custom_provider_read.c

/******************************************************************************
**
** Copyright (C) 2011-2014 Unified Automation GmbH. All Rights Reserved.
** Web: http://www.unifiedautomation.com
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
**
** Project: OPC Ansi C OPC Server Examples
**
******************************************************************************/

#include <uaserver_config.h>

#include <opcua_statuscodes.h>

#include <uaserver_read.h>
#include <uaserver_basenode.h>
#include <uaserver_utilities.h>
#include <uaserver_p_atomic.h>

#include "custom_provider_helper.h"

OPCUA_BEGIN_EXTERN_C

IFMETHODIMP(CustomProvider_ReadAsync)(UaServer_ProviderReadContext *a_pReadCtx)
{
    OpcUa_ReadRequest       *pReq;
    OpcUa_ReadResponse      *pRes;
    OpcUa_Int32              i;
    OpcUa_BaseNode          *pNode;
    OpcUa_NodeId            *pNodeId       = OpcUa_Null;
    UaServer_AddressSpace   *pAddressSpace = &(g_pCustomProvider->AddressSpace);

OpcUa_InitializeStatus(OpcUa_Module_Server, "CustomProvider_ReadAsync");

    OpcUa_ReturnErrorIfArgumentNull(a_pReadCtx);

    pReq = a_pReadCtx->pRequest;
    pRes = a_pReadCtx->pResponse;

    /* We will send exactly one callback */
    UaServer_Atomic_Increment(&a_pReadCtx->nOutstandingCbs);

    /* Iterate over nodes and check if the provider is responsible for processing them */
    for (i = 0; i < pReq->NoOfNodesToRead; i++)
    {
        if (pReq->NodesToRead[i].NodeId.NamespaceIndex == g_uCustomProvider_NamespaceIndex)
        {
            pNodeId = &(pReq->NodesToRead[i].NodeId);
            UaServer_GetNode(pAddressSpace, pNodeId, &pNode);
            if (pNode)
            {
                UserDataCommon *pUserData = OpcUa_Null;
                if ( (a_pReadCtx->pRequest->NodesToRead[i].AttributeId == OpcUa_Attributes_Value &&
                      OpcUa_BaseNode_GetType(pNode) == eVariable &&
                      (OpcUa_Variable_GetAccessLevel(pNode) & OpcUa_AccessLevels_CurrentRead) == 0) )
                {
                    pRes->Results[i].StatusCode = OpcUa_BadNotReadable;
                    continue;
                }

                pUserData = (UserDataCommon*)OpcUa_BaseNode_GetUserData(pNode);
                if (pUserData != OpcUa_Null &&
                    a_pReadCtx->pRequest->NodesToRead[i].AttributeId == OpcUa_Attributes_Value)
                {
                    switch (pUserData->Type)
                    {
                    case UserDataTemperature:
                        {
                            TemperatureSensor *pSensor = (TemperatureSensor*)pUserData;
                            pRes->Results[i].Value.Datatype = OpcUaType_Double;
                            pRes->Results[i].Value.Value.Double = *pSensor->pValue;
                            pRes->Results[i].StatusCode = OpcUa_Good;
                            break;
                        }
                    case UserDataMachineSwitch:
                        {
                            MachineSwitch *pSwitch = (MachineSwitch*)pUserData;
                            pRes->Results[i].Value.Datatype = OpcUaType_Boolean;
                            pRes->Results[i].Value.Value.Boolean = *pSwitch->pValue;
                            pRes->Results[i].StatusCode = OpcUa_Good;
                            break;
                        }
                    default:
                        {
                            pRes->Results[i].StatusCode = OpcUa_BadNotReadable;
                            break;
                        }
                    }

                    /* Set timestamps */
                    if (OpcUa_IsGood(pRes->Results[i].StatusCode))
                    {
                        if (a_pReadCtx->pRequest->TimestampsToReturn == OpcUa_TimestampsToReturn_Source ||
                            a_pReadCtx->pRequest->TimestampsToReturn == OpcUa_TimestampsToReturn_Both)
                        {
                            pRes->Results[i].SourceTimestamp = OpcUa_DateTime_UtcNow();
                        }
                        if (a_pReadCtx->pRequest->TimestampsToReturn == OpcUa_TimestampsToReturn_Server ||
                            a_pReadCtx->pRequest->TimestampsToReturn == OpcUa_TimestampsToReturn_Both)
                        {
                            pRes->Results[i].ServerTimestamp = OpcUa_DateTime_UtcNow();
                        }
                    }
                }
                else
                {
                    /* Use the SDK's helper function to process the request */
                    UaServer_ReadInternal(pNode, a_pReadCtx, i);
                }
            }
            else
            {
                pRes->Results[i].StatusCode = OpcUa_BadNodeIdUnknown;
            }
        }
    }

    /* Send callback */
    UaServer_ReadComplete(a_pReadCtx);

OpcUa_ReturnStatusCode;
OpcUa_BeginErrorHandling;
OpcUa_FinishErrorHandling;
}

OPCUA_END_EXTERN_C