Dynamic sub-domains with PHP

[niroshan]

Hi Guys,

I have to create sub-domains dynamically by php when a user registered in my site. Basically what I want is to create a personal site for the people who signup with me and give them the ability to access it through username.domain.com.

I did some searching and, I found out that we can do this by writing an entry in the apache http.conf as "ServerAlias *.domain.com".

So according to that article, what that will do is, apache will search what ever the folder we typed as sub-domain in the server.

Ex: test.test.com will search the folder as test.com/test

Then we can have to have a .htaccess file which will catch 404 error (folder not exists) and redirect it to desired place.

Is this can be done? I’m using a third party hosting so I have to be 100% sure about this before approaching them. Does this work? Anybody have a better idea?

I really appreciate all your help.

Thanx,

Regards,
Niroshan

[leatherback]

I think I would use a mod-rewrite on your domains, and let apache handle the rewrite:

You have URL
person.domain.come
Have apage rewrite that to:
domain.com/user

rewriteCond %{HTTP_HOST} ^{(.).domain.com$}
rewriteRule ^.$ http://www.domain.com/%1

Make sure you add a condition that your real subdomains do not get rewritten that way.

[MarkR]

You could do it entirely in PHP by examining $_SERVER['HTTP_HOST'].

1. Set up a wild card DNS for all subdomains to point to the right address
2. Set up a wild card virtual host in Apache, so that that virtual host matches all the domains you want (Ensure that other vhosts still work)
3. Write some code which examines $_SERVER['HTTP_HOST'] and behaves accordingly; if you find a nonexistent host, just throw back a 404

Testing this on your dev server could be nontrivial; I recommend judicious use of a "hosts" file to simulate the production server's DNS setup.

Also ensure that your Apache config is going to do what you want - again, testing with a HOSTS file with many entries should enable you to try it out in a non-production environment.

Mark

[niroshan]

Hi guys,

Thank you very much for valuable replies.. Really appreciate it.

I kind of don’t have permission to the server so I end up doing things in PHP.

I have a small problem. I will briefly explain my situation.

I checked the sub-domain using $_SERVER['HTTP_HOST'] and then validated that against my database values. If the value does not exist then Ii displayed the normal index page where as if the value exists I register a session and wanted to generate a PHP 404 error.

I have an .htaccess file in my root that catches all the 404 errors and redirect every call to a specific file.

I’m using a .htaccess file because I don’t want to change the URL that user typed since I wanted to feel them, that they are in a sub domain.(but actually they are not)

But the problem is even though I have generated the 404 error the .htaccess file won’t pick it up.

This is how I did it,

$domainname='';
$subdomainname='';

$domainarray = explode('.', $_SERVER['HTTP_HOST']);
$index=count($domainarray)-1;
$domainname= $domainarray[$index-1].".".$domainarray[$index];
for($i=0;$i<$index-1;$i++)
{
	if($subdomainname=="")
	{
		$subdomainname=$domainarray[$i];
	}
	else
	{
		$subdomainname=$subdomainname.".".$domainarray[$i];
	}
} 

if($subdomainname<>'')
{
	$sql = "SELECT id FROM tablename WHERE screenName='".$subdomainname."'";	
	$row = mysql_query($sql) or die ("Error checking screen name");
	if(mysql_num_rows($row)<>0)
	{
		$result = mysql_fetch_array($row) or die ("Error getting screen name");
		$_SESSION['bpId']=$result['id'];
		$templateBPId=$result['id'];
		header("HTTP/1.1 404 Not Found");		
		die();		
	}
}

What I’m doing wrong here?

Thanks,
Niroshan