events/server_events.cpp

#include <open62541pp/event.hpp>
#include <open62541pp/node.hpp>
#include <open62541pp/server.hpp>
 
int main() {
    opcua::Server server;
 
    // Objects node can be used to subscribe to events.
    opcua::Node objectsNode(server, opcua::ObjectId::ObjectsFolder);
    objectsNode.writeEventNotifier(opcua::EventNotifier::SubscribeToEvents);
 
    // Add a method to generate and trigger events.
    opcua::Event event(server);
    objectsNode.addMethod(
        {1, 1000},
        "GenerateEvent",
        [&](opcua::Span<const opcua::Variant> input, opcua::Span<opcua::Variant>) {
            const auto severity = input.at(0).scalar<uint16_t>();
            const auto& message = input.at(1).scalar<opcua::String>();
 
            event.writeTime(opcua::DateTime::now());
            event.writeSeverity(severity);
            event.writeMessage({"", message});
            event.trigger();
        },
        {
            {"severity", {"", "Severity"}, opcua::DataTypeId::UInt16, opcua::ValueRank::Scalar},
            {"message", {"", "Message"}, opcua::DataTypeId::String, opcua::ValueRank::Scalar},
        },
        {}
    );
 
    server.run();
}