Proxying cross domain requests through nginx unified config?

Question

Nginx

There is a config for nginx.
The task is to proxy cross-domain ajax requests through your server.

server {

    listen   80;
    server_name  domain.com;

    access_log  /var/log/nginx/domain.access.log main;
    error_log  /var/log/nginx/domain.error.log info;

    root /var/www;

    location ~* ^.*\/proxy\/(?<pschema>.*)?\/(?<phost>.*)?\/.*$ {
        set $adr $pschema://$phost;

        rewrite ^.*\/proxy\/.*?\/.*?(\/.*)$ $1 break;

        proxy_pass http://domain1.com;
#       если вот так то не работает
#       proxy_pass $adr;

        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Host $phost;
        proxy_set_header X-NginX-Proxy true;
        proxy_redirect off;
        proxy_connect_timeout 1;
        proxy_intercept_errors on;
        expires 30;
        break;
    }

    location / {
        index index.html index.htm;
    }

    location ~* \.(jpg|ico|gif|png|css|js|svg)$ {
        access_log off;
        expires 30d;
    }
}

it seems to work if you explicitly indicate which host to do proxy_pass, and when a variable is passed to proxy_pass, it does not want to work.

proxy_pass http://domain1.com;
# если вот так то не работает
# proxy_pass $adr;

How to solve the problem so that for each new necessary domain you do not write your own location?
UPD: Config that solves the problem

server {

    listen   80;
    server_name  domain.com;

    access_log  /var/log/nginx/domain.access.log main;
    error_log  /var/log/nginx/domain.error.log info;

    root /var/www;

    location ~* ^.*\/proxy\/(?<pschema>.*)?\/(?<phost>.*)?\/.*$ {
        resolver $dns_from_your_interfaces;
        #если есть свой dns на 127.0.0.1 то можно прописать его

        set $adr $pschema://$phost;

        rewrite ^.*\/proxy\/.*?\/.*?(\/.*)$ $1 break;

        proxy_pass $adr;

        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Host $phost;
        proxy_set_header X-NginX-Proxy true;
        proxy_redirect off;
        proxy_connect_timeout 1;
        proxy_intercept_errors on;
        expires 30;
        break;
    }

    location / {
        index index.html index.htm;
    }

    location ~* \.(jpg|ico|gif|png|css|js|svg)$ {
        access_log off;
        expires 30d;
    }
}

Answer 1

Try to specify the scheme
And see if you made the correct regular expressions.
And what kind of request do you have?