When you open up app/Mage.php, you’ll see that the class declaration of Mage is final. The ‘final’ keyword prevents this class from being overridden. And you’ll see that every function is a magento static function, for example: public static function getVersion(). A static function means that you do not need to instantiate the class to use the method.
I will listed out some of most useful methods available here. If you want to see all other methods, just open up app/Mage.php file and have a look. You can call these anywhere within your application:
Mage::getVersion();
It will return your current Magento version.
Mage::getModel($modelClass = '', $arguments = array());
It returns a new model object.
Mage::app();
It will Initialize a Magento application object.
Mage::getBaseUrl($type = Mage_Core_Model_Store::URL_TYPE_LINK, $secure = null);
Returns the base URL by type.
Mage::register($key, $value);
It registers a new variable in the registry.
Mage::unregister($key);
It unregisters a variable in the registry.
Mage::registry($key);
It returns a value from the registry by the given key.
Mage::getBaseDir($type = 'base');
It returns the root absolute path.
Mage::getModuleDir($type, $moduleName);
It returns absolute path of a given module.
Mage::getConfig();
Returns a config instance.
Mage::getUrl($route = '', $params = array());
It generates a url by route and parameters.
Mage::getStoreConfigFlag($path, $store = null);
It returns a config flag by path.
Mage::dispatchEvent($name, array $data = array());
Dispatches an event in Magento.
Mage::getSingleton($modelClass = '', $arguments = array());
It returns a model object singleton.
Mage::getResourceModel($modelClass, $arguments = array());
it returns a resource model object.
Mage::throwException($message, $messageStorage = null);
Throw an exception in Magento way.
Mage::helper($name);
it returns a helper object.
Mage::log($message, $level = null, $file = '', $forceLog = false);
It’s a logging tool. If you only pass a message, it logs to var/log/system.log, if you have logging enabled.
