QKnxNetIpConnectionStateRequestProxy Class

The QKnxNetIpConnectionStateRequestProxy class provides the means to read a KNXnet/IP connection state request from the generic QKnxNetIpFrame class and to create a connection state request frame based on the information. More...

Header: #include <QKnxNetIpConnectionStateRequestProxy>
qmake: QT += knx

Public Types

class Builder

Public Functions

QKnxNetIpConnectionStateRequestProxy(const QKnxNetIpFrame &frame)
quint8 channelId() const
QKnxNetIpHpai controlEndpoint() const
bool isValid() const

Static Public Members

QKnxNetIpConnectionStateRequestProxy::Builder builder()

Detailed Description

The QKnxNetIpConnectionStateRequestProxy class provides the means to read a KNXnet/IP connection state request from the generic QKnxNetIpFrame class and to create a connection state request frame based on the information.

Host protocols like UDP/IP that do not provide mechanisms for checking the lifetime of a connection need a way to tell when communication fails. To detect failures on the KNX or in the tunneling network, heartbeat monitoring is implemented by both KNXnet/IP clients and servers, as follows. A KNXnet/IP client sends a connection state request frame regularly to the KNXnet/IP server's control endpoint to check the state of a connection established to the server. The server responds immediately with a connection state response frame.

In most programs, this class will not be used directly. Instead, the QKnxNetIpTunnel or QKnxNetIpDeviceManagement class is used to establish a functional connection to a KNXnet/IP server.

The following code sample illustrates how to read the connection state request information sent by a KNXnet/IP client:

auto frame = QKnxNetIpFrame::fromBytes(...);

const QKnxNetIpConnectionStateRequestProxy connectionStateRequest(netIpFrame);
if (!connectionStateRequest.isValid())
    return;

quint8 chanId = connectionStateRequest.channelId();
auto hpai = connectionStateRequest.controlEndpoint();

See also builder(), QKnxNetIpConnectionStateResponseProxy, and Qt KNXnet/IP Connection Classes.

Member Function Documentation

QKnxNetIpConnectionStateRequestProxy::QKnxNetIpConnectionStateRequestProxy(const QKnxNetIpFrame &frame)

Constructs a wrapper object to read the connection state request information carried by the specified KNXnet/IP frame frame.

[static] QKnxNetIpConnectionStateRequestProxy::Builder QKnxNetIpConnectionStateRequestProxy::builder()

Returns a builder object to create a KNXnet/IP connection state request frame.

quint8 QKnxNetIpConnectionStateRequestProxy::channelId() const

Returns the ID of the communication channel prepared by the KNXnet/IP server.

QKnxNetIpHpai QKnxNetIpConnectionStateRequestProxy::controlEndpoint() const

Returns the control endpoint of the KNXnet/IP client sending the connection state request.

bool QKnxNetIpConnectionStateRequestProxy::isValid() const

Returns true if the frame contains initialized values and is in itself valid, otherwise returns false. A valid KNXnet/IP frame consists of at least a valid header and a size in bytes corresponding to the total size of the KNXnet/IP frame header.

See also QKnxNetIpFrameHeader::totalSize().

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