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Session 会话 — darra::opcua::Session

Session 是 Client 主类, 一个实例对应一个 OPC UA Session. 所有访问 (Read / Write / Browse / Subscribe / Call / History) 都从这个对象出发. Move-only, 析构自动 Disconnect + 释放 native handle.

#include <darra/opcua/client.hpp>
using namespace darra::opcua;
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公共访问器​

类别属性类型访问说明
连接EndpointUrl()std::string const&R构造时指定的 endpoint URL
Config()ConnectionConfig const&R完整连接配置 (含 SecurityMode 等)
Handle()DarraUa_SessionHandleRC 层句柄 (内部用)
状态State()SessionStateR当前会话状态 (Disconnected / Connecting / Connected / Reconnecting / Closing / Failed)
IsConnected()boolR等价 State() == Connected
子对象Nodes()NodeCollection&RLazy Load 节点访问器
NamespacesRef()Namespaces&R命名空间表
Events()SessionEvents&R会话级事件 (字段式 std::function)
配置SetKeepAliveInterval(ms)voidWKeepAlive 心跳周期 (默认 10000 ms, 0 = 禁用)
AutoPublish() / SetAutoPublish(bool)boolRW启停后台 Publish 线程 (默认 true)

公共方法​

连接管理​

方法说明
Connect()建立连接 (Hello → SecureChannel → Session → Activate)
Disconnect()主动断开, 实例可重连
~Session()析构自动 Disconnect + 释放 handle (RAII)

心跳与发布​

方法说明
Publish(timeout_ms = 2000)手动触发一次 Publish (一般无需调用)
StartAutoPublish() / StopAutoPublish()启停后台 Publish 线程

读 / 写​

方法说明
Read(node_id, attr = AttributeId::Value)读单节点指定 Attribute
ReadMany(node_ids, attr)批量读 (单 Attribute)
Write(node_id, variant, attr = Value)写单节点

浏览​

方法说明
Browse(node_id, filter = Unspecified)单层浏览
BrowseMany(node_ids, filter)批量浏览
BrowseWithPaging(node_id, filter)含 ContinuationPoint 翻页支持
BrowseNext(continuation_point, release = false)续翻分页
TranslateBrowsePaths(paths)路径批量解析为 NodeId
Resolve(path)单条绝对路径解析
Resolve(start_node_id, path)单条相对路径解析
RegisterNodes(node_ids)注册临时高效 NodeId
UnregisterNodes(registered_ids)注销临时 NodeId

订阅​

方法说明
CreateSubscription(interval_ms = 500.0)创建数据订阅
SubscribeEvents(node_id = "", existing = nullptr)订阅事件 (报警 / 条件)
TransferSubscriptions(sub_ids, send_initial)跨 Session 迁移订阅

方法调用​

方法说明
Call(object_id, method_id, inputs)调用 OPC UA Method 节点

历史​

方法说明
ReadHistory(node_id, start_ft, end_ft, max_values = 0, return_bounds = false)读原始历史
ReadHistoryModified(...)读含修改记录的历史
ReadHistoryAtTime(...)读指定时间点的内插值
ReadHistoryProcessed(...)聚合 (Avg / Min / Max / TimeAverage / ...)
ReadHistoryEvents(...)读历史事件
UpdateHistory(...)Insert / Replace / Update / Remove 历史
DeleteHistoryRange(...)按时间段删除

控制​

方法说明
Cancel(request_handle)取消未完成请求

Move-only 语义​

Session s("opc.tcp://localhost:4840");
// Session s2 = s;            // 编译错误: copy ctor deleted
Session s2 = std::move(s);    // OK, s 此后失效

完整示例​

#include <darra/opcua/client.hpp>
#include <iostream>

using namespace darra::opcua;

int main() {
    Stack::Init();
    Session s("opc.tcp://localhost:4840");

    s.Events().on_connected = [](std::string const& url) {
        std::cout << "Connected to " << url << "\n";
    };
    s.Events().on_disconnected = [](std::string const& url, Status reason) {
        std::cout << "Disconnected from " << url
                  << " reason=0x" << std::hex << static_cast<uint32_t>(reason) << "\n";
    };

    s.Connect();

    // 读
    auto dv = s.Read("ns=2;s=Temperature");
    double t = 0; dv.Value().TryGetDouble(t);
    std::cout << "T = " << t << " degC\n";

    // 写
    Variant v; v.SetDouble(42.0);
    auto st = s.Write("ns=2;s=Setpoint", v);
    std::cout << "Write status = 0x" << std::hex << static_cast<uint32_t>(st) << "\n";

    // 订阅
    auto sub = s.CreateSubscription(500.0);
    sub.AddNode("ns=2;s=Counter", [](DataValue const& dv) {
        std::cout << dv.Value().AsString() << "\n";
    });

    // 方法
    std::vector<Variant> args;
    { Variant a; a.SetInt32(3); args.push_back(std::move(a)); }
    { Variant b; b.SetInt32(4); args.push_back(std::move(b)); }
    auto outs = s.Call("ns=2;s=Calc", "ns=2;s=Calc.Add", args);
    for (auto const& o : outs) {
        int32_t sum = 0; o.TryGetInt32(sum);
        std::cout << "sum = " << sum << "\n";
    }

    std::this_thread::sleep_for(std::chrono::minutes(1));
    Stack::Shutdown();
    return 0;
}

下一步​