Symfony2 - Rewrite url to add www prefixwith existing .htacess file - apache

Question

Symfony2 core configuration comes up with the following .htacess file:
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.*)$ app.php [QSA,L]
</IfModule>
I understand that this will erase the app.php from the url in the browser.
I would like to add the following rewrite rule to add www. to my WebSite everytime a user enter the domain name without the www. :
RewriteCond %{HTTP_HOST} ^valutao\.com$ [NC]
RewriteRule ^(.*)$ http://www.valutao.com/$1 [L,R=301]
So now i have the following .htacess file:
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.*)$ app.php [QSA,L]
RewriteCond %{HTTP_HOST} ^valutao\.com$ [NC]
RewriteRule ^(.*)$ http://www.valutao.com/$1 [L,R=301]
</IfModule>
My issue is that app.php will show up again. It seems that my rule just hides the base configuration. Here is an example of what is displayed in the url when I enter valutao.com : http://www.valutao.com/app.php
Does someone know how to fix that. Unfortunately I have just basic knowledge with the rewrite rules.
Thanks for help

Answer 1

You simply need to change the order (www rewrite should go first).
I'd also make it less dependent on the domain name:
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{HTTP_HOST} !^www\.
RewriteRule ^(.*)$ http://www.%{HTTP_HOST}/$1 [R=301,L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.*)$ app.php [QSA,L]
</IfModule>