nginx服务器http重定向到https的正确写法

参考文章：https://www.nginx.com/resources/wiki/start/topics/tutorials/config_pitfalls/#taxing-rewrites
最新的写法:

server {
    listen 80;
    server_name xxx.abc.com;
    return 301 https://$server_name$request_uri;
}
server {
    listen    443;
    server_name    xxx.abc.com;
}