QOpcUaGenericStructHandler Class

QOpcUaGenericStructHandler handler(opcuaClient);
handler.initialize();

QObject::connect(&handler, &QOpcUaGenericStructHandler::initializedChanged, [opcuaClient, &handler](bool initialized) {
    if (!initialized)
        return;

    auto node = opcuaClient->node("ns=4;i=3003"); // A custom struct test node in the open62541-testserver
    node->readValueAttribute();

    QObject::connect(node, &QOpcUaNode::attributeRead, [node, &handler](QOpcUa::NodeAttributes attr) {
        if (!attr.testFlag(QOpcUa::NodeAttribute::Value) || node->valueAttributeError() != QOpcUa::UaStatusCode::Good)
            return;

        auto extObj = node->valueAttribute().value<QOpcUaExtensionObject>();
        qDebug() << "Got object of type" << handler.typeNameForBinaryEncodingId(extObj.encodingTypeId());

        const auto result = handler.decode(extObj);

        if (!result)
            return;

        qDebug() << *result;
    });
});

QOpcUaGenericStructHandler handler(opcuaClient);
handler.initialize();

QObject::connect(&handler, &QOpcUaGenericStructHandler::initializedChanged, [opcuaClient, &handler](bool initialized) {
    if (!initialized)
        return;

    QOpcUaGenericStructValue value = handler.createGenericStructValueForTypeId("ns=4;i=3006");
    value.fieldsRef()["MandatoryMember"] = 23.0;
    value.fieldsRef()["OptionalMember"] = 42.0;

    const auto ext = handler.encode(value);

    if (!ext)
        return;

    // Use the extension object to write a node's value attribute, in a method parameter, etc...
});

Member Function Documentation

[explicit] QOpcUaGenericStructHandler::QOpcUaGenericStructHandler(QOpcUaClient *client, QObject *parent = nullptr)

Constructs a generic struct handler for client.

bool QOpcUaGenericStructHandler::addCustomEnumDefinition(const QOpcUaEnumDefinition &definition, const QString &typeId, const QString &name, QOpcUa::IsAbstract isAbstract = QOpcUa::IsAbstract::NotAbstract)

Adds the custom enum definition definition to the known types. This can be used to support custom structures the server doesn't expose a StructureDefinition for. The parameters definition, typeId and name are required for proper decoding and encoding. If isAbstract is set, the type can't be encoded and decoded.

Returns true if the enum definition was successfully added.

bool QOpcUaGenericStructHandler::addCustomStructureDefinition(const QOpcUaStructureDefinition &definition, const QString &typeId, const QString &name, QOpcUa::IsAbstract isAbstract = QOpcUa::IsAbstract::NotAbstract)

Adds the custom structure definition definition to the known types. This can be used to support custom structures the server doesn't expose a StructureDefinition for. The parameters definition, typeId and name are required for proper decoding and encoding. If isAbstract is set, the type can't be encoded and decoded.

Returns true if the structure definition was successfully added.

QOpcUaGenericStructValue QOpcUaGenericStructHandler::createGenericStructValueForTypeId(const QString &typeId)

Returns a generic struct value pre-filled with the struct definition, type id and type name corresponding to typeId. For all mandatory fields, an invalid placeholder QVariant will be inserted.

QOpcUaGenericStructHandler::DataTypeKind QOpcUaGenericStructHandler::dataTypeKindForTypeId(const QString &id) const

Returns the data type kind for the type node id id.

std::optional<QOpcUaGenericStructValue> QOpcUaGenericStructHandler::decode(const QOpcUaExtensionObject &extensionObject) const

Decodes extensionObject to a QOpcUaGenericStructValue. If the decoder fails, std::nullopt is returned.

std::optional<QOpcUaExtensionObject> QOpcUaGenericStructHandler::encode(const QOpcUaGenericStructValue &value)

Returns value encoded as a QOpcUaExtensionObject, or std::nullopt if the value could not be encoded.

QOpcUaEnumDefinition QOpcUaGenericStructHandler::enumDefinitionForTypeId(const QString &id) const

Returns the QOpcUaEnumDefinition for the type node id id. If the node id is unknown or does not belong to an enum type, a default constructed value is returned.

bool QOpcUaGenericStructHandler::initialize()

Starts the data type hierarchy traversal. Success or failure is reported in the initializedChanged signal.

Returns false if the operation can't be started.

[since 6.7] bool QOpcUaGenericStructHandler::initialized() const

Returns true if the generic struct handler is initialized.

This function was introduced in Qt 6.7.

[signal] void QOpcUaGenericStructHandler::initializedChanged(bool initialized)

This signal is emitted when the initialization process has finished. initialized indicates if the initialization was successful.

bool QOpcUaGenericStructHandler::isAbstractTypeId(const QString &id) const

Returns true if the data type described by id is abstract.

QOpcUaStructureDefinition QOpcUaGenericStructHandler::structureDefinitionForBinaryEncodingId(const QString &id) const

Returns the QOpcUaStructureDefinition for the binary encoding node id id. If the node id is unknown or does not belong to a struct type, a default constructed value is returned.

QOpcUaStructureDefinition QOpcUaGenericStructHandler::structureDefinitionForTypeId(const QString &id) const

Returns the QOpcUaStructureDefinition for the type node id id. If the node id is unknown or does not belong to a struct type, a default constructed value is returned.

QString QOpcUaGenericStructHandler::typeIdForBinaryEncodingId(const QString &id) const

Returns the type node id associated with the binary encoding id id.

QString QOpcUaGenericStructHandler::typeNameForBinaryEncodingId(const QString &id) const

Returns the type name belonging to the binary encoding node id id. If the node id is unknown or does not belong to a struct type, an empty string is returned.

QString QOpcUaGenericStructHandler::typeNameForTypeId(const QString &id) const

Returns the type name belonging to a data type node identified by type node id id. If the node id is unknown, an empty string is returned.