Question

I’m using NServiceBus 3 and when I receive a message I’m getting this error from the receiving endpoint.:

NServiceBus.Unicast.Transport.Transactional.TransactionalTransport [(null)] <(null)> - Failed raising 'transport message received' event for message with ID=97d0f2fa-6227-439b-ad37-a304bd2af000\10428
System.NullReferenceException: Object reference not set to an instance of an object.
   at NServiceBus.MessageHeaders.MessageHeaderManager.GetHeader(Object message, String key)
   at NServiceBus.MessageHeaders.Bootstrapper.<Run>b__0(Object msg, String key)
   at NServiceBus.ExtensionMethods.GetHeader(Object msg, String key)
   at NServiceBus.ExtensionMethods.GetOriginatingSiteHeader(Object msg)
   at NServiceBus.Gateway.HeaderManagement.GatewayHeaderManager.MutateIncoming(Object message)
   at NServiceBus.Unicast.UnicastBus.<>c__DisplayClass25.<ApplyIncomingMessageMutatorsTo>b__24(IMutateIncomingMessages m)
   at System.Collections.Generic.List`1.ForEach(Action`1 action)
   at NServiceBus.Unicast.UnicastBus.ApplyIncomingMessageMutatorsTo(IBuilder builder, Object originalMessage)
   at NServiceBus.Unicast.UnicastBus.<>c__DisplayClass22.<HandleMessage>b__21(Object msg)
   at System.Linq.Enumerable.WhereSelectArrayIterator`2.MoveNext()
   at System.Linq.Buffer`1..ctor(IEnumerable`1 source)
   at System.Linq.Enumerable.ToArray[TSource](IEnumerable`1 source)
   at NServiceBus.Unicast.UnicastBus.HandleMessage(IBuilder builder, TransportMessage m)
   at NServiceBus.Unicast.UnicastBus.HandleTransportMessage(IBuilder childBuilder, TransportMessage msg)
   at NServiceBus.Unicast.UnicastBus.TransportMessageReceived(Object sender, TransportMessageReceivedEventArgs e)
   at System.EventHandler`1.Invoke(Object sender, TEventArgs e)
   at NServiceBus.Unicast.Transport.Transactional.TransactionalTransport.OnTransportMessageReceived(TransportMessage msg)

The message itself looks like this:

public interface ILinkPersonMessage : IBaseMessage
{
    int PersonId { get; set; }
    List<int> UnitIds { get; set; }
}

public interface IBaseMessage
{
    int UserId { get; set; }
}

In the sending class I’m doing this:

var message = bus.CreateInstance<ILinkPersonMessage>();
message.UserId = currentUser.UserId;
message.PersonId = personId;
message.UnitIds = selectedUnits;

bus.Send(message);

Update:

I’m looking through the NServiceBus code, and this is the method that’s throwing the error:

    public string GetHeader(object message, string key)
    {
        if (message == ExtensionMethods.CurrentMessageBeingHandled)
            if (bus.CurrentMessageContext.Headers.ContainsKey(key))
                return bus.CurrentMessageContext.Headers[key];
            else
                return null;

        if (messageHeaders == null)
            return null;

        if (!messageHeaders.ContainsKey(message))
            return null;

        if (messageHeaders[message].ContainsKey(key))
            return messageHeaders[message][key];

        return null;
    }

From looking at that code, this could only be happening if bus.CurrentMessageContext or bus.CurrentMessageContext.Headers are null, or if messageHeaders[message] existed, but contained a null value. Unfortunately I haven’t been able to figure out yet which one of these scenarios is more likely (or even possible)

Update 2

So using QueueExplorer I’ve pulled the headers out:

<?xml version="1.0"?>
<ArrayOfHeaderInfo xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <HeaderInfo>
        <Key>NServiceBus.Version</Key>
        <Value>3.0.3</Value>
    </HeaderInfo>
    <HeaderInfo>
        <Key>NServiceBus.TimeSent</Key>
        <Value>2012-05-08 06:57:15:691208 Z</Value>
    </HeaderInfo>
    <HeaderInfo>
        <Key>NServiceBus.EnclosedMessageTypes</Key>
        <Value>Namespace.Service.ILinkPersonMessage __impl, NServiceBus.Unicast.Transport__impl, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null;Namespace.Service.ILinkPersonMessage, Namespace.Service, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null</Value>
    </HeaderInfo>
    <HeaderInfo>
        <Key>WinIdName</Key>
        <Value>*{myusername}*</Value>
    </HeaderInfo>
    <HeaderInfo>
        <Key>CorrId</Key>
    </HeaderInfo>
</ArrayOfHeaderInfo>

Update 3

This is the fluent config that now works:

Configure.With()
.DefiningEventsAs(t => t.Namespace != null && t.Namespace.StartsWith("Events"))
.DefiningCommandsAs(t => t.Namespace != null && t.Namespace.StartsWith("Messages"))
.CastleWindsorBuilder(container)
.XmlSerializer()
.MsmqTransport()
.IsTransactional(true)
.IsolationLevel(IsolationLevel.ReadUncommitted)
.UnicastBus()
.RavenSagaPersister()
.RavenSubscriptionStorage()
.UseRavenTimeoutPersister()
.RunTimeoutManager()
.ForInstallationOn<NServiceBus.Installation.Environments.Windows>().Install();

(I’ve trimmed all the namespaces)

Answer 1

Does this happen on the first message after sending process startup, or just subsequent ones?

Are you configuring your sending bus more than once? (NServiceBus.Configure?)