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Patterns in Windows Azure Service Bus - Content-Based Router Pattern

In one of my latest post I talked about Resequencer Pattern, which can be used with success using Windows Azure Service Bus.  We saw how we can retrieve messages in the same order as they were sending to the Service Bus.
But what about Content-Based Router Pattern? The main scope of this pattern is the ability to route each message to different clients based on the data of each message. The system the process each message has to be able to redirect a message to a different consumer (client) based on the data that message contains.
One of the key features of this pattern is ability to change and maintained the rules that are used to redirect each message based on the content.
Windows Azure gives us the possibility to implement this pattern using Service Bus Topic. Each channel, where messages are redirected can be represented by a subscriber. As you already know each subscriber can have attached a filter that can filter messages based on the content. For this purpose we can use SqlFilter. Using SqlFilter we can look over the properties of a message and route them based on this purpose.
To be able to route messages based on the properties, we need to add the properties to our message. This step needs to be done on the producer side, on the system that produces messages, before adding them to the Service Bus Topic.
In the following example we will see how we can add these properties to our messages and how we can define these rules on the subscription side.
First step is to create the topic:
NamespaceManager namespaceManager = NamespaceManager.CreateFromConnectionString(

if (!namespaceManager.TopicExists("myFooTopic"))
After that, from the client side, we can create a message and send it to the topic. In our case we add a custom property named “property1”.
TopicClient topicClient = TopicClient.CreateFromConnectionString(

BrokeredMessage message = new BrokeredMessage();
message.Properties["property1"] = 10;
>Next, we need to create the subscription that accepts only messages that have property equal to 10.
topicClient.AddSubscription("Property1Equal10", new SqlFilter( "property1 == 10") );
The last step is on the consumer side. We will consume message that are sent our subscription.
SubscriptionClient subscriptionClient = SubscriptionClient.CreateFromConnectionString(

   BrokeredMessage brokeredMessage = subscriptionClient.Receive();

   if (message != null)
       catch (Exception)
There are a lot of cases when we can use this pattern. We can imagine a system that need to route messages based on the information contained in the message. For example we can have a system that process newsletters. Based on the content of the newsletters we want to redirect messages to the specific group of email. This can be very easily done using this pattern.
Last edit: A list of all patterns that can be used with Windows Azure Service Bus, that were described by me LINK.  


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