Correct way in new versions of nginx

Turn out my first answer to this question was correct at certain time, but it turned into another pitfall - to stay up to date please check Taxing rewrite pitfalls

I have been corrected by many SE users, so the credit goes to them, but more importantly, here is the correct code:

server {
       listen         80;
       server_name    my.domain.com;
       return         301 https://$server_name$request_uri;
}

server {
       listen         443 ssl;
       server_name    my.domain.com;
       # add Strict-Transport-Security to prevent man in the middle attacks
       add_header Strict-Transport-Security "max-age=31536000" always; 

       [....]
}

According to nginx pitfalls, it's slightly better to omit the unnecessary capture, using $request_uri instead. In that case, append a question mark to prevent nginx from doubling any query args.

server {
    listen      80;
    server_name signup.mysite.com;
    rewrite     ^   https://$server_name$request_uri? permanent;
}