API ETag and Optimistic Concurrency

Optimistic concurrency control for REST API write operations is enforced by requiring clients to send an ETag in the If-Match header, which the server validates against a database version column before processing updates.

The HTTP If-Match header is used for API version checking by carrying the ETag value, allowing the server to verify the client's version of the resource matches the current database state and prevent concurrent overwrites.

To prevent concurrent modifications from overwriting data, implement ETag verification that gracefully rejects conflicting write operations, ensuring clients refetch the resource before attempting to update it again.

Yes, ETag-based consistency checks require a version column in the database to automatically increment and verify the resource version during write operations, maintaining client-server data integrity.

When the If-Match ETag value is outdated, the API handles version conflicts by rejecting the write operation gracefully, preventing the overwrite and forcing the client to retrieve the latest resource version.

Yes, optimistic concurrency control can be used for DELETE operations on REST APIs by requiring the If-Match header with the ETag, ensuring the resource has not been modified before deletion is processed.