US Patent 9634905 Invalidation systems, methods, and devices

A computer-implemented method includes receiving, at a service running on the hardware, invalidation information relating to one or more resources; and determining whether the invalidation information relates to any resources currently stored on the service. Based on the determining, when the invalidation information relates to at least one resource not currently cached on the service, maintaining on the service at least some of the invalidation information; and using the maintained invalidation information on the service to prevent subsequent use of a version of at least one resource not currently stored on the service.