Different nginx rules based on referrer

Solution 1:

I'm not familiar with WP Supercache, but if you just need to rewrite to index.php to avoid the cache it shouldn't be too difficult.

Your existing filter is not comprehensive since it only checks for google.com and google.co. According to this list, there are many TLDs that Google uses that won't match, such as google.de, google.fr, etc.

The following filter should limit you to referrers that begin with www.google and end with any combination of 2-3 character TLD.

if ($http_referer ~* ^www.google.[a-z]{2,3}(.[a-z]{2})?$ ) {
    # do whatever you need to do here to avoid caching
}

Solution 2:

You're almost there.

First, the WP Super Cache rules are very messy. They really need to be redesigned from the ground up, but that's a project for another day.

To get this working, don't return immediately, instead set the $supercache_uri = '' as all of the other checks do. For instance:

if ($http_referer ~* (www.google.com|www.google.co) ) {
    set $supercache_uri '';
}

This needs to appear AFTER the point where $supercache_uri is originally set, and not at the beginning where you have it.