AWS Certified Developer – Associate (DVA-C02) — Question 247

A developer has created a data collection application that uses Amazon API Gateway, AWS Lambda, and Amazon S3. The application’s users periodically upload data files and wait for the validation status to be reflected on a processing dashboard. The validation process is complex and time-consuming for large files.

Some users are uploading dozens of large files and have to wait and refresh the processing dashboard to see if the files have been validated. The developer must refactor the application to immediately update the validation result on the user’s dashboard without reloading the full dashboard.

What is the MOST operationally efficient solution that meets these requirements?

Answer options

• A. Integrate the client with an API Gateway WebSocket API. Save the user-uploaded files with the WebSocket connection ID. Push the validation status to the connection ID when the processing is complete to initiate an update of the user interface.
• B. Launch an Amazon EC2 micro instance, and set up a WebSocket server. Send the user-uploaded file and user detail to the EC2 instance after the user uploads the file. Use the WebSocket server to send updates to the user interface when the uploaded file is processed.
• C. Save the user’s email address along with the user-uploaded file. When the validation process is complete, send an email notification through Amazon Simple Notification Service (Amazon SNS) to the user who uploaded the file.
• D. Save the user-uploaded file and user detail to Amazon DynamoDB. Use Amazon DynamoDB Streams with Amazon Simple Notification Service (Amazon SNS) push notifications to send updates to the browser to update the user interface.

Correct answer: A

Explanation

Option A is the most operationally efficient solution because it uses WebSocket connections to push updates in real-time to the user interface without needing a full dashboard reload. Option B introduces unnecessary complexity by requiring an EC2 instance to manage WebSocket connections, which is less efficient. Option C relies on email notifications, which do not provide real-time updates. Option D suggests using DynamoDB Streams and SNS, which is more complex and less direct than using a WebSocket for immediate updates.