Using $this inside a static function fails

This is the correct way

public static function userNameAvailibility()
{
     $result = self::getsomthin();
}

Use self:: instead of $this-> for static methods.

See: PHP Static Methods Tutorial for more info :)

You can't use $this inside a static function, because static functions are independent of any instantiated object. Try making the function not static.

Edit: By definition, static methods can be called without any instantiated object, and thus there is no meaningful use of $this inside a static method.

Only static functions can be called within the static function using self:: if your class contains non static function which you want to use then you can declare the instance of the same class and use it.

<?php
class some_class{
function nonStatic() {
    //.....  Some code ....   
    }
 Static function isStatic(){
    $someClassObject = new some_class;
    $someClassObject->nonStatic();
    } 
}
?>