method/server_method.cpp

#include <algorithm>
 
#include <open62541pp/node.hpp>
#include <open62541pp/server.hpp>
 
int main() {
    opcua::Server server;
 
    opcua::Node objectsNode(server, opcua::ObjectId::ObjectsFolder);
 
    // Add a method to return "Hello " + provided name.
    objectsNode.addMethod(
        {1, 1000},
        "Greet",
        [](opcua::Span<const opcua::Variant> input, opcua::Span<opcua::Variant> output) {
            const auto& name = input.at(0).scalar<opcua::String>();
            const auto greeting = std::string("Hello ").append(name);
            output.at(0) = greeting;
        },
        {{"name", {"en-US", "your name"}, opcua::DataTypeId::String, opcua::ValueRank::Scalar}},
        {{"greeting", {"en-US", "greeting"}, opcua::DataTypeId::String, opcua::ValueRank::Scalar}}
    );
 
    // Add a method that takes an array of 5 integers and a scalar as input.
    // It returns a copy of the array with every entry increased by the scalar.
    objectsNode.addMethod(
        {1, 1001},
        "IncInt32ArrayValues",
        [](opcua::Span<const opcua::Variant> input, opcua::Span<opcua::Variant> output) {
            const auto values = input.at(0).array<int32_t>();
            const auto delta = input.at(0).scalar<int32_t>();
            std::vector<int32_t> incremented(values.size());
            std::transform(values.begin(), values.end(), incremented.begin(), [&](auto v) {
                return v + delta;
            });
            output.at(0) = incremented;
        },
        {
            opcua::Argument(
                "int32 array",
                {"en-US", "int32[5] array"},
                opcua::DataTypeId::Int32,
                opcua::ValueRank::OneDimension,
                {5}
            ),
            opcua::Argument(
                "int32 delta",
                {"en-US", "int32 delta"},
                opcua::DataTypeId::Int32,
                opcua::ValueRank::Scalar
            ),
        },
        {
            opcua::Argument(
                "each entry is incremented by the delta",
                {"en-US", "int32[5] array"},
                opcua::DataTypeId::Int32,
                opcua::ValueRank::OneDimension,
                {5}
            ),
        }
    );
 
    server.run();
}