint

Common Mistakes

Using single quotes for strings.

Putting quotes around numeric status codes.

The message must be a string with double quotes, and the code must be a number.

5fill in blank

hard

Fill all three blanks to return an error with message, code, and details.

Rest API

return {"message": [1], "code": [2], "details": [3]

Drag options to blanks, or click blank then click option'

A"Missing field"

B422

C["username", "password"]

D'Missing field'

Attempts:

3 left

💡 Hint

Common Mistakes

Using single quotes for strings or keys.

Quoting numbers or arrays incorrectly.

Message is a string with double quotes, code is a number, details is a JSON array.

Practice

1. What is the main purpose of an error response format in a REST API?

easy

A. To speed up the API response time

B. To clearly communicate what went wrong during a request

C. To encrypt the data sent to the client

D. To store user information securely

Solution

1. Step 1: Understand the role of error responses

   Error responses tell the client what problem happened when processing their request.

2. Step 2: Identify the main goal

   The main goal is to communicate the error clearly so the client can handle it properly.

3. Final Answer:

   To clearly communicate what went wrong during a request -> Option B

4. Quick Check:

   Error response purpose = clear communication [OK]

Hint: Error responses explain problems clearly to clients [OK]

Common Mistakes:

• Thinking error responses speed up API
• Confusing error format with encryption
• Assuming error responses store data

2. Which of the following is a correct JSON structure for a simple error response in a REST API?

easy

A. {"error": {"code": 404, "message": "Not Found"}}

B. {"status": 200, "message": "Success"}

C. {"data": {"id": 1, "name": "Item"}}

D. {"error_code": "404", "error_msg": "Not Found"}

Solution

1. Step 1: Identify standard error response keys

   Common keys include "error", "code", and "message" to describe the problem.

2. Step 2: Check each option

   {"error": {"code": 404, "message": "Not Found"}} uses "error" with "code" and "message" correctly in JSON format.

3. Final Answer:

   {"error": {"code": 404, "message": "Not Found"}} -> Option A

4. Quick Check:

   Standard error keys = code and message [OK]

Hint: Look for 'error', 'code', and 'message' keys in JSON [OK]

Common Mistakes:

• Confusing success response with error
• Using wrong key names like error_code
• Missing nested error object

3. Given this error response JSON:

{"error": {"code": 401, "message": "Unauthorized"}}

What HTTP status code should the API return?

medium

A. 401

B. 500

C. 404

D. 200

Solution

1. Step 1: Match error code to HTTP status

   The error code 401 means "Unauthorized", which is an HTTP status code for authentication failure.

2. Step 2: Confirm correct HTTP status

   The API should return HTTP status 401 to match the error code in the response body.

3. Final Answer:

   401 -> Option A

4. Quick Check:

   Error code 401 = HTTP status 401 [OK]

Hint: Match error code with HTTP status code [OK]

Common Mistakes:

• Returning 200 for error responses
• Confusing 401 with 404
• Using 500 for client errors

4. You receive this error response from an API:

{"error": {"code": "403", "message": "Forbidden"}}

But your client expects the code as an integer. What is the best fix?

medium

A. Change the message to "Access Denied"

B. Remove the code field entirely

C. Change the code value to an integer 403 in the response

D. Wrap the code in quotes to make it a string

Solution

1. Step 1: Identify data type mismatch

   The code is a string "403" but the client expects an integer 403.

2. Step 2: Fix the data type in the response

   Change the code value from a string to an integer to match client expectations.

3. Final Answer:

   Change the code value to an integer 403 in the response -> Option C

4. Quick Check:

   Match data types for code field [OK]

Hint: Ensure error code data type matches client expectation [OK]

Common Mistakes:

• Removing important error fields
• Changing message instead of code type
• Leaving code as string when integer needed

5. You want to design an error response format that includes an error code, a message, and optional details for debugging. Which JSON structure below best fits this need?

hard

A. {"error": "Bad Request", "code": 400}

B. {"status": "error", "code": 400, "msg": "Bad Request"}

C. {"error_code": 400, "error_message": "Bad Request"}

D. {"error": {"code": 400, "message": "Bad Request", "details": "Missing 'id' parameter"}}

Solution

1. Step 1: Check required fields in each option

   We need code, message, and optional details inside a clear error object.

2. Step 2: Evaluate each JSON structure

   {"error": {"code": 400, "message": "Bad Request", "details": "Missing 'id' parameter"}} includes all three: code, message, and details nested inside "error".

3. Final Answer:

   {"error": {"code": 400, "message": "Bad Request", "details": "Missing 'id' parameter"}} -> Option D

4. Quick Check:

   Include code, message, and details in error object [OK]

Hint: Include optional details inside error object for clarity [OK]

Common Mistakes:

• Omitting details field
• Using inconsistent key names
• Not nesting error info properly