Currently this is only available for tracker artifacts.
Every time you fetch an artifact via the route
GET /artifacts/:id, it will return several headers.
Among them there are two that allow you to detect the version of your artifact and ensure you will not
overwrite changes that happened between the time you last fetched your artifact and your current update.
These headers are
Etag: a hash of the current artifact version
Last-Modified: a timestamp of the last modification
If you want to ensure that your call to
PUT /artifacts/:id updates the latest version then you need to tell
the server so. To do this, you need to send your own headers in the request. You must send at least one of
If-match- with the value you received in the Etag header when you last fetched the artifact, or
If-Unmodified-Since: with the timestamp received in the Last-Modified header
As you can see, these headers go in pairs:
(Etag/ If-match) and
If the value you provide does not match the value of the current version of the artifact, the API will throw
412 precondition failed.
Note: if you do not provide either the
If-Unmodified-Since headers in your
request then no concurrency check will be done and the artifact will be overwritten.