Prevent direct traffic to URL using htaccess - .htaccess

Question

I need to prevent direct access to a URL (http://www.example.com/gated-asset). Is there any way to add code to the htaccess file that would redirect all direct traffic to another page (http://www.example.com/form)?
I have tried the following code in my htaccess file, but all pages, including the home page, redirect to www.example.com/form.
RewriteEngine On
RewriteCond %{HTTP_REFERER} !^http://go.example.com [NC]
RewriteRule .* http://www.example.com/form [R,L]
The entire .htaccess file looks like this (it is a WordPress site):
# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
# END WordPress
RewriteEngine On
RewriteCond %{HTTP_REFERER} !^http://go.example.com [NC]
RewriteRule .* http://www.example.com/form [R,L]
I have also tried the following:
RewriteEngine on
RewriteCond %{HTTP_REFERER} !^http://go.example.com [NC]
RewriteRule ^/$ /form/ [R,L]
RewriteRule ^/$ /gated-asset/ [R,L]
As well as:
RewriteEngine on
RewriteCond %{HTTP_REFERER} !^http://go.example.com [NC]
RewriteRule http://www.example.com/gated-asset http://www.example.com/form/ [R,L]

Answer 1

You need to include http:// in the referrer check if you are matching the beginning (^). Unlike HTTP_HOST, HTTP_REFERER requires it. In addition, the referring URL may include a REQUEST_URI, and so closing the expression at the domain will prevent it from working.
RewriteEngine On
RewriteCond %{HTTP_REFERER} !^http://go.example.com [NC]
RewriteRule .* http://www.example.com/form [R,L]
If you don't want to include the http://, then you can use the following condition instead:
RewriteCond %{HTTP_REFERER} !go.example.com [NC]
However, I would recommend the first example be used.
Also included here are the R and L flags. R is implied if the rewrite is to an external resource, but it is generally better to include it.