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EventFilter

概述​

OPC UA Part 4 §7.18 EventFilter:

  • select_clauses — 抓哪些字段
  • where_clause — 过滤条件 (V1 暂未实现, 留 NULL)

DarraUa_SimpleAttributeOperand 字段: type_definition_id / browse_path / attribute_id / index_range。

API​

typedef struct {
    char*  type_definition_id;
    char** browse_path;        // 字符串数组
    size_t browse_path_count;
    DarraUa_AttributeId attribute_id;
    char*  index_range;        // null 表全部
} DarraUa_SimpleAttributeOperand;

typedef struct {
    DarraUa_SimpleAttributeOperand* select_clauses;
    size_t select_count;
    char*  where_clause;       // V1: NULL
} DarraUa_EventFilter;
函数类别读写说明
DarraUa_Subscription_SubscribeEvents(sub, src_nid, filter, &out_ev)写写创建事件订阅 (filter 可为 NULL)

代码示例​

#include <opcua.h>

DarraUa_Session* ua;
DarraUa_Session_New("opc.tcp://localhost:4840", &ua);
DarraUa_Session_Connect(ua);

DarraUa_Subscription* sub;
DarraUa_Session_CreateSubscription(ua, 500.0, &sub);

// 构造 filter
const char* event_id_path[]    = { "EventId" };
const char* event_type_path[]  = { "EventType" };
const char* source_path[]      = { "SourceName" };
const char* time_path[]        = { "Time" };
const char* msg_path[]         = { "Message" };
const char* sev_path[]         = { "Severity" };
const char* cond_id_path[]     = { "ConditionId" };
const char* active_state_path[] = { "ActiveState", "Id" };

DarraUa_SimpleAttributeOperand selects[8] = {
    { "i=2041", (char**)event_id_path, 1, ATTR_VALUE, NULL },
    { "i=2041", (char**)event_type_path, 1, ATTR_VALUE, NULL },
    { "i=2041", (char**)source_path, 1, ATTR_VALUE, NULL },
    { "i=2041", (char**)time_path, 1, ATTR_VALUE, NULL },
    { "i=2041", (char**)msg_path, 1, ATTR_VALUE, NULL },
    { "i=2041", (char**)sev_path, 1, ATTR_VALUE, NULL },
    { "i=2782", (char**)cond_id_path, 1, ATTR_VALUE, NULL },
    { "i=2915", (char**)active_state_path, 2, ATTR_VALUE, NULL },
};

DarraUa_EventFilter filter = {
    .select_clauses = selects,
    .select_count = 8,
    .where_clause = NULL,
};

DarraUa_EventSubscription* ev;
DarraUa_Subscription_SubscribeEvents(sub, "i=2253", &filter, &ev);

void on_event(const DarraUa_EventArgs* e, void* ctx) {
    /* fields 顺序与 select_clauses 一致 */
    /* fields[0]=EventId, fields[5]=Severity, fields[6]=ConditionId ... */
}
DarraUa_EventSubscription_RegisterArrived(ev, on_event, NULL);

字段速查​

EventTypeBrowsePath含义
BaseEventType (i=2041)["EventId"]事件唯一 ID
BaseEventType["Severity"]严重度 1-1000
ConditionType (i=2782)["ConditionId"]条件 NodeId
AcknowledgeableConditionType (i=2881)["AckedState", "Id"]是否 Ack
AlarmConditionType (i=2915)["ActiveState", "Id"]是否激活

实现说明​

  • Stack 不支持自定义 SelectClauses 时回退默认 5 字段并推 Diagnostic Info 事件

最佳实践​

  • 显式列字段
  • 顺序对齐: fields[i] 顺序就是 select_clauses 顺序
  • 报警面板必抓 ConditionId

跨语言对照​

C#PythonJavaC++RustC
EventFilterEventFilterEventFilterEventFilterEventFilterDarraUa_EventFilter
SimpleAttributeOperandSimpleAttributeOperandSimpleAttributeOperandSimpleAttributeOperandSimpleAttributeOperandDarraUa_SimpleAttributeOperand

下一步​