A singleton class to keep all settings for a site in one place.


class Settings {

    private static $singleton = null;
    private $settings = array();

    private function __construct() {
        $this->load();
    }

    public static function getInstance() {
        if(self::$singleton == null)
            self::$singleton = new Settings();
        return self::$singleton;
    }

    public function get($key) {
        if(substr($key, 20) == "site.url.currentpage") {
            return "$_SERVER[PHP_SELF]?$_SERVER[QUERY_STRING]";
        }else if(substr($key, 5) == "user.")
            return $_SESSION[$key];
        else
            return $this->settings[$key];
    }

    public function set($key, $value) {
        if(substr($key, 5) == "user.")
            $_SESSION[$key] = $value;
        else
            $this->settings[$key] = $value;
        $this->save();
    }

    public function load() {
        //populate settings array here;
        $this->settings["site.url"] = "http://whoyouknow.co.uk";
        $this->settings["site.url.index"] = $this->settings["site.url"] . "index.php";

        $this->settings["site.dir"] = "/public_html/whoyouknow.co.uk/";
        $this->settings["site.dir.index"] = $this->settings["site.dir"]  . "index.php";

        $this->settings["site.baseurl"] = 2;
    }

    public function save() {
        //save settings array here;
    }

    public function url($key, $params="") {
        $url = $this->get($key);

        if(!is_array($params)) { $params = func_get_args(); array_shift($params); }

        if(!strpos($url, "?") && count($params) > 0) $url .= "?";

        foreach($params as $param) {
            $url .= $param;
            if(++$i != count($params)) $url .= "&";
        }

        return $url;
    }

    public function urlVar($offset, $baseurl="") {
         $baseurl = either($baseurl, $this->get("site.baseurl"), 1);
         $url = explode("/", $_SERVER[REQUEST_URI]);
        return $url[$baseurl + $offset];
    }
}

echo Settings::getInstance()->get("site.url");
echo "<br />";
echo Settings::getInstance()->url("site.url", "id=23", "page=test");
echo "<br />";
echo Settings::getInstance()->urlVar(1);   //(url e.g. http://whoyouknow.co.uk/uni/settings.php/test/)
echo "<br />";
Settings::getInstance()->set("user.name", "James");
echo Settings::getInstance()->get("user.name");


Output

	http://whoyouknow.co.uk
	http://whoyouknow.co.uk?id=23&page=test
	test		
	James
	

Motives:

Keep all site settings in one place.
Provide user info and general settings from that one place.
Map URL key's to actual URLs to allow easy changing of URLs - no hardcoded URLs

Usage:

echo Settings::get($key);

Hierarchical key structure:

site.url http://whoyouknow.co.uk
site.url.index http://whoyouknow.co.uk/index.php
site.url.blog http://whoyouknow.co.uk/blog/
site.url.images http://whoyouknow.co.uk/images/

Corresponding dir/url keys:

site.dir /public_html/
site.dir.index /public_html/index.php
site.dir.blog /public_html/blog/
site.dir.images /public_html/images/

User info by same method - transparently uses sessions for user info

user.id
user.name
user.email etc

A url function:

Settings::url("site.url.blog", "id=1234", "user_id=25")
Settings::url("site.url.currentpage")

requires function: mixed either(mixed, mixed [, ..., ...])