Apache is not sending 304 response (if mod_deflate and AddOutputFilterByType is enabled)

Question

I have added the following line in my Apache httpd.conf: -

AddOutputFilterByType DEFLATE text/html text/css application/javascript application/x-javascript a         


        

Answer 1

This is a known bug in Apache. See Apache bug #45023, and summary of Apache 304 etags and mod_deflate.

Rebuilding from svn will fix the issue. The resolution was to revert the change that appended "-gzip" to the etag. However, there are associated HTTP compliance problems.

If you can't rebuild Apache, there is a suggested runtime configuration workaround in the bug report:

 RequestHeader  edit "If-None-Match" "^\"(.*)-gzip\"$" "\"$1\""
 Header  edit "ETag" "^\"(.*[^g][^z][^i][^p])\"$" "\"$1-gzip\""