Automatically redirect Tor traffic to onion (Hopefully efficiently as the if processing isn't intensive)

crontab

##Get New Exit Node list ever 6 Hours
57 */6 * * * `curl https://check.torproject.org/cgi-bin/TorBulkExitList.py\?ip\=<yourip> | awk '{print $0" TOREX;"}' > /etc/nginx/includes/torexit.ips && service nginx restart`

nginx.conf

##Create a geo region for Tor Exits
geo $torexit {
    default        NOEXIT;
    include        includes/torexit.ips;
}

site.conf

##Check on every request if Tor Exit, potentially inefficient, but the geolookup is quicker than a long list of ifs. 
 if ($torexit = TOREX) {
        rewrite ^ https://xxxxxxxxxxxxxxxxxx.onion$request_uri? permanent;
}

That's really interesting; thanks, Chris - I'll look it over.

referenced in: https://trac.torproject.org/projects/tor/ticket/32256#comment:4

Can you explain how this works @CJFWeatherhead?

Can you explain how this works @CJFWeatherhead?

It creates a pseudo region (as though it was a geo-location) based on Tor's public list of exit nodes, it then rewrites requests from those IP's (which we can assume are Tor) and pushes them to an associated onion address.

This is however a little redundant now, the "correct" way of doing this is to use an Alt-Svc header, advertising the .onion service, which the user can configure in Tor Browser to auto-redirect if they choose to

Thanks @CJFWeatherhead, I appreciate it. It's a good solution.

So in a way, before the alt-svc header this concept was unique and then the TBB-team implemented another client side idea to solve the same problem?