Redirect based on REFERER from different pages of the same domain

Question

I'm looking for a .htaccess solution based on a REFERER from a specific page in the same domain:

Example #1

If a user clicks from the facebook homepage like:

https://www.facebook.com/

Redirect to:

https://www.mywebsite.com/targetpage

Example #2

If a user clicks from another page on Facebook, like:

https://www.facebook.com/ads/library/?somequery....

Redirect to:

https://www.mywebsite.com/

Answer 1

Try the following using mod_rewrite near the top of your .htaccess file:

RewriteEngine On

# Link from FB homepage
RewriteCond %{HTTP_REFERER} ^https://www\.facebook\.com/$
RewriteRule !^targetpage$ /targetpage [R=302,L]

# Link from another FB page
RewriteCond %{HTTP_REFERER} ^https://www\.facebook\.com/ads/library?somequery$
RewriteRule !^$ / [R=302,L]

You need to check that we are not already on the targetpage in order to avoid a redirect loop.

HOWEVER, (usual disclaimer about the HTTP Referer)... The HTTP Referer is unreliable at best. Particularly in modern browsers with the referrer-policy, since the referring website (eg. Facebook in this example) can control exactly what Referer header the browser is permitted to send.