Opc.Ua.Server.CustomNodeManager.HistoryRead C# (CSharp) Method

        protected virtual ServiceResult HistoryRead(
            ISystemContext context, 
            NodeState           source,
            HistoryReadDetails  details, 
            TimestampsToReturn  timestampsToReturn, 
            bool                releaseContinuationPoints, 
            HistoryReadValueId  nodesToRead, 
            HistoryReadResult   result)
        {
            // check for variable.
            BaseVariableState variable = source as BaseVariableState;

            if (variable == null)
            {
                return StatusCodes.BadHistoryOperationUnsupported;
            }

            // check for access.
            lock (Lock)
            {
                if ((variable.AccessLevel & AccessLevels.HistoryRead) == 0)
                {
                    return StatusCodes.BadNotReadable;
                }
            }

            // handle read raw.
            ReadRawModifiedDetails readRawDetails = details as ReadRawModifiedDetails;

            if (readRawDetails != null)
            {
                return HistoryReadRaw(
                    context,
                    variable,
                    readRawDetails,
                    timestampsToReturn,
                    releaseContinuationPoints,
                    nodesToRead,
                    result);
            }

            // handle read processed.
            ReadProcessedDetails readProcessedDetails = details as ReadProcessedDetails;

            if (readProcessedDetails != null)
            {
                return HistoryReadProcessed(
                    context,
                    variable,
                    readProcessedDetails,
                    timestampsToReturn,
                    releaseContinuationPoints,
                    nodesToRead,
                    result);
            }

            // handle read processed.
            ReadAtTimeDetails readAtTimeDetails = details as ReadAtTimeDetails;

            if (readAtTimeDetails != null)
            {
                return HistoryReadAtTime(
                    context,
                    variable,
                    readAtTimeDetails,
                    timestampsToReturn,
                    releaseContinuationPoints,
                    nodesToRead,
                    result);
            }
 
            return StatusCodes.BadHistoryOperationUnsupported;
        }