PayPal\Ipn\PPIPNMessage::setEndpoint PHP Method

    private function setEndpoint()
    {
        if (isset($this->config['service.EndPoint.IPN'])) {
            $url = $this->config['service.EndPoint.IPN'];
        } else {
            if (isset($this->config['mode'])) {
                if (strtoupper($this->config['mode']) == 'SANDBOX') {
                    $url = PPConstants::IPN_SANDBOX_ENDPOINT;
                } else {
                    if (strtoupper($this->config['mode']) == 'LIVE') {
                        $url = PPConstants::IPN_LIVE_ENDPOINT;
                    } else {
                        if (strtoupper($this->config['mode']) == 'TLS') {
                            $url = PPConstants::IPN_TLS_ENDPOINT;
                        } else {
                            throw new PPConfigurationException('mode should be LIVE, TLS or SANDBOX');
                        }
                    }
                }
            } else {
                throw new PPConfigurationException('You must set one of mode OR service.endpoint.IPN parameters');
            }
        }
        return $url;
    }