Google Analytics Proxy using Nginx to bypass Adblock and other blockers

1.google-analytics-proxy-nginx.conf

server {
    listen 80;
    server_name your.domain.com;

    location = /analytics.js {
        # you have to compile nginx with http://nginx.org/en/docs/http/ngx_http_sub_module.html (this is not default)
        # and http://nginx.org/en/docs/http/ngx_http_proxy_module.html (it's a default module)
        
        proxy_set_header Accept-Encoding "";
        sub_filter 'www.google-analytics.com'  'your.domain.com';
        sub_filter_types *;
        sub_filter_once off;

        proxy_pass https://www.google-analytics.com/analytics.js;
        break;
    }

    location / {
        proxy_pass http://www.google-analytics.com/;
    }
}

2.browser-javascript-file.js

(function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
  (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
  m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
})(window,document,'script','//your.domain.com/analytics.js','ga');

# after this run your regular ga code
ga('create', 'UA-XXXXXXX-Y', 'auto');

ga('set', 'userId', 'your logged user id');

ga('send', 'pageview');

This basically proxy all requests to google analytics, including the analytics.js download.
After download analytics.js the content of file is changed by nginx, replacing regular 'www.google-analytics.com' urls to your proxy domain.
So all your requests from your frontend will go to your proxy.
For it works, you just need to replace the redular '//www.google-analytics.com/analytics.js' in the frontend by '//your.domain.com/analytics.js'. Nothing else! Really!

if you are using cloudflare use real ip module to get the ip and set it in proxy query string
http://nginx.org/en/docs/http/ngx_http_realip_module.html

add this lines inside "server" block:

set_real_ip_from 103.21.244.0/22;
set_real_ip_from 103.22.200.0/22;
set_real_ip_from 103.31.4.0/22;
set_real_ip_from 104.16.0.0/12;
set_real_ip_from 108.162.192.0/18;
set_real_ip_from 131.0.72.0/22;
set_real_ip_from 141.101.64.0/18;
set_real_ip_from 162.158.0.0/15;
set_real_ip_from 172.64.0.0/13;
set_real_ip_from 173.245.48.0/20;
set_real_ip_from 188.114.96.0/20;
set_real_ip_from 190.93.240.0/20;
set_real_ip_from 197.234.240.0/22;
set_real_ip_from 198.41.128.0/17;
set_real_ip_from 2400:cb00::/32;
set_real_ip_from 2606:4700::/32;
set_real_ip_from 2803:f800::/32;
set_real_ip_from 2405:b500::/32;
set_real_ip_from 2405:8100::/32;
set_real_ip_from 2c0f:f248::/32;
set_real_ip_from 2a06:98c0::/29;

# use any of the following two
real_ip_header CF-Connecting-IP;

and then change the proxy_pass to:
proxy_pass http://www.google-analytics.com/$uri$is_args$args&uip=$remote_addr;

Hi @paivaric,

I checked my configuration several times; I'm pretty sure I didn't make any mistake in following your instructions.

However, I'm getting a lot of these errors:

 upstream timed out (110: Connection timed out) while connecting to upstream,

Does it happen to you too?

Note that I'm not using the userId, nor Cloudflare.

Regards,
Benoit

Nevermind, I found the answer.

For some reason, IPv6 is not working correctly on my box.
Nginx timed out when it used the IPv6 address of www.google-analytics.com.

The solution was to add the following line to the server block:

resolver 8.8.8.8 ipv6=off;

And wait a long time (I would say 10m) until the cache expires.

I found a mistake in the NGINX configuration shown at the top.
It should not be:

proxy_pass http://www.google-analytics.com/;

but it should be:

proxy_pass http://www.google-analytics.com;

It's crucial to remove the trailing slash; otherwise, NGINX drops all the query parameters.

Some adblockers are strict and even block urls like '/r/collect/'
Sot he trick is to replace sub_filter 'r/collect' 'rrr/upstreamer';
then add a block of code

location /rrr/upstreamer/{
        proxy_set_header Accept-Encoding "";
        sub_filter 'www.google-analytics.com'  'subcode.example.com';
        sub_filter_types *;
        sub_filter_once off;
        proxy_pass https://www.google-analytics.com/r/collect;
        break;
    }