Athenaeum

If-Match

Class: \Aedart\ETags\Preconditions\Rfc9110\IfMatch

Applicable

When If-Match header is requested.

Condition

  1. If If-Match header is "*", the condition is true if a current representation (Etag) exists for the target resource.
  2. If If-Match header is a list of Etags, the condition is true if any of the listed tags match the Etag of the selected representation (the resource).
  3. Otherwise, the condition is false.

When it passes

When condition passes, evaluation continues to If-None-Match precondition.

When it fails

If the request is state-changing, e.g. POST, PUT, PATCH... etc, the precondition will attempt to detect whether the requested state-change has already succeeded or not. This is done via the hasStateChangeAlreadySucceeded(), in the given resource. Should a state-change already have succeeded, then the abortStateChangeAlreadySucceeded() action method is invoked.

When the request is not state-changing, e.g. for GET, HEAD requests, or when a state-change could not be determined, the abortPreconditionFailed() action method is invoked.

References