rewriting to always use www in domain ( even on subpages ) - .htaccess

Question

I've added the following to my .htaccess to properly redirect any visitors from http://domain.com to http://www.domain.com ... but I still can't get it to work with subpages...ie http://domain.com/subpage is not yet redirecting to http://www.domain.com/subpage .
Here is what I have in my htaccess now:
<Files wp-config.php>
order allow,deny
deny from all
</Files>
<Files .htaccess>
order allow,deny
deny from all
</Files>
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
RewriteCond %{HTTP_HOST} !^www
RewriteRule (.*) http://www.%{HTTP_HOST}/$1 [L,R]
</IfModule>
So the question is what else would I need to add or update in my htaccess to get this working?
Many thanks for your suggestions!

Answer 1

You have the redirect happening after you've done routing to index.php, it needs to happen before any routing rules get executed. Try swapping them around:
RewriteEngine On
RewriteBase /
RewriteCond %{HTTP_HOST} !^www [NC]
RewriteRule (.*) http://www.%{HTTP_HOST}/$1 [L,R]
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
(also added the [NC] flag so case isn't checked in hostname match)