Problem Details (RFC 7807) format in Rest API - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this RFC 7807 JSON example?

Given this JSON response following RFC 7807, what is the value of the title field?

Rest API

{
  "type": "https://example.com/probs/out-of-credit",
  "title": "You do not have enough credit.",
  "status": 403,
  "detail": "Your current balance is 30, but that costs 50.",
  "instance": "/account/12345/msgs/abc"
}

A Your current balance is 30, but that costs 50.

B https://example.com/probs/out-of-credit

C /account/12345/msgs/abc

D You do not have enough credit.

💡 Hint

Look for the title key in the JSON object.

The title field in RFC 7807 provides a short, human-readable summary of the problem type. Here, it is "You do not have enough credit."

🧠 Conceptual

intermediate

Which field in RFC 7807 is used to uniquely identify the specific occurrence of the problem?

In the Problem Details JSON format, which field uniquely identifies the specific occurrence of the problem?

A instance

B title

C type

D status

💡 Hint

It is a URI reference that identifies the specific occurrence.

The instance field is a URI reference that identifies the specific occurrence of the problem, allowing clients to distinguish between different occurrences.

❓ Predict Output

advanced

What HTTP status code is represented in this RFC 7807 response?

Given this JSON snippet, what is the HTTP status code indicated?

Rest API

{
  "type": "https://example.com/probs/invalid-input",
  "title": "Invalid input provided.",
  "status": 422,
  "detail": "The 'email' field must be a valid email address.",
  "instance": "/users/abc123"
}

A 400

B 422

C 500

D 404

💡 Hint

Check the status field in the JSON.

The status field indicates the HTTP status code. Here it is 422, which means Unprocessable Entity.

❓ Predict Output

advanced

What is the output of this Python code parsing an RFC 7807 response?

Consider this Python code that parses an RFC 7807 JSON response. What does it print?

Rest API

import json

response = '''{
  "type": "https://example.com/probs/out-of-credit",
  "title": "You do not have enough credit.",
  "status": 403,
  "detail": "Your current balance is 30, but that costs 50.",
  "instance": "/account/12345/msgs/abc"
}'''

problem = json.loads(response)
print(problem.get('detail'))

A https://example.com/probs/out-of-credit

B You do not have enough credit.

C Your current balance is 30, but that costs 50.

D /account/12345/msgs/abc

💡 Hint

Look at the key used in problem.get().

The code prints the value of the detail key, which is "Your current balance is 30, but that costs 50."

🧠 Conceptual

expert

Which statement about the 'type' field in RFC 7807 is correct?

Choose the correct statement about the type field in the Problem Details (RFC 7807) format.

A It is a URI that identifies the problem type and should always be dereferenceable to human-readable documentation.

B It is a short human-readable summary of the problem type.

C It is a URI reference that identifies the specific occurrence of the problem.

D It is the HTTP status code associated with the problem.

💡 Hint

Think about the purpose of the type field as defined in RFC 7807.

The type field is a URI that identifies the problem type. It is recommended to be dereferenceable to human-readable documentation, but it is not mandatory. It helps clients understand the kind of problem.

Practice

1. What is the main purpose of the Problem Details (RFC 7807) format in REST APIs?

easy

A. To speed up API response times

B. To standardize error responses so clients can understand errors better

C. To encrypt API responses for security

D. To format successful data responses uniformly

Solution

1. Step 1: Understand the role of Problem Details format

   The format is designed to provide a consistent way to report errors in APIs.

2. Step 2: Identify the main benefit

   It helps clients understand and handle errors better by standardizing error responses.

3. Final Answer:

   To standardize error responses so clients can understand errors better -> Option B

4. Quick Check:

   Purpose = Standardize error responses [OK]

Hint: Remember: Problem Details = standardized error info [OK]

Common Mistakes:

• Confusing error format with data encryption
• Thinking it speeds up API responses
• Assuming it formats successful responses

2. Which of the following is a REQUIRED field in the Problem Details JSON object according to RFC 7807?

easy

A. type

B. status

C. detail

D. instance

Solution

1. Step 1: Recall required fields in RFC 7807

   The RFC requires the "type" field to identify the error type URI.

2. Step 2: Check other fields

   Fields like "status", "detail", and "instance" are optional but recommended.

3. Final Answer:

   type -> Option A

4. Quick Check:

   Required field = type [OK]

Hint: Only 'type' is mandatory in Problem Details [OK]

Common Mistakes:

• Assuming 'status' is required
• Confusing 'detail' as mandatory
• Thinking 'instance' is always needed

3. Given this Problem Details JSON response:

{"type": "https://example.com/probs/out-of-credit", "title": "You do not have enough credit.", "status": 403, "detail": "Your current balance is 30, but that costs 50.", "instance": "/account/12345/msgs/abc"}

What is the HTTP status code indicated?

medium

A. 403

B. 404

C. 200

D. 500

Solution

1. Step 1: Locate the status field in JSON

   The JSON has "status": 403, which indicates the HTTP status code.

2. Step 2: Understand the meaning of 403

   403 means Forbidden, matching the error about insufficient credit.

3. Final Answer:

   403 -> Option A

4. Quick Check:

   Status code = 403 [OK]

Hint: Look for 'status' field for HTTP code [OK]

Common Mistakes:

• Confusing status with 'detail' content
• Picking 200 as success code
• Ignoring the numeric status field

4. You receive this Problem Details JSON:

{"title": "Invalid input", "status": 400, "detail": "Missing required field 'name'"}

What is missing that violates RFC 7807 requirements?

medium

A. The 'title' field should be a URL

B. The 'status' field should be a string

C. The 'detail' field should be omitted

D. The 'type' field is missing

Solution

1. Step 1: Check required fields in the JSON

   The 'type' field is required by RFC 7807 but is missing here.

2. Step 2: Validate other fields

   'status' is correctly a number, 'detail' and 'title' are valid types.

3. Final Answer:

   The 'type' field is missing -> Option D

4. Quick Check:

   Missing required field = type [OK]

Hint: Always include 'type' field in Problem Details [OK]

Common Mistakes:

• Thinking 'status' must be string
• Removing 'detail' field
• Assuming 'title' must be URL

5. You want to create a Problem Details response for a rate limit error. Which JSON object correctly follows RFC 7807 and clearly informs the client about the error?

hard

A. {"type": "rate-limit", "title": "Error", "status": 429, "detail": "Limit reached"}

B. {"title": "Rate limit exceeded", "status": "429", "detail": "Too many requests", "instance": "/api/v1/resource"}

C. {"type": "https://example.com/probs/rate-limit", "title": "Rate limit exceeded", "status": 429, "detail": "You have sent too many requests in a short time.", "instance": "/api/v1/resource"}

D. {"type": "https://example.com/probs/rate-limit", "title": "Rate limit exceeded", "status": 200, "detail": "Too many requests"}

Solution

1. Step 1: Check required fields and correct types

   {"type": "https://example.com/probs/rate-limit", "title": "Rate limit exceeded", "status": 429, "detail": "You have sent too many requests in a short time.", "instance": "/api/v1/resource"} includes 'type' as a URI, 'title', numeric 'status' 429, 'detail', and 'instance' fields correctly.

2. Step 2: Validate status code and clarity

   Status 429 means Too Many Requests, matching the error. Other options have missing or wrong fields or wrong status codes.

3. Final Answer:

   {"type": "https://example.com/probs/rate-limit", "title": "Rate limit exceeded", "status": 429, "detail": "You have sent too many requests in a short time.", "instance": "/api/v1/resource"} -> Option C

4. Quick Check:

   Correct fields and status = {"type": "https://example.com/probs/rate-limit", "title": "Rate limit exceeded", "status": 429, "detail": "You have sent too many requests in a short time.", "instance": "/api/v1/resource"} [OK]

Hint: Use URI in 'type' and correct numeric 'status' [OK]

Common Mistakes:

• Using string instead of number for status
• Missing 'type' or using non-URI string
• Wrong HTTP status code for error