Piwik\Plugins\CustomVariables\CustomVariables::extendVisitorDetails PHP Method

    public function extendVisitorDetails(&$visitor, $details)
    {
        $customVariables = array();
        $maxCustomVariables = self::getNumUsableCustomVariables();
        for ($i = 1; $i <= $maxCustomVariables; $i++) {
            if (!empty($details['custom_var_k' . $i])) {
                $customVariables[$i] = array('customVariableName' . $i => $details['custom_var_k' . $i], 'customVariableValue' . $i => $details['custom_var_v' . $i]);
            }
        }
        $visitor['customVariables'] = $customVariables;
    }