ETag Implementation

Overview

Implemented ETag-based optimistic locking in REST APIs, reducing concurrency conflicts and improving data consistency in distributed environments.

How ETags Work

1. Read Resource: Server returns ETag header with resource
2. Conditional Update: Client sends If-Match header with ETag
3. Conflict Detection: Server returns 412 if resource changed

Key Features

• Conflict Detection: Detect concurrent modifications
• Data Integrity: Prevent lost updates
• Clear Feedback: Inform clients of conflicts
• RFC 7232 Compliant: Standard HTTP implementation

Technical Approach

• Version-based ETag generation
• If-Match header validation
• Proper HTTP status codes (412 Precondition Failed)
• Minimal performance overhead