1.Function Introduction

On National Proxy System, Individual Cache policy rules determine whether to cache or not based on traffic attributes, such as URL and Cookies.

2.Action

For cache action, the optimization parameters are:
  • A Cache key:is a unique string that lets the National Proxy System look for web content when requests hit them. It’s made up of a hostname, path, and cookie parts. By default, the Proxy use the entire URL as the cache key. Selecting the correct cache key will ensure maximum cache footprint and increase cache hits.
  • Ignore Query String in URL:in case the query strings doesn’t actually indicate that the object need to be different then you could EXCLUDE them from the cache key. For example, after ignoring “sqp” and “rs” of URL: “https://example.com/pic.jpg?sqp=UAAI&rs=AOn4”.
  • Include Cookie Values:in case the server send different content for the same URL based on the cookie value, you can include that cookie value as a part of cache key. For example, the server may set a cookie at the client called "prefLang=ru" to record user preferred language, you could add "prefLang" to distinguish different web content.
  • Disable Revalidate:is an ON-OFF switch. The pragma-no-cache header in a client’s request causes the proxy to re-fetch the entire object from the original server, even if the cached copy of the object is fresh. By default this option is switch OFF, which means a client’s non-conditional request results in a conditional GET request sent to the original server if the object is already in cache. The conditional request allows the original server to return the 304 Not Modified response, if the content in cache is still fresh. Thereby, the server-side bandwidth and latency consumed are lesser as the full content is not retrieved again from the original server.
  • Cache Dynamic Content:is an ON-OFF switch. A URL is considered dynamic if it ends in “.asp(x)” or contains a question mark (?), a semicolon (;), or “cgi”. Ignore Query String overrides this option (switch on).
  • Cache Cookied Content:is an ON-OFF switch. By default, the Proxy does NOT cache cookied content of any type. If this option is switch on, the system cache all Cookeid content except HTML.
  • Ignore Request no-cache Headers:is an ON-OFF switch. By default, the proxy strictly observes client Cache-Control: no-cache directives. As known as:
    • i. Authorization
    • ii. WWW-Authenticate
    • iii. Cache-Control: no-store
    • iv. Cache-Control: no-cache
  • If a requested object contains a no-cache header, then proxy forwards the request to the origin server even if it has a fresh copy in cache. You can configure proxy to ignore client no-cache directives such that it ignores no-cache headers from client requests and serves the object from its cache. Ignore Response no-cache Headers — is an ON-OFF switch. By default, a response from an origin server with a no-cache header is not stored in the cache. As known as:
    • i. Cache-Control: no-store
    • ii. Cache-Control: private
    • iii. Set-Cookie
    • iv. Cache-Control: no-cache
    • v. WWW-Authenticate
    • vi. Expires header with a value of 0 (zero) or a past date.
    If you configure proxy to ignore no-cache headers, then proxy also ignores no-store headers. The default behavior of observing no-cache directives is appropriate in most cases.
  • Forcing Object Caching: is an ON-OFF switch. You can force Proxy to cache specific URLs (including dynamic URLs) for a specified duration, regardless of Cache-Control response headers.
  • Minimum Use: sets the number of times an item must be requested by clients before Proxy caches it. This is useful if the cache is constantly filling up, as it ensures that only the most frequently accessed items are added to the cache. By default, Proxy cache object at its first appearance. The Counter resets in every 30 minutes. Note that the requests is counted in computing unit independently.
  • Max Cache Object Size: sets the upper limit of an object size, larger object will not be cached. By default, Proxy does not cache object larger than 1 GB.
  • Cache Pinning Time: configures Proxy to keep certain objects in the cache for a specified time. You can use this option to ensure that the most popular objects are in cache when needed and to prevent cache manager from deleting important objects. Proxy observes Cache-Control headers and pins an object in the cache only if it is indeed cacheable.
  • Max Cache Size: sets the upper limit of the size of storage for a policy. By default, Proxy uses all available disk space. When the cache size reaches the limit, the cache manager removes the files that were least recently used to bring the cache size back under the limit.
  • Inactive Time: specifies how long an item can remain in the cache without being accessed. A file that has not been requested for this time is automatically deleted from the cache by the cache manager, regardless of whether or not it has expired.