Regional subdomains - php

Question

I want to make some regional subdomains of my current site.com - something like city1.site.com and city2.site.com, but I don't want to copy all the files from original domain to subdomain.
Is it possible to show on subdomain city1.site.com the same info as on site.com but just set one variable, something like $city = 123? With this variable on city1.site.com I can show more specific contacts and products for this city.
I'm new to subdomain so please help, my site is on PHP & MySQL. Thank you!

Answer 1

If you have few regions, you can manually create subdomains for each region and point the domains to the same folder as your main site. Then in your script you grab the host and match it to regions and assign desired value to a variable.
<?php
if($_SERVER['HTTP_HOST'] === 'city1.site.com') {
$city = 123;
} else if($_SERVER['HTTP_HOST'] === 'city2.site.com') {
$city = 223;
}
If you have many regions and want a dynamic match, you can match any subdomain to your main site path and inside the script you can use a method to get the subdomain and search in your database. Example:
<?php
$subdomain = strstr($_SERVER["HTTP_HOST"], '.', true);
$city = getRegion($subdomain);
if(!$city) {
// throw 404 error
header('HTTP/1.0 404 Not Found');
exit;
}
// getRegion($subdomain) is a method that should search your database to match the subdomain to a region
To match all subdomains to a path you need to use wildcard in CPanel. See tutorial: https://www.namecheap.com/support/knowledgebase/article.aspx/9191/29/how-to-create-a-wildcard-subdomain-in-cpanel

Answer 2

You can probably use the $_SERVER superglobals in php (read the docs: http://php.net/manual/en/reserved.variables.server.php especially the $_SERVER['HTTP_HOST']) to find out, which subdomain is the current one (if any)
The rest is probably easy, for example a switch statement depending on the current subdomain like
switch($_SERVER['HTTP_HOST']) {
case 'city1.site.com': $abc=1; break;
case 'city2.site.com': $abc=2; break;
default: $abc=0; break;
}
update: the idea is, to use the same code for all subdomains (you don't want to maintain an arbitrary amount of copies) and force different behaviour through code. perhaps you can even setup a "catchall" domain somehow.
So, if you setup your domain site.com to live in your server's htdocs/site.com directory, use the same directory for all the other domains as well.
To achieve different outputs for your sites, you then check the $abc variable or some other var (perhaps even $_SERVER['HTTP_HOST']) to do
if(strpos($_SERVER['HTTP_HOST'],'.site.com') !== FALSE) {
$subdomain = str_replace('.site.com','',$_SERVER['HTTP_HOST']);
}
else {
$subdomain = null;
}
// now 'city1' is in $subdomain
After you have extracted the subdomain, you can run sql queries or the like with that value (if your database is setup appropriately).

Answer 3

First step is to make sure your DNS records are ready. Add an A record for the following if it doesn't already exist.
EDIT - If you are using a shared host, this might not work properly END
Set the name part to '*' and then the next to value to the server IP address you currently use. Once this rule is in place, people can go to {anything}.site.com and will all be sent to the same server.
At this point, I would do something similar to Jakumi's answer but keep it simpler
/* Cut up the URL */
$hostDetails = explode('.', $_SERVER['HTTP_HOST']);
/* Get the first part (city) of the URL */
$city = current($hostDetails);
/* Default check */
if($city == 'site') { $city = 'YOUR_DEFAULT'; }