Precondition required

What it means

This write needs an If-Match header carrying the ETag (or the bare edit_seq) of the version being changed; GET the resource first.

What to do

GET the resource and send its ETag (or its bare edit_seq) as If-Match with the write.

Example

Sent as application/problem+json with status 428. detail varies with the request; branch on type.

{
  "type": "https://impartire.com/problems/precondition-required",
  "title": "Precondition required",
  "status": 428,
  "detail": "Send If-Match with the asset's ETag (or its edit_seq) from a GET.",
  "instance": "/api/v1/assets/6f1c2a4e-0b7d-4f7e-9a51-2d3c4b5a6e7f",
  "request_id": "01JB8Z5W6Q4N3X2V1T0S9R8P7M"
}