nginx proxy_pass by query param(query url) example

nginx_proxy_by_query.conf

events {
}

http {
    server {
        listen 80;
        server_name localhost;
        location / {
            set $host_1 "http://127.0.0.1:8881";
            set $host_2 "http://127.0.0.1:8882";
            set $cur_host "http://127.0.0.1:8888";
            if ($args ~* (.*)(channel=android)(.*)) {
                set $cur_host $host_1;
            }
            if ($args ~* (.*)(channel=ios)(.*)) {
                set $cur_host $host_2;
            }
            proxy_pass $cur_host;
        }
    }
}

daemon off;