How to access dynamic global information in a static function

I'm setting some global configuration variables in the following manner:

$yaml = file_exists('config.yml') ? Spyc::YAMLLoad('config.yml') : array();

$defaults = array(
  'hostname' => 'localhost',
  'base_uri' => '/wag/'
);

$config = array_merge($default, $yaml);

Now I'd like to define a function base_url($https) that returns a base URL. The method body might just be:

return 'http' . ($https ? 's' : '') . '//' . $config['hostname'] . $config['base_uri'];

But I don't know how to access those default variables after they have been created. How would I go about doing so. I'd also be open to finding another way to achieve the end goal I'm looking for (having a configuration variable/constant as well as some utility fu开发者_开发技巧nctions to help me synthesize values based on that configuration data).

Create a config class, define class variables and use get/set methods to store and retrieve the params.

Example:

class Config
{
    private $_hostname = "localhost";
    private $_baseUri;

    public function __construct($_hostname, $baseUri)
    {
        //initialise vars
    }

    public function getHostname()
    {
        return $this->_hostName;
    }

    public function setHostname($hostName)
    {
        $this->_hostName = $hostName;
    }
}