Graceful degradation in Rest API - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to return a fallback message when the main API call fails.

Rest API

response = call_main_api()
if not response:
    return [1]

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

Aresponse.json()

B"Success"

C"Service unavailable, please try later."

Dcall_backup_api()

Attempts:

3 left

💡 Hint

Common Mistakes

Returning the original response without checking if it failed.

Calling the main API again instead of returning a fallback message.

When the main API call fails (response is None or False), we return a fallback message to inform the user gracefully.

2fill in blank

medium

Complete the code to call a backup API if the main API call fails.

Rest API

response = call_main_api()
if not response:
    response = [1]

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

ANone

Bcall_main_api()

Creturn "Error"

Dcall_backup_api()

Attempts:

3 left

💡 Hint

Common Mistakes

Calling the main API again instead of the backup.

Returning an error message instead of trying the backup.

If the main API call fails, we try the backup API to keep the service working.

3fill in blank

hard

Fix the error in the code to handle API failure gracefully.

Rest API

try:
    data = call_main_api()
except Exception:
    data = [1]

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

Acall_backup_api()

Braise

CNone

Dprint('Error')

Attempts:

3 left

💡 Hint

Common Mistakes

Re-raising the exception instead of handling it.

Setting data to None without fallback.

When the main API call raises an exception, we catch it and call the backup API to degrade gracefully.

4fill in blank

hard

Fill both blanks to create a dictionary with API data or fallback values.

Rest API

result = {
    "status": [1],
    "data": [2]
}

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

A"success"

Bcall_main_api()

CNone

D"failed"

Attempts:

3 left

💡 Hint

Common Mistakes

Using a function call directly instead of a string for status.

Setting data to a string instead of None.

We set status to 'success' and data to None as a fallback when no data is available.

5fill in blank

hard

Fill all three blanks to build a graceful degradation response dictionary.

Rest API

response = {
    "status": [1],
    "message": [2],
    "data": [3]
}

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

A"error"

B"Service temporarily unavailable"

CNone

D"success"

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'success' status when there is an error.

Providing data instead of None when service is down.

When the service fails, status is 'error', message explains the issue, and data is None.

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