412 / Precondition Failed

“The server does not meet one of the preconditions that the requester put on the request.“ — wikipedia

“The precondition given in one or more of the request-header fields evaluated to false when it was tested on the server. This response code allows the client to place preconditions on the current resource metainformation (header field data) and thus prevent the requested method from being applied to a resource other than the one intended.“ — ietf

412 / code reference(s)
Rails HTTP Status Symbol
:precondition_failed
← return