Use Nginx to redirect www to subdomain under https

So I had a big struggle a few days ago when tring to organize the re-direct between different domain name of by blog. Essentially, I want everything to go through non-www https route ---- namely, https://blog.moelf.xyz

That means:

Doing the http -> https 301 redirect is super easy in nginx:

Simply have a server block in /etc/nginx/**.conf :

server{
    server_name moelf.xyz blog.moelf.xyz;
    listen 80;
    return 301 https://blog.moelf.xyz;
    #rest of your block;
}

will do the job. This basically means anything coming to port 80 on your server will get redirected to https non-www domain.

The https part is tricky: if you want your https non-www to be resolved normally, you will need SSL certificates for both non-www and www seperately (in my case blog.**.xyz) because the website is directing the browser from https to https.

server {
    server_name moelf.xyz blog.moelf.xyz;
    listen 80;
    return 301 https://blog.moelf.xyz/;

}
server {
    listen 443 ssl;
    server_name moelf.xyz;
    return 301 https://blog.moelf.xyz/;
    ssl_certificate ***/fullchain.pem;
    ssl_certificate_key ***/moelf.xyz/privkey.pem;
    #other_stuff_in_the_block
}

server {
    server_name blog.moelf.xyz; # Replace with your domain
    listen 443 ssl;
    access_log /var/log/nginx/www_ss.log;
    ssl_certificate ***/blog.moelf.xyz/fullchain.pem;
    ssl_certificate_key ***/blog.moelf.xyz/privkey.pem;
    #other_stuff_in_the_block

}

In the above code, the second block is used to redirect non-www visit and the third server block is used to handle everything.