title: Working with subdomains in Yii2
body: <p>What is the best way to get subdomain info (<em>http://<strong>s1</strong>.<strong>s2</strong>.site.com</em>)?</p>
  
  <p>And is there a quick way of creating an url with another subdomain<br>
  <em>http://<strong>s1</strong>.<strong>s2</strong>.site.com</em> => <em>http://<strong>s3</strong>.<strong>s4</strong>.site.com</em> ?</p>