Graceful degradation in Rest API - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is graceful degradation in the context of REST APIs?

Graceful degradation means the API continues to work in a limited way even if some parts fail, so users still get useful responses instead of errors.

beginner

Why is graceful degradation important for REST APIs?

It helps keep the service reliable and user-friendly by providing fallback responses or partial data when some features or services are unavailable.

intermediate

Give an example of graceful degradation in a REST API.

If a user profile API can't fetch the user's recent posts due to a service failure, it still returns the basic profile info instead of a full error.

intermediate

How can you implement graceful degradation in REST APIs?

By using try-catch blocks, fallback data, default values, and meaningful error messages to handle failures without crashing the whole response.

advanced

What is the difference between graceful degradation and fail-fast in REST APIs?

Graceful degradation tries to keep the API working with limited features during failures, while fail-fast stops immediately and returns an error.

What does graceful degradation aim to provide in a REST API?

A Partial or fallback responses during failures

B Immediate failure with error messages

C Complete shutdown of the API

D Unlimited retries until success

Graceful degradation means the API still responds with partial or fallback data when some parts fail.

Which technique helps implement graceful degradation?

A Disabling the API during failures

B Ignoring errors silently

C Returning HTTP 500 for all errors

D Using try-catch blocks and fallback data

Try-catch blocks and fallback data allow the API to handle errors and still respond usefully.

If a REST API cannot fetch some data, what should it do for graceful degradation?

A Return a blank response

B Crash the server

C Return partial data with a warning

D Ignore the request

Returning partial data with a warning keeps the API useful even if some data is missing.

Graceful degradation improves which aspect of REST APIs?

A User experience during failures

B Speed of data processing

C Security of the API

D Database schema design

Graceful degradation helps users get useful responses even when parts of the API fail.

What is NOT a characteristic of graceful degradation?

A Error handling

B Complete failure without response

C Partial functionality

D Fallback responses

Graceful degradation avoids complete failure without response by providing fallback or partial data.

Explain in your own words what graceful degradation means for a REST API and why it matters.

Think about how an API can still be helpful even if some parts break.

Describe a simple example where a REST API uses graceful degradation to handle a service failure.

Imagine a user profile API missing some info but still returning basic details.

Practice

1. What is the main goal of graceful degradation in REST APIs?

easy

A. To keep the API working even if some parts fail

B. To stop the API immediately when an error occurs

C. To ignore all errors and continue without response

D. To make the API faster by skipping error checks

Solution

1. Step 1: Understand graceful degradation purpose

   Graceful degradation means the system still works even if some parts fail.

2. Step 2: Compare options with this meaning

   Only To keep the API working even if some parts fail matches this idea by keeping the API working despite failures.

3. Final Answer:

   To keep the API working even if some parts fail -> Option A

4. Quick Check:

   Graceful degradation = keep working despite failure [OK]

Hint: Graceful degradation means continue working despite errors [OK]

Common Mistakes:

• Thinking it stops the API on error
• Assuming errors are ignored without response
• Confusing with performance optimization

2. Which of the following is the correct way to handle errors for graceful degradation in a REST API response (in pseudocode)?

easy

A. ignore errors and return nothing

B. return data; if error then stop

C. try { return data } catch { return fallbackData }

D. throw error without handling

Solution

1. Step 1: Identify error handling syntax

   Graceful degradation uses try-catch to handle errors and provide fallback data.

2. Step 2: Match options to this pattern

   try { return data } catch { return fallbackData } shows try-catch with fallback, others either stop or ignore errors.

3. Final Answer:

   try { return data } catch { return fallbackData } -> Option C

4. Quick Check:

   Use try-catch with fallback for graceful degradation [OK]

Hint: Use try-catch to return fallback on error [OK]

Common Mistakes:

• Not catching errors properly
• Stopping API on first error
• Ignoring fallback responses

3. Consider this pseudocode for a REST API endpoint:

function getUserData() {
  try {
    return fetchUserFromDB();
  } catch (error) {
    return { name: "Guest", id: 0 };
  }
}

What will getUserData() return if the database fetch fails?

medium

A. An error message

B. Nothing, the function crashes

C. Null

D. A default user object with name 'Guest' and id 0

Solution

1. Step 1: Analyze try block behavior

   If fetchUserFromDB() works, it returns user data.

2. Step 2: Analyze catch block fallback

   If an error occurs, catch returns default user object with name 'Guest' and id 0.

3. Final Answer:

   A default user object with name 'Guest' and id 0 -> Option D

4. Quick Check:

   Error fallback returns default user object [OK]

Hint: Catch returns default object on failure [OK]

Common Mistakes:

• Assuming function crashes on error
• Expecting null instead of fallback object
• Thinking error message is returned

4. This REST API code snippet is meant to provide graceful degradation but has a bug:

function getData() {
  try {
    return fetchData();
  } catch (error) {
    fallbackData;
  }
}

What is the problem?

medium

A. The try block is missing

B. The fallback data is not returned in the catch block

C. The function does not catch errors

D. The function returns twice

Solution

1. Step 1: Check catch block code

   The catch block has fallbackData; but does not return it.

2. Step 2: Understand function return behavior

   Without return, the function returns undefined on error, breaking graceful degradation.

3. Final Answer:

   The fallback data is not returned in the catch block -> Option B

4. Quick Check:

   Catch must return fallback data for graceful degradation [OK]

Hint: Always return fallback data inside catch block [OK]

Common Mistakes:

• Forgetting to return fallback data
• Misplacing try-catch blocks
• Assuming catch auto-returns value

5. You have a REST API that fetches user profile and user posts separately. To apply graceful degradation, which approach is best?

hard

A. If fetching posts fails, return profile with empty posts list

B. If fetching posts fails, return error and no profile

C. Stop API if either profile or posts fail

D. Ignore profile and only return posts

Solution

1. Step 1: Understand graceful degradation in multi-part fetch

   It means returning partial data if one part fails, not stopping all.

2. Step 2: Evaluate options for partial fallback

   If fetching posts fails, return profile with empty posts list returns profile and empty posts if posts fail, matching graceful degradation.

3. Final Answer:

   If fetching posts fails, return profile with empty posts list -> Option A

4. Quick Check:

   Partial data returned on failure = graceful degradation [OK]

Hint: Return partial data with fallback for failed parts [OK]

Common Mistakes:

• Stopping API on any failure
• Returning no data if one part fails
• Ignoring fallback for partial data