mod_rewrite and double slash issue

Question

I applied the following mod_rewrite rule in Apache2 to redirect from non www to www:

RewriteEngine On
RewriteCond %{HTTP_HOST} ^example\.com$ [NC]
RewriteRule ^(.*)$ http://www.example.com/$1 [R=301,L]

I have two questions:

1) There's a double slash issue:

• When I go to http://www.example.com it correctly rewrites the URL to http://www.example.com/
• When I go to http://www.example.com/somepage, it correctly rewrites the URL to http://www.example.com/somepage
• If I go to http://example.com, it rewrites the URL to http://www.example.com// (double final slash)
• If I go to http://example.com/somepage, it correctly rewrites it to http://www.example.com/somepage

Any tips to fix it?

2) Is my configuration good for SEO?

Answer 1

Fixed with:

RewriteEngine On
RewriteCond %{HTTP_HOST} ^mydomain\.com$ [NC]
RewriteRule ^(.*)$ http://www.mydomain.com$1 [R=301,L]

because $1 by default contains the index path /

Answer 2

RewriteRule ^\/?(.*)$ http://www.mydomain.com/$1 [R=301,L]