How to set HTTP headers (for cache-control)?

http browser-cache
andrew picture andrew · Dec 18, 2010 · Viewed 688.6k times · Source

How to enable browser caching for my site? Do I just put cache-control:public somewhere up in my header like this?

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"
Cache-Control:public;
>

I am using the latest version of PHP developing on the latest version of XAMPP.

Answer

Codemwnci picture Codemwnci · Dec 18, 2010

To use cache-control in HTML, you use the meta tag, e.g.

<meta http-equiv="Cache-control" content="public">

The value in the content field is defined as one of the four values below.

Some information on the Cache-Control header is as follows

HTTP 1.1. Allowed values = PUBLIC | PRIVATE | NO-CACHE | NO-STORE.

Public - may be cached in public shared caches.
Private - may only be cached in private cache.
No-Cache - may not be cached.
No-Store - may be cached but not archived.

The directive CACHE-CONTROL:NO-CACHE indicates cached information should not be used and instead requests should be forwarded to the origin server. This directive has the same semantics as the PRAGMA:NO-CACHE.

Clients SHOULD include both PRAGMA: NO-CACHE and CACHE-CONTROL: NO-CACHE when a no-cache request is sent to a server not known to be HTTP/1.1 compliant. Also see EXPIRES.

Note: It may be better to specify cache commands in HTTP than in META statements, where they can influence more than the browser, but proxies and other intermediaries that may cache information.

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