public function getReferer()
    {
        $referer = null;

        if (array_key_exists(self::REFERER_KEY, $this->serverData)) {
            $referer = $this->serverData[self::REFERER_KEY];
        }

        return $referer;
    }
public function getReferer()
    {
        $referer = null;

        if (array_key_exists(self::REFERER_KEY, $this->serverData)) {
            $referer = $this->serverData[self::REFERER_KEY];
        }

        return $referer;
    }
public function getReferer ( ) { $ referer = null ; if ( array_key_exists ( self :: REFERER_KEY , $ this -> serverData ) ) { $ referer = $ this -> serverData [ self :: REFERER_KEY ] ; } return $ referer ; }
Get the HTTP REFERER from the server data.

@return string|null The referer or null if not found.
Get the HTTP REFERER from the server data .