src/Request.php
public function getReferrer()
    {
        if (isset($this->_referrer)) {
            return $this->_referrer;
        }
        return $this->_referrer = isset($_SERVER['HTTP_REFERER']) ? $_SERVER['HTTP_REFERER'] : null;
    }
public function getReferrer()
    {
        if (isset($this->_referrer)) {
            return $this->_referrer;
        }
        return $this->_referrer = isset($_SERVER['HTTP_REFERER']) ? $_SERVER['HTTP_REFERER'] : null;
    }
public function getReferrer ( ) { if ( isset ( $ this -> _referrer ) ) { return $ this -> _referrer ; } return $ this -> _referrer = isset ( $ _SERVER [ 'HTTP_REFERER' ] ) ? $ _SERVER [ 'HTTP_REFERER' ] : null ; }
Returns the URL referrer, null if not present.

@return string URL referrer, null if not present
Returns the URL referrer null if not present .