nginx 代理 proxy_pass设置

#img.test.com/img1 实际访问的路径是  http://127.0.0.1:123/a1

#img.test.com/img2 实际访问的路径是  http://127.0.0.1:123/a2

 location / {
                proxy_set_header Host img.test.com;
                rewrite img1/(.+)$  /a1/$  break;
                rewrite img2/(.+)$  /a2/$  break;

                proxy_pass http://127.0.0.1:123/;#代理ip:127.0.0.1,端口123
                proxy_redirect off;
                proxy_set_header X-Real-IP $remote_addr;
                proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        }

上面是nginx的网站根目录,如果换成 /test_dir/,