Rewrite Rules

Control cache behavior by setting environment variables.
NOTE: X-LiteSpeed-* cache related response headers will overrule any storage settings, if applicable.


RewriteRule url1 - [E=cache-control:value1,E=cache-control:value2]
RewriteRule url2 - [E=cache-vary:value1,E=cache-control:value2]

Environment variables can have the following keys

Regular cache-control directives:
RewriteRule .* - [E=cache-control:max-age=300]
RewriteRule .* - [E=cache-control:private,max-age=300]

Flush private cache:
RewriteRule /flush_cache - [E=cache-control:flush]
You cannot flush the public cache through rewrite rules.

Disable auto flush private cache by POST request:
RewriteRule .* - [E=cache-control:no-autoflush]

Append a vary string to a cache object key directly:
RewriteRule url2 - [E=cache-control:vary=vary_value]
This directly appends vary_value to a cache key and a CGI environment variable
example: cache-control:vary=ismobile

Cache objects vary based on cookie values, this has the same effect as the X-LiteSpeed-Vary response header, the difference is that it only applies for the current request and it is not persistently associated with that URL.

For example: cache-vary:isloggedin
Makes cache varying on cookie value of isloggedin.

Another type of cache vary can be controlled without involving a cookie, the vary value is set directly via cache-control environment with special value vary=<vary_value> . Examples:
Cache response from browser with “mobi” signature as cache copy for mobile device for 5 minutes (300 seconds).
RewriteRule .* - [E=cache-control:max-age=300]
RewriteRule HTTP_USER_AGENT mobi [E=cache-control:vary=ismobile]

Rewrite Rules can also control the ESI engine for a request. To turn on the ESI engine for a request:
RewriteRule .* - [E=esi_on:1]

To turn off the ESI engine for a request:
RewriteRule .* - [E=esi_on:0]

Login Conflicts
If there are multiple web applications used for a single site, different cache varies should be used for login purposes to prevent cache conflicts. More information on this can be found here.

  • Admin
  • Last modified: 2018/05/29 21:14
  • by George Wang