location ~* ^/upload/.+\.(png|jpg|gif|pdf|log)$ {
        root $Rootpath;
        expires max;
        add_header Cache-Control public;
        add_header Vary Accept-Encoding;
        proxy_cache czone;
        proxy_cache_valid 200 20m;
        proxy_set_header Host $CacheHost;
        proxy_pass http://127.0.0.1:88;
    }