How to make multiple domains on one engine?

Question

CMS

Some CMS have the function "several sites on one copy of the system" it is natural that in this case all of them work on one database.
How is redirection done within the system? If site1.ru is driven in, then one main page and the template should be shown if site2.ru, then another one is obtained.
What can I read on this topic, what kind of search queries should I enter in order to find such information?

Answer 1

Yes, everything is elementary here, Watson! Look in $_SERVER and see the site name in the value under the HTTP_HOST index.
Well, then it's a matter of technology. Design your system taking into account the existence of the domain entity, naturally, store a list of bound domains inside the system and, if the domain is outside this list, redirect to the default one or show the "Domain not found" page.
For each separate domain, a separate tree is made in the file storage and templates.
In a page tree plan, the top level would be a list of domains.
With users, the situation is a little more interesting, because. they can be identified in different ways.
Usually make a composite key between the domain and mail.

Answer 2

read about http referer, sessions and redirects apparently.