New capabilities

Users looking to write objects to IBM’s Cloud Object Storage systems may not want to write over an existing object and its associated information. This feature introduces a new header that allows S3 clients to prevent the overwrite of an existing object when making an object write request to a nonversioned bucket. Simply, if the client includes a forbid overwrite header with the value of `true` in the request, IBM Cloud Object Storage System verifies whether an object of the same name is present and rejects the request when that object exists.

Before the introduction of this header, S3 clients might have prevented overwrite of an existing object by using the http standard precondition `if-none-match` header.

But the benefit of this new header is that it aligns IBM’s S3 API with other S3 cloud APIs, allowing for better integration with other vendor SDKs.