/* This work is licensed under a Creative Commons CCZero 1.0 Universal License. * See http://creativecommons.org/publicdomain/zero/1.0/ for more information. */ /** * Working with Objects and Object Types * ------------------------------------- * * Using objects to structure information models * ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ * Assume a situation where we want to model a set of pumps and their runtime * state in an OPC UA information model. Of course, all pump representations * should follow the same basic structure, For example, we might have graphical * representation of pumps in a SCADA visualisation that shall be resuable for * all pumps. * * Following the object-oriented programming paradigm, every pump is represented * by an object with the following layout: * * .. graphviz:: * * digraph tree { * * fixedsize=true; * node [width=2, height=0, shape=box, fillcolor="#E5E5E5", concentrate=true] * * node_root [label=< ObjectNode
Pump >] * * { rank=same * point_1 [shape=point] * node_1 [label=< VariableNode
ManufacturerName >] } * node_root -> point_1 [arrowhead=none] * point_1 -> node_1 [label="hasComponent"] * * { rank=same * point_2 [shape=point] * node_2 [label=< VariableNode
ModelName >] } * point_1 -> point_2 [arrowhead=none] * point_2 -> node_2 [label="hasComponent"] * * { rank=same * point_4 [shape=point] * node_4 [label=< VariableNode
Status >] } * point_2 -> point_4 [arrowhead=none] * point_4 -> node_4 [label="hasComponent"] * * { rank=same * point_5 [shape=point] * node_5 [label=< VariableNode
MotorRPM >] } * point_4 -> point_5 [arrowhead=none] * point_5 -> node_5 [label="hasComponent"] * * } * * The following code manually defines a pump and its member variables. We omit * setting constraints on the variable values as this is not the focus of this * tutorial and was already covered. */ #include #include #include #include static void manuallyDefinePump(UA_Server *server) { UA_NodeId pumpId; /* get the nodeid assigned by the server */ UA_ObjectAttributes oAttr = UA_ObjectAttributes_default; oAttr.displayName = UA_LOCALIZEDTEXT("en-US", "Pump (Manual)"); UA_Server_addObjectNode(server, UA_NODEID_NULL, UA_NODEID_NUMERIC(0, UA_NS0ID_OBJECTSFOLDER), UA_NODEID_NUMERIC(0, UA_NS0ID_ORGANIZES), UA_QUALIFIEDNAME(1, "Pump (Manual)"), UA_NODEID_NUMERIC(0, UA_NS0ID_BASEOBJECTTYPE), oAttr, NULL, &pumpId); UA_VariableAttributes mnAttr = UA_VariableAttributes_default; UA_String manufacturerName = UA_STRING("Pump King Ltd."); UA_Variant_setScalar(&mnAttr.value, &manufacturerName, &UA_TYPES[UA_TYPES_STRING]); mnAttr.displayName = UA_LOCALIZEDTEXT("en-US", "ManufacturerName"); UA_Server_addVariableNode(server, UA_NODEID_NULL, pumpId, UA_NODEID_NUMERIC(0, UA_NS0ID_HASCOMPONENT), UA_QUALIFIEDNAME(1, "ManufacturerName"), UA_NODEID_NUMERIC(0, UA_NS0ID_BASEDATAVARIABLETYPE), mnAttr, NULL, NULL); UA_VariableAttributes modelAttr = UA_VariableAttributes_default; UA_String modelName = UA_STRING("Mega Pump 3000"); UA_Variant_setScalar(&modelAttr.value, &modelName, &UA_TYPES[UA_TYPES_STRING]); modelAttr.displayName = UA_LOCALIZEDTEXT("en-US", "ModelName"); UA_Server_addVariableNode(server, UA_NODEID_NULL, pumpId, UA_NODEID_NUMERIC(0, UA_NS0ID_HASCOMPONENT), UA_QUALIFIEDNAME(1, "ModelName"), UA_NODEID_NUMERIC(0, UA_NS0ID_BASEDATAVARIABLETYPE), modelAttr, NULL, NULL); UA_VariableAttributes statusAttr = UA_VariableAttributes_default; UA_Boolean status = true; UA_Variant_setScalar(&statusAttr.value, &status, &UA_TYPES[UA_TYPES_BOOLEAN]); statusAttr.displayName = UA_LOCALIZEDTEXT("en-US", "Status"); UA_Server_addVariableNode(server, UA_NODEID_NULL, pumpId, UA_NODEID_NUMERIC(0, UA_NS0ID_HASCOMPONENT), UA_QUALIFIEDNAME(1, "Status"), UA_NODEID_NUMERIC(0, UA_NS0ID_BASEDATAVARIABLETYPE), statusAttr, NULL, NULL); UA_VariableAttributes rpmAttr = UA_VariableAttributes_default; UA_Double rpm = 50.0; UA_Variant_setScalar(&rpmAttr.value, &rpm, &UA_TYPES[UA_TYPES_DOUBLE]); rpmAttr.displayName = UA_LOCALIZEDTEXT("en-US", "MotorRPM"); UA_Server_addVariableNode(server, UA_NODEID_NULL, pumpId, UA_NODEID_NUMERIC(0, UA_NS0ID_HASCOMPONENT), UA_QUALIFIEDNAME(1, "MotorRPMs"), UA_NODEID_NUMERIC(0, UA_NS0ID_BASEDATAVARIABLETYPE), rpmAttr, NULL, NULL); } /** * Object types, type hierarchies and instantiation * ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ * Building up each object manually requires us to write a lot of code. * Furthermore, there is no way for clients to detect that an object represents * a pump. (We might use naming conventions or similar to detect pumps. But * that's not exactly a clean solution.) Furthermore, we might have more devices * than just pumps. And we require all devices to share some common structure. * The solution is to define ObjectTypes in a hierarchy with inheritance * relations. * * .. graphviz:: * * digraph tree { * * fixedsize=true; * node [width=2, height=0, shape=box, fillcolor="#E5E5E5", concentrate=true] * * node_root [label=< ObjectTypeNode
Device >] * * { rank=same * point_1 [shape=point] * node_1 [label=< VariableNode
ManufacturerName
(mandatory) >] } * node_root -> point_1 [arrowhead=none] * point_1 -> node_1 [label="hasComponent"] * * { rank=same * point_2 [shape=point] * node_2 [label=< VariableNode
ModelName >] } * point_1 -> point_2 [arrowhead=none] * point_2 -> node_2 [label="hasComponent"] * * { rank=same * point_3 [shape=point] * node_3 [label=< ObjectTypeNode
Pump >] } * point_2 -> point_3 [arrowhead=none] * point_3 -> node_3 [label="hasSubtype"] * * { rank=same * point_4 [shape=point] * node_4 [label=< VariableNode
Status
(mandatory) >] } * node_3 -> point_4 [arrowhead=none] * point_4 -> node_4 [label="hasComponent"] * * { rank=same * point_5 [shape=point] * node_5 [label=< VariableNode
MotorRPM >] } * point_4 -> point_5 [arrowhead=none] * point_5 -> node_5 [label="hasComponent"] * * } * * Children that are marked mandatory are automatically instantiated together * with the parent object. This is indicated by a `hasModellingRule` reference * to an object that representes the `mandatory` modelling rule. */ /* predefined identifier for later use */ UA_NodeId pumpTypeId = {1, UA_NODEIDTYPE_NUMERIC, {1001}}; static void defineObjectTypes(UA_Server *server) { /* Define the object type for "Device" */ UA_NodeId deviceTypeId; /* get the nodeid assigned by the server */ UA_ObjectTypeAttributes dtAttr = UA_ObjectTypeAttributes_default; dtAttr.displayName = UA_LOCALIZEDTEXT("en-US", "DeviceType"); UA_Server_addObjectTypeNode(server, UA_NODEID_NULL, UA_NODEID_NUMERIC(0, UA_NS0ID_BASEOBJECTTYPE), UA_NODEID_NUMERIC(0, UA_NS0ID_HASSUBTYPE), UA_QUALIFIEDNAME(1, "DeviceType"), dtAttr, NULL, &deviceTypeId); UA_VariableAttributes mnAttr = UA_VariableAttributes_default; mnAttr.displayName = UA_LOCALIZEDTEXT("en-US", "ManufacturerName"); UA_NodeId manufacturerNameId; UA_Server_addVariableNode(server, UA_NODEID_NULL, deviceTypeId, UA_NODEID_NUMERIC(0, UA_NS0ID_HASCOMPONENT), UA_QUALIFIEDNAME(1, "ManufacturerName"), UA_NODEID_NUMERIC(0, UA_NS0ID_BASEDATAVARIABLETYPE), mnAttr, NULL, &manufacturerNameId); /* Make the manufacturer name mandatory */ UA_Server_addReference(server, manufacturerNameId, UA_NODEID_NUMERIC(0, UA_NS0ID_HASMODELLINGRULE), UA_EXPANDEDNODEID_NUMERIC(0, UA_NS0ID_MODELLINGRULE_MANDATORY), true); UA_VariableAttributes modelAttr = UA_VariableAttributes_default; modelAttr.displayName = UA_LOCALIZEDTEXT("en-US", "ModelName"); UA_Server_addVariableNode(server, UA_NODEID_NULL, deviceTypeId, UA_NODEID_NUMERIC(0, UA_NS0ID_HASCOMPONENT), UA_QUALIFIEDNAME(1, "ModelName"), UA_NODEID_NUMERIC(0, UA_NS0ID_BASEDATAVARIABLETYPE), modelAttr, NULL, NULL); /* Define the object type for "Pump" */ UA_ObjectTypeAttributes ptAttr = UA_ObjectTypeAttributes_default; ptAttr.displayName = UA_LOCALIZEDTEXT("en-US", "PumpType"); UA_Server_addObjectTypeNode(server, pumpTypeId, deviceTypeId, UA_NODEID_NUMERIC(0, UA_NS0ID_HASSUBTYPE), UA_QUALIFIEDNAME(1, "PumpType"), ptAttr, NULL, NULL); UA_VariableAttributes statusAttr = UA_VariableAttributes_default; statusAttr.displayName = UA_LOCALIZEDTEXT("en-US", "Status"); statusAttr.valueRank = UA_VALUERANK_SCALAR; UA_NodeId statusId; UA_Server_addVariableNode(server, UA_NODEID_NULL, pumpTypeId, UA_NODEID_NUMERIC(0, UA_NS0ID_HASCOMPONENT), UA_QUALIFIEDNAME(1, "Status"), UA_NODEID_NUMERIC(0, UA_NS0ID_BASEDATAVARIABLETYPE), statusAttr, NULL, &statusId); /* Make the status variable mandatory */ UA_Server_addReference(server, statusId, UA_NODEID_NUMERIC(0, UA_NS0ID_HASMODELLINGRULE), UA_EXPANDEDNODEID_NUMERIC(0, UA_NS0ID_MODELLINGRULE_MANDATORY), true); UA_VariableAttributes rpmAttr = UA_VariableAttributes_default; rpmAttr.displayName = UA_LOCALIZEDTEXT("en-US", "MotorRPM"); rpmAttr.valueRank = UA_VALUERANK_SCALAR; UA_Server_addVariableNode(server, UA_NODEID_NULL, pumpTypeId, UA_NODEID_NUMERIC(0, UA_NS0ID_HASCOMPONENT), UA_QUALIFIEDNAME(1, "MotorRPMs"), UA_NODEID_NUMERIC(0, UA_NS0ID_BASEDATAVARIABLETYPE), rpmAttr, NULL, NULL); } /** * Now we add the derived ObjectType for the pump that inherits from the device * object type. The resulting object contains all mandatory child variables. * These are simply copied over from the object type. The object has a reference * of type ``hasTypeDefinition`` to the object type, so that clients can detect * the type-instance relation at runtime. */ static void addPumpObjectInstance(UA_Server *server, char *name) { UA_ObjectAttributes oAttr = UA_ObjectAttributes_default; oAttr.displayName = UA_LOCALIZEDTEXT("en-US", name); UA_Server_addObjectNode(server, UA_NODEID_NULL, UA_NODEID_NUMERIC(0, UA_NS0ID_OBJECTSFOLDER), UA_NODEID_NUMERIC(0, UA_NS0ID_ORGANIZES), UA_QUALIFIEDNAME(1, name), pumpTypeId, /* this refers to the object type identifier */ oAttr, NULL, NULL); } /** * Often we want to run a constructor function on a new object. This is * especially useful when an object is instantiated at runtime (with the * AddNodes service) and the integration with an underlying process cannot be * manually defined. In the following constructor example, we simply set the * pump status to on. */ static UA_StatusCode pumpTypeConstructor(UA_Server *server, const UA_NodeId *sessionId, void *sessionContext, const UA_NodeId *typeId, void *typeContext, const UA_NodeId *nodeId, void **nodeContext) { UA_LOG_INFO(UA_Log_Stdout, UA_LOGCATEGORY_USERLAND, "New pump created"); /* Find the NodeId of the status child variable */ UA_RelativePathElement rpe; UA_RelativePathElement_init(&rpe); rpe.referenceTypeId = UA_NODEID_NUMERIC(0, UA_NS0ID_HASCOMPONENT); rpe.isInverse = false; rpe.includeSubtypes = false; rpe.targetName = UA_QUALIFIEDNAME(1, "Status"); UA_BrowsePath bp; UA_BrowsePath_init(&bp); bp.startingNode = *nodeId; bp.relativePath.elementsSize = 1; bp.relativePath.elements = &rpe; UA_BrowsePathResult bpr = UA_Server_translateBrowsePathToNodeIds(server, &bp); if(bpr.statusCode != UA_STATUSCODE_GOOD || bpr.targetsSize < 1) return bpr.statusCode; /* Set the status value */ UA_Boolean status = true; UA_Variant value; UA_Variant_setScalar(&value, &status, &UA_TYPES[UA_TYPES_BOOLEAN]); UA_Server_writeValue(server, bpr.targets[0].targetId.nodeId, value); UA_BrowsePathResult_clear(&bpr); /* At this point we could replace the node context .. */ return UA_STATUSCODE_GOOD; } static void addPumpTypeConstructor(UA_Server *server) { UA_NodeTypeLifecycle lifecycle; lifecycle.constructor = pumpTypeConstructor; lifecycle.destructor = NULL; UA_Server_setNodeTypeLifecycle(server, pumpTypeId, lifecycle); } /** It follows the main server code, making use of the above definitions. */ static volatile UA_Boolean running = true; static void stopHandler(int sign) { UA_LOG_INFO(UA_Log_Stdout, UA_LOGCATEGORY_SERVER, "received ctrl-c"); running = false; } int main(void) { signal(SIGINT, stopHandler); signal(SIGTERM, stopHandler); UA_Server *server = UA_Server_new(); UA_ServerConfig_setDefault(UA_Server_getConfig(server)); manuallyDefinePump(server); defineObjectTypes(server); addPumpObjectInstance(server, "pump2"); addPumpObjectInstance(server, "pump3"); addPumpTypeConstructor(server); addPumpObjectInstance(server, "pump4"); addPumpObjectInstance(server, "pump5"); UA_StatusCode retval = UA_Server_run(server, &running); UA_Server_delete(server); return retval == UA_STATUSCODE_GOOD ? EXIT_SUCCESS : EXIT_FAILURE; }