Given that the existing home page has to remain the same until your ready to “activate” the new one. You can modify the .htaccess file so the WordPress site will only respond if the homepage has been called with a particular query string. This means you can test the WordPress build without interrupting the main index page.

In order to do this, you have to modify your .htaccess file in the website root. Below is the modified .htaccess file, take a backup before testing!


# BEGIN WordPress
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} !^/wp-content/
RewriteCond %{REQUEST_URI} !^/wp-includes/
RewriteRule . /$1/?test=true [L]
# END WordPress


Replace your existing .htaccess file with the code above and you are half way. Next modify your index.php in the wordpress site.


if(isset($_GET["test"])){
define('WP_USE_THEMES', true);
/* Loads the WordPress Environment and Template */
require('./wp-blog-header.php');
}else{
/* Your holding page HTML / include file */
}


You can redirect to, or include the existing index page within the else clause as described above. The links should still be intact because the .htaccess file is appending your url with the required query string.

So when you visit the site your existing homepage should remain the same. When you visit http://yoursite.com/?test=true your wordpress site should wake up and run accordingly.