Rule based cache processing in application delivery controller for load balancing

Abstract

Methods and systems for improving performance of an HTTP cache are provided. According to one embodiment, an HTTP request is received by an ADC for a resource associated with a server on behalf of which the ADC is performing load balancing. The ADC determines based on a local HTTP cache whether it can service the request. The request is parsed to identify a header. The existence or non-existence of locally cached content matching the request is identified by comparing portions of the identified header with corresponding portions of header information of cached content based on a vary rule defining when two headers are meaningfully different. Therefore, the identified header need not exactly match an entirety of the cached information for a cache hit to be found. Responsive to a cache hit, the ADC responds to the request with an HTTP response containing the identified locally cached content.