htaccess redirect only if domain matches

Question

I have a problem where I need to redirect my domain before it hits php. By the time it hits the ability to execute a header, it is too late.

How can I do

Answer 1

Using mod_rewrite

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

Answer 2

As of Apache 2.4 you can use an <If> Directive to achieve what you suggested:

<If "req('Host') == 'www.example.com'">
  RedirectMatch (.*) http://www.example2.com$1
</If>

For a case-insensitive version that matches with or without the www you can do:

<If "req('Host') =~ /example.com/i">
  RedirectMatch (.*) http://www.example2.com$1
</If>

Sources:

• Apache Blog: New in httpd 2.4: If, ElseIf, and Else
• Apache 2.4 Documentation: If Directive