htaccess 301 redirection using regular expression - .htaccess

Question

This is my current .htaccess file
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_URI} !(.*)/$
RewriteRule ^(.*)$ $1/
RewriteRule ^([^/]+)/$ index.php?p1=$1 [L]
RewriteRule ^([^/]+)/([^/]+)/$ index.php?p1=$1&p2=$2 [L]
RewriteRule ^([^/]+)/([^/]+)/([^/]+)/$ index.php?p1=$1&p2=$2&p3=$3 [L]
RewriteRule ^([^/]+)/([^/]+)/([^/]+)/([^/]+)/$ index.php?p1=$1&p2=$2&p3=$3&p4=$4 [L]
RewriteRule ^([^/]+)/([^/]+)/([^/]+)/([^/]+)/([^/]+)/$ index.php?p1=$1&p2=$2&p3=$3&p4=$4&p5=$5 [L]
Basically, it takes up to five "Friendly url folders" and assign the value to varibles and then, send those to my index.php page
IE: http://www.example.com/ford/focus/grey/
$p1 = 'ford';
$p2 = 'focus';
$p3 = 'grey';
$p3 = 'grey';
So far, so good.
Now, I need to integrate a 301 instruction (RegExp?) in that same .htaccess because initially, I had GET parameters like this :
IE: http://www.example.com/ford/focus/grey/?lang=fr
I need to get rid of all GET variables because Google sees it as duplicate content (even if I'm using the nofollow attribute on my languages links)
IE: http://i.want.to.keep/my/url/?AND_DUMP_GET_VARIABLES
http://www.example.com/ford/focus/grey/?lang=fr
http://www.example.com/ford/focus/grey/?lang=en
http://www.example.com/ford/focus/grey/?lang=sp
==> http://www.example.com/ford/focus/grey/
Logically, the instruction should be interpreted between the first and the second block but I just don't know where to start. Any hints?
THANKS!

Answer 1

As I understand you want to get rid of the QUERY STRING and redirect (301 Permanent Redirect) to the same URL but without QUERY STRING.
The rule below will redirect EVERY request that has query string:
RewriteCond %{QUERY_STRING} !^$
RewriteCond %{ENV:REDIRECT_STATUS} ^$
RewriteRule ^(.*)$ http://%{HTTP_HOST}/$1? [R=301,L]
1. The ? will do the magic -- will strip query string
2. You desperately need this line: RewriteCond %{ENV:REDIRECT_STATUS} ^$. The problem is that it may not work on your Apache setup and I cannot give you what exactly you need to make it work (it works fine on my vanilla Apache v2.2.17 on Windows).
After rewrite (internal redirect) occurred, it goes to next iteration and Apache starts matching all rules from the top again but for already rewritten URL. If we not add the above line, then mod_rewrite will apply the above rule to rewritten URL form and you will end up with all URLs get rewritten to /index.php with no parameters at all.
If the above will not work, then try the code below:
# do not do anything for already existing files and folders
RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule .+ - [L]
RewriteCond %{QUERY_STRING} !^$
RewriteRule ^(.*)$ http://%{HTTP_HOST}/$1? [R=301,L]
With help of # do not do anything for already existing files and folders rule, mod_rewrite will stop rewriting after URL will be rewritten to /index.php?p1=... format.
In case the above will not work at all (better -- in addition to the above -- I would suggest adding this anyway) use <link rel="canonical" href="FULL_PROPER_RUL"/> in your page:
http://googlewebmastercentral.blogspot.com/2009/02/specify-your-canonical.html
http://www.google.com/support/webmasters/bin/answer.py?answer=139394