Multiple Dynamic Domains Using ONE Codeigniter Installation - codeigniter

Question

One of my jobs is to manage 58 sites for properties spread out across the country. They each have their own domain and are all housed in the same Dedicated Virtual Serve at Media Temple. The sites which are about 19 pages each use the exact same html/css/php code. The images are served to each site from a central repository living in different folders for each theme used.
What I want to do is to install one single installation of CI2 including the application folder because everything that is different between the sites is stored in the database. As long as I can give the controller a unique property number (which I would hope I could do when they access the index.php page in each domain), then all of my sites will work fine.
In all the answers I have read, the suggestion is to replicate the application folders and just reuse the core. What would work best for me is to also reuse the application folder. Then when I make a modification, it will cascade to all sites without me having to touch 58 pages.
Is this possible?

Answer 1

If all files are the same and the only thing changing between apps is the data from the database, then you can do this:
Point all domains to your docroot for the CI install
in your index.php, determine which db connection you need to use for the currently requested domain:
// index.php
$domain = $_SERVER['SERVER_NAME'];
switch ($domain)
{
case 'www.firstsite.com':
$this->load->database('firstsitedb');
break;
case 'www.secondsite.com':
$this->load->database('secondsitedb');
break;
default:
show_error('No Site Found');
break;
}
** OR **
If they each use the same database, and you need to be able to use a variable in your queries, then just set a constant based on the switch/case instead of loading a different database. Then you can use that constant throughout your application in your queries.
// index.php
$domain = $_SERVER['SERVER_NAME'];
$site_id = 0; // default
switch ($domain)
{
case 'www.firstsite.com':
$site_id = 1;
break;
case 'www.secondsite.com':
$site_id = 2;
break;
default:
show_error('No Site Found');
break;
}
define('SITE_ID', $site_id);

Answer 2

With Codeigniter 2.2, the index.php now allows the setting of a config array item (the feature is documented in that file). So it is possible to save the requested domain as a site variable in effect by doing this:
$assign_to_config['site_domain'] = empty($_SERVER['SERVER_NAME']) ? 'default.dev' : $_SERVER['SERVER_NAME'];
Later you could match this site_domain string against a database look-up to fetch the requisite content & theme views etc.