How to debug Apache mod_rewrite

Question

I have two main problems with mod_rewrite:

1) There is no meaningful error reported when I have an invalid rule

Answer 1

One trick is to turn on the rewrite log. To turn it on,try these lines in your apache main config or current virtual host file (not in .htaccess):

RewriteEngine On
RewriteLog "/var/log/apache2/rewrite.log"
RewriteLogLevel 3

Since Apache httpd 2.4 mod_rewrite RewriteLog and RewriteLogLevel directives has been completely replaced by the new per-module logging configuration.

LogLevel alert rewrite:trace6