方式一,写死地址,用变量

最简洁

map $scheme $online_proxy_www {
default 39.156.66.10;
}

proxy_pass $scheme://$online_proxy_www:$server_port;

方式二,写两个upstream,再用proxy_pass覆盖法

缺点需要维护2个upsteam

upstream online_proxy_www {
server 39.156.66.10:80;
}
upstream online_proxy_www_https {
server 39.156.66.10:443;
}

proxy_pass $scheme://online_proxy_www;

自适应https

if ( $scheme = https) {
proxy_pass $scheme://online_proxy_www_https;
}

方式三,upstream backup法

最简单,缺点会多一次请求,多个错误日志

upstream online_proxy_www {
server 39.156.66.10:80;39.156.66.10
server 39.156.66.10:443 backup;
}
proxy_pass $scheme://online_proxy_www;

==========================

nginx.conf示例

upstream online_proxy_www {
    server   39.156.66.10:80;
    #server   39.156.66.10:443 backup;
}
upstream online_proxy_www_https {
    server   39.156.66.10:443;
}


server
{
    listen       80;
    listen       443 ssl;
    server_name  blog.c1gstudio.com;
    index index.html index.htm index.php;
    root  /opt/htdocs/www;
    access_log  /var/log/nginx/blog.c1gstudio.com.log  access ;

    include ssl.conf;

    location /
    {
        proxy_set_header Host  $host;
        proxy_set_header X-Forwarded-For $proxypass_forwarded_for;
        proxy_pass $scheme://$online_proxy_www:$server_port;

        add_header      X-Cache   C1GPROXY1;
    }


}