Custom nginx vhost template

Hi, could you help me - I want to add http >> https redirect to my custom vhost.

I already tested successfully with current vhost (but it will be overwriten by ispconfig). I add this to the first line of current vhost:

Code:

server {
               listen 1.2.3.4;
               server_name domain.tld www.domain.tld;
               return 301 https://domain.tld$request_uri;
}

So based on above code I want to add that line to custom nginx_vhost.conf.master. But Is it allowed to have 2 'if ssl_enabled' ?
Is this template below is correct ?

Code:

<tmpl_if name='ssl_enabled'>
server {
  listen  ip_address;
       server_name <tmpl_var name='domain'> <tmpl_var name='alias'>;
       return 301 https://<tmpl_var name='domain'>$request_uri;
}
</tmpl_if>

server {
  listen <tmpl_var name='ip_address'>:80;
<tmpl_if name='ipv6_enabled'>
  listen [<tmpl_var name='ipv6_address'>]:80;
</tmpl_if>

<tmpl_if name='ssl_enabled'>
  listen <tmpl_var name='ip_address'>:443 ssl;
  ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
..................

 

Thanks TIll. Your solution works great.

But may I know why we should not add another server directive in nginx vhost ?