Set up a subscription for messages with no matching filter in Azure Service Bus (on-premise)

Question

I'm using Azure Service Bus 1.1 (the on premise version)

I'm trying to set up a subscription that will receive messages that have not been filtered into any other existing subscription.

I have 3 console apps, one that creates topics and subscriptions, one that sends messages to the topic, and one that receives messages from a subscription.

I'm also using the Service Bus Explorer (V2.1) to see what is happening with my console apps.

I have tried setting up the topic as described on this page and this page which uses a MatchNoneFilterExpression but the example code does not compile(?) ie the FilterAction and FilterExpression properties are not in the RuleDescription class

         RuleDescription matchNoneRule = new RuleDescription()
         {
             FilterAction = new SqlFilterAction("set defer = 'yes';"),
             FilterExpression = new MatchNoneFilterExpression()
         };

The RuleDescription class I'm using is in v2.1.0.0 of the Microsoft.ServiceBus.dll It has the following properties available,

How do I send a message that matches no other filters to a particular subscription?

Answer 1

From this page which suggests setting the EnableFilteringMessagesBeforePublishing property on the topic.

It then suggests that on sending a message to this topic a message will trigger the NoMatchingSubscriptionException

I'm creating my topic with this code

var myTopic = new TopicDescription(topicName)
{
    EnableFilteringMessagesBeforePublishing = true
};
namespaceManager.CreateTopic(myTopic);

I'm sending a message to the topic that doesn't match any filters and I can catch the exception and potentially resend the message with a property that does match a filter, e.g.:

try
{
    topicClient.Send(message);

    Console.WriteLine(string.Format("Message sent: Id = {0}, Body = {1}", message.MessageId, message.GetBody<string>()));
}
catch (NoMatchingSubscriptionException ex)
{
    string messageBody = message.GetBody<string>();                        
    BrokeredMessage msg = new BrokeredMessage(messageBody);
    msg.Properties.Add("Filter", "NoMatch");
    foreach (var prop in message.Properties)
    {
        msg.Properties.Add(prop.Key, prop.Value);
    }
    topicClient.Send(msg);

    Console.WriteLine("\n NoMatchingSubscriptionException - message resent to NoMatchingSubscription");
    Console.WriteLine(string.Format("Message sent: Id = {0}, Body = {1}", msg.MessageId, msg.GetBody<string>()));
}