apache: basic authentication before rewrite

Question

I have an Apache in frontend that should redirect a request via a RewriteRule.

I have to put a basic authentication before the request is redirected, so

Answer 1

I solved putting the rewrite condition and rewrite rule outside the Locatio directive:

  AuthType Basic
  AuthName "Restricted Files"
  AuthUserFile /etc/httpd/conf/tag.pwd
  Require valid-user

RewriteCond %{LA-U:REMOTE_USER} !^$
RewriteRule ^/(.*) http://xxxxxx:xxx/$1   [P,L]

many thanks to h0tw1r3 for the suggestion

*Keep in mind that Location directives operate on URLs, and not directories. That means that if someone creates an alias to the document root, they'll completely bypass these authentication rules. (See http://httpd.apache.org/docs/2.0/mod/core.html#location for more.)