protected override OpcAttributeValue <TAttribute> WriteAttributeValueCore <TAttribute>(
OpcWriteAttributeValueContext context,
OpcAttributeValue <TAttribute> value)
{
if (!this.manager.CanWrite(this, context.Identity))
{
throw new OpcException(OpcStatusCode.BadNotWritable);
}
return(base.WriteAttributeValueCore(context, value));
}
protected override OpcAttributeValue <TAttribute> ReadAttributeValueCore <TAttribute>(
OpcReadAttributeValueContext context,
OpcAttributeValue <TAttribute> value)
{
var attribute = value.Attribute;
// By default a user can not longer write to any node/attribute as soon the
// OpcRequestType.Write is already denied (see Program.cs).
//
// To additionally inform the client/user that its access is restricted we shall
// provide the according user dependent metadata for the UserAccessLevel and
// UserWriteAccess attributes as well.
if (attribute == OpcAttribute.UserAccessLevel || attribute == OpcAttribute.UserWriteAccess)
{
if (!this.manager.CanWrite(this, context.Identity))
{
if (value is OpcAttributeValue <OpcAccessLevel> accessLevel)
{
accessLevel = new OpcAttributeValue <OpcAccessLevel>(
value.Attribute, accessLevel.Value & ~OpcAccessLevel.CurrentWrite);
return((OpcAttributeValue <TAttribute>)(object) accessLevel);
}
if (value is OpcAttributeValue <OpcAttributeWriteAccess> writeAccess)
{
writeAccess = new OpcAttributeValue <OpcAttributeWriteAccess>(
value.Attribute, OpcAttributeWriteAccess.None);
return((OpcAttributeValue <TAttribute>)(object) writeAccess);
}
}
}
return(base.ReadAttributeValueCore(context, value));
}
