Rewrite "https://files.mydomain.com/files" to "https://files.mydomain.com"

Currently, I am able to visit: https://files.mydomain.com/files. Even if I go to https://files.mydomain.com, it will redirect automatically to https://files.mydomain.com/files successfully.

Instead, I would like for NGINX to automatically rewrite https://files.mydomain.com/files -> https://files.mydomain.com

My current NGINX code:

<!-- begin snippet: js hide: false console: true babel: false -->

<!-- language: lang-properties -->

http {

    server {
        
            listen       80;
            server_name  localhost;
            return 301 https://$host$request_uri;
    }

    server {

            listen       80;
            server_name  files.mydomain.com;
            location / {
                return 301 https://files.mydomain.com$request_uri;
        }
    }

    server {
            listen 443 ssl http2; 
            listen [::]:443 ssl http2;
            server_name  files.mydomain.com;
            client_max_body_size 0;
            location / {
                return 301 https://$host/files;
            } 
            location /files {
                proxy_pass http://localhost:89;
            }
    }

    #Root Domain
    server {
            listen 443 ssl http2; 
            listen [::]:443 ssl http2;
            server_name_in_redirect off;
            server_name  www.mydomain.com mydomain.com;
            log_not_found off;

        location / {
            root   /inetpub/wwwroot;
            index  index.html index.htm;
        }
    }
}

<!-- end snippet -->

My best attempt:
Unfortunately, it just takes me to the "Welcome to NGINX" webpage when I visit:
https://files.mydomain.com

<!-- begin snippet: js hide: false console: true babel: false -->

<!-- language: lang-properties -->

http {

    server {
        
            listen       80;
            server_name  localhost;
            return 301 https://$host$request_uri;
    }

    server {

            listen       80;
            server_name  files.mydomain.com;
            location / {
                return 301 https://files.mydomain.com$request_uri;
        }
    }

    server {
            listen 443 ssl http2; 
            listen [::]:443 ssl http2;
            server_name  files.mydomain.com;
            client_max_body_size 0;
            location ^~ /files {
                rewrite ^/files/?(.*)$ https://files.mydomain.com/$1 permanent;
                proxy_pass http://localhost:89/files;
            }
    }

    #Root Domain
    server {
            listen 443 ssl http2; 
            listen [::]:443 ssl http2;
            server_name_in_redirect off;
            server_name  www.mydomain.com mydomain.com;
            log_not_found off;

        location / {
            root   /inetpub/wwwroot;
            index  index.html index.htm;
        }
    }
}

<!-- end snippet -->

*** [Final answer] ***

After several tests, the following configuration covers almost all the prerequisites.

Both / and /files/ are forwarded to localhost:89/files/.

server {
	listen 443 ssl;
	ssl_certificate .../fullchain.pem;
	ssl_certificate_key .../privkey.pem;

	server_name files.mydomain.com;

	location /files/ { 
	    proxy_pass http://localhost:89/files/;
	}       

	location / { 
	    proxy_pass http://localhost:89/files/;
	}
	proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
	proxy_set_header Host $host;
	proxy_http_version 1.1;
	proxy_set_header Upgrade $http_upgrade;
	proxy_set_header Connection "upgrade";
}

In this real case, only a small issue at first visit :

> When I visit https://files.mydomain.com for the first time, it
> automatically forwards to:
> https://files.mydomain.com/files/login.aspx. After I authenticate with
> my credentials, it automatically forwards to
> https://files.mydomain.com/files instead of
> https://files.mydomain.com. However the good news is if I stay logged
> in and revisit https://files.mydomain.com, it will continue to stay
> at: https://files.mydomain.com.

[Initial answer]

I know you are asking for url rewriting, but have you tried the proxy_pass+alias way?

My tests at home seem ok. I simply put files in a folder and use the following nginx configuration (I use port 8443 as a fake SSL port):

server {
	listen 8443;
	server_name files.ssl.localhost;
	root D:/WEB;

	location / {
	    alias D:/WEB/secretfolder/files/;
	    autoindex on; # or not, only to test folder listing
	}

	location /files/ { #beware the trailing slash
	    proxy_pass http://files.ssl.localhost:8443/; #beware the trailing slash
	}
}

http://files.ssl.localhost:8443/files/ and http://files.ssl.localhost:8443 both point to the same directory listing:

and we can get, for example, the contents of file.txt:

I hope this approach matches your goals or makes sense for anyone else.

Try using a return and not a rewrite for a redirect. This should work:

location /path/to-your-page-name {
  return 301 /new-path/to-your-new-page-name;
}

So, if you want domains resolving to ~/files and assuming that root points to /inetpub/wwwroot do the following:

http {

server {        
        listen 80;
        server_name  localhost;
        return 301 https://$host$request_uri;
}

server {
        listen 80;
        server_name  files.mydomain.com;
        location / {
            return 301 https://files.mydomain.com$request_uri;
        }
}

server {
        listen 443 ssl http2; 
        listen [::]:443 ssl http2;
        server_name  files.mydomain.com;
        client_max_body_size 0;
        location / {
            return 301 https://files.mydomain.com/files;
        }
}

#Root Domain
server {
        listen 443 ssl http2; 
        listen [::]:443 ssl http2;
        server_name_in_redirect off;
        server_name  www.mydomain.com mydomain.com;
        log_not_found off;

    location / {
        #root   /inetpub/wwwroot;
        #index  index.html index.htm;
		   return 301 https://files.mydomain.com/files;
        }
    }
}

You might also have to set server_name_in_redirect on; depending on your configuration.

I hope this helps!