Automatic subdomains based on folders mod_vhost_alias

Question

I guess the mod_vhost_alias should give me this solution, but im not shure how to use it.
My goal is to have new folders in my root folder become a subdomain.
like this: folder: root/test
Gives: test.domain.com
Under Aliases it says "Aliases make folders on this server publicly accessible via URLs on this server"
Need to find out what to set in "type" and "Alias Path"
Any ideas?

Answer 1

Assuming your main site www.example.com is using the default directory path:
/library/webserver/documents
Create a virtual host (what Apple calls a "Site"), and specify the path to the files. 
Here, assuming that:
/library/webserver/documents/test
will be the files you want to serve for that test.example.com site.  Specify that as the path for the virtual host.
The whole "subdomain" stuff foo.example.com isn't central; it's a virtual host, just like www.example.com host.
Your web browser clients will have to have a www.example.com translation (as they likely already do) and a test.example.com DNS translation (and that's usually a DNS CNAME for the same host as www.example.com), as the name of the virtual host to be selected arrives from the browser client.
Aliases aren't related to this stuff.  They're a way to have two (or more) names resolve to one host ("site").  However.... Watch out for any wildcard (*) aliases that might be around.  Those * wildcards can sometimes be found in some configurations, and can cause confusing behavior with which sites get selected for an incoming request, until found and elimiated.