Partial success handling in Rest API - Mini Project: Build & Apply

Partial Success Handling in REST API Responses

📖 Scenario: You are building a REST API that processes multiple user requests in one call. Sometimes, some requests succeed while others fail. You want to handle this partial success properly and return a clear response.

🎯 Goal: Create a REST API endpoint that accepts a list of user IDs to fetch. The API should process each ID, return data for successful fetches, and report errors for failures in a single JSON response.

📋 What You'll Learn

Create a list of user IDs to fetch

Create a threshold or config variable to simulate failure for certain IDs

Use a loop to process each user ID and collect success or error results

Return a JSON response showing which user data was fetched and which failed

💡 Why This Matters

🌍 Real World

APIs often need to handle multiple requests at once and report which succeeded or failed without stopping the whole process.

💼 Career

Understanding partial success handling is important for backend developers building robust APIs that communicate clearly with clients.

1

DATA SETUP: Create a list of user IDs

Create a list called user_ids with these exact values: [101, 102, 103, 104, 105]

Rest API

# Create a list called user_ids with the values [101, 102, 103, 104, 105]
# Your code here

Hint

Use square brackets to create a list and separate values with commas.

2

CONFIGURATION: Set failure threshold

Create a variable called fail_threshold and set it to 103. This will simulate failure for user IDs greater than this value.

Rest API

user_ids = [101, 102, 103, 104, 105]
# Create a variable fail_threshold and set it to 103
# Your code here

Hint

Just assign the number 103 to the variable fail_threshold.

3

CORE LOGIC: Process user IDs with partial success handling

Create an empty dictionary called results. Use a for loop with variable user_id to iterate over user_ids. For each user_id, if it is less than or equal to fail_threshold, add an entry to results with key user_id and value {'status': 'success', 'data': f'UserData{user_id}'}. Otherwise, add an entry with value {'status': 'error', 'message': 'User not found'}.

Rest API

user_ids = [101, 102, 103, 104, 105]
fail_threshold = 103
# Create an empty dictionary results
# Use a for loop with user_id in user_ids
# Add success or error entries to results
# Your code here

Hint

Use an empty dictionary and a for loop. Use an if-else to decide success or error for each user_id.

4

OUTPUT: Print the JSON response showing partial success

Print the results dictionary.

Rest API

user_ids = [101, 102, 103, 104, 105]
fail_threshold = 103
results = {}
for user_id in user_ids:
    if user_id <= fail_threshold:
        results[user_id] = {'status': 'success', 'data': f'UserData{user_id}'}
    else:
        results[user_id] = {'status': 'error', 'message': 'User not found'}
# Print the results dictionary
# Your code here

Hint

Use print(results) to show the final dictionary.

Practice

1. What does HTTP 207 Multi-Status indicate in REST API partial success handling?

easy

A. Some parts of the request succeeded while others failed

B. The entire request failed due to server error

C. The request was redirected to another URL

D. The request was successful with no errors

Solution

1. Step 1: Understand HTTP 207 Multi-Status meaning

   HTTP 207 is used to report multiple status codes for different parts of a single request.

2. Step 2: Relate to partial success handling

   This status code indicates that some parts succeeded and others failed, providing detailed results.

3. Final Answer:

   Some parts of the request succeeded while others failed -> Option A

4. Quick Check:

   HTTP 207 = Partial success [OK]

Hint: 207 means mixed results, not full success or failure [OK]

Common Mistakes:

• Confusing 207 with 200 OK
• Thinking 207 means full failure
• Assuming 207 is a redirect status

2. Which of the following is the correct way to represent partial success in a REST API response?

easy

A. HTTP 404 with error message

B. HTTP 200 with empty body

C. HTTP 207 with JSON detailing success and failure

D. HTTP 500 with stack trace

Solution

1. Step 1: Identify correct HTTP status for partial success

   HTTP 207 Multi-Status is designed to show multiple results in one response.

2. Step 2: Confirm response format

   Using JSON to detail which parts succeeded or failed is the standard approach.

3. Final Answer:

   HTTP 207 with JSON detailing success and failure -> Option C

4. Quick Check:

   207 + JSON = Partial success response [OK]

Hint: Use 207 with JSON for partial success, not 200 or errors [OK]

Common Mistakes:

• Using 200 OK without details
• Returning 404 for partial success
• Sending server error 500 instead of partial status

3. Given this partial success JSON response, what is the status of item with ID 3?

{
  "responses": [
    {"id": 1, "status": "success"},
    {"id": 2, "status": "failure", "error": "Invalid data"},
    {"id": 3, "status": "success"}
  ]
}

medium

A. Failure due to invalid data

B. Success

C. Unknown status

D. Pending

Solution

1. Step 1: Locate item with ID 3 in JSON

   Item with ID 3 has "status": "success" in the responses array.

2. Step 2: Interpret the status value

   The status "success" means the operation for item 3 succeeded.

3. Final Answer:

   Success -> Option B

4. Quick Check:

   ID 3 status = success [OK]

Hint: Check the status field for the item ID in JSON [OK]

Common Mistakes:

• Confusing failure of other items with this one
• Assuming missing error means failure
• Ignoring the status field

4. You receive this HTTP response code and body from a batch update API:

HTTP/1.1 207 Multi-Status
{
  "results": [
    {"item": "A", "status": "success"},
    {"item": "B", "status": "fail", "error": "Timeout"}
  ]
}

What is the main issue in this response?

medium

A. Incorrect HTTP status code for partial success

B. JSON format is invalid

C. Missing Content-Type header

D. The status value "fail" should be "failure" or "error"

Solution

1. Step 1: Check HTTP status code usage

   HTTP 207 Multi-Status is correct for partial success.

2. Step 2: Verify status field values

   Common practice uses "success" and "failure" or "error"; "fail" is inconsistent and may cause confusion.

3. Final Answer:

   The status value "fail" should be "failure" or "error" -> Option D

4. Quick Check:

   Status values must be consistent and clear [OK]

Hint: Use standard status words like 'success' and 'failure' [OK]

Common Mistakes:

• Thinking 207 is wrong here
• Ignoring inconsistent status wording
• Assuming JSON is invalid without checking

5. You design a REST API endpoint that processes a list of user updates. Some updates succeed, others fail due to validation errors. How should you structure the response to clearly communicate partial success?

hard

A. Return HTTP 207 with a JSON array showing each user's update status and error if any

B. Return HTTP 400 with a generic error message for all failures

C. Return HTTP 200 with a simple success message ignoring failures

D. Return HTTP 500 with server error details

Solution

1. Step 1: Identify the need for partial success reporting

   Since some updates succeed and others fail, the response must show both results clearly.

2. Step 2: Choose appropriate HTTP status and response format

   HTTP 207 Multi-Status with detailed JSON per user update is the best practice to communicate partial success.

3. Final Answer:

   Return HTTP 207 with a JSON array showing each user's update status and error if any -> Option A

4. Quick Check:

   207 + detailed JSON = clear partial success [OK]

Hint: Use 207 and detailed JSON for mixed success/failure results [OK]

Common Mistakes:

• Ignoring failed updates in response
• Using 200 OK without details
• Returning generic errors instead of per-item status