htaccess multiple rewrite rules for different GET variables

Question

I am trying to use htaccess Rewrite Rules to map multiple GET variables, but not all the variables are required. I have ordered the variables so that x is always required, if y is set, then z must be set, etc. So I need the mappings to look like this:

example.com/section/topic/sub

to map to

example.com/?x=section&z=topic&y=sub

However the following code causes Internal Error, but if I only have one Rewrite Rule, it works.

Options +FollowSymLinks
Options -indexes
<IfModule mod_rewrite.c>
RewriteEngine on
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_URI}  ([^/]+)/?   [NC]
RewriteRule ^([^/]+)/([^/]+)/([^/]+)/([^/]+)$  ?x=$1&z=$2&y=$3&r=$4    [NC,L]
RewriteRule ^([^/]+)/([^/]+)/([^/]+)$  ?x=$1&z=$2&y=$3    [NC,L]
RewriteRule ^([^/]+)/([^/]+)$  ?x=$1&z=$2    [NC,L]
RewriteRule ^([^/]+)$  ?x=$1    [NC,L]

</IfModule>

I also need to ensure the url can have a trailing /, but does not require it.

As you can probably tell, I am new to htaccess.

Thank You

Answer 1

1. Don't know what RewriteCond %{REQUEST_URI} ([^/]+)/? is doing.
2. Make trailing slash optional by using /?$
3. Check for files/directories once at the top and skip applying the rules form them.

You can have your rules like this in DOCUMENT_ROOT/.htaccess:

Options +FollowSymLinks -indexes
<IfModule mod_rewrite.c>
RewriteEngine on
RewriteBase /

## If the request is for a valid directory
RewriteCond %{REQUEST_FILENAME} -d [OR]
## If the request is for a valid file
RewriteCond %{REQUEST_FILENAME} -f [OR]
## If the request is for a valid link
RewriteCond %{REQUEST_FILENAME} -l
## don't do anything
RewriteRule ^ - [L]


RewriteRule ^([^/]+)/([^/]+)/([^/]+)/([^/]+)/?$ ?x=$1&z=$2&y=$3&r=$4 [L,QSA]

RewriteRule ^([^/]+)/([^/]+)/([^/]+)/?$ ?x=$1&z=$2&y=$3 [L,QSA]

RewriteRule ^([^/]+)/([^/]+)/?$ ?x=$1&z=$2 [L,QSA]

RewriteRule ^([^/]+)/?$ ?x=$1 [L,QSA]

</IfModule>

Reference: Apache mod_rewrite Introduction