mod_rewrite and double slash issue - apache

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]
However, 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
Is my configuration good for SEO?

Answer 1

Fixed with:
RewriteEngine On
RewriteCond %{HTTP_HOST} ^example\.com$ [NC]
RewriteRule ^(.*)$ http://www.example.com$1 [R=301,L]
because $1 by default contains the index path /

Answer 2

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

Answer 3

Actually, you will always have double slashes due to
RewriteRule ^(.*)$ http://www.example.com/$1 [R=301,L]
combined with the fact that REQUEST_URI (that you are matching on) normally contains a starting slash. What you can try is RewriteRule ^(.*)$ http://example.com$1, and then send a broken HTTP request GET foo HTTP/1.0 and see if Apache deals with it properly.

Answer 4

Putting a slash into your pattern should resolve this issue:
RewriteRule ^/(.*)$ http://www.example.com/$1 [R=301,L]

Answer 5

That is because the root path is /, and you are appending whatever you get in RewriteRule (the first case works fine because it doesn't match the condition so no rewrite is performed).
You can try something like this:
RewriteEngine On
RewriteCond %{HTTP_HOST} ^example\.com$ [NC]
# for the home page
RewriteRule ^/$ http://www.example.com/ [R=301,L]
# for the rest of pages
RewriteRule ^(.*)$ http://www.example.com/$1 [R=301,L]