Azure service bus implementation - azure

Question

Basically my ‘Maintopic’ topic receives three types of xml files (‘TEST’,’DEV’,’PROD’).
‘MainSubscription’ subscribes to that topic and now based on the XML file type, I need to route the XML files to:
Respective topics (child topics).
See the below message flow.
Maintopic --à MainSubscription’ (Filter on xml node type)-- > child topic 1 ( xml node type=’TEST’)
child topic 2 ( xml node type=’DEV’)
child topic 3 ( xml node type=’PROD)
I can add a subscription to the ‘Maintopic’, but where can I define all the filter logic for routing the file?
I am new to Azure cloud, how can I do this? I don't even know where to start.

Answer 1

Service Bus supports three filter conditions:
Boolean filters - The TrueFilter and FalseFilter either cause all arriving messages (true) or none of the arriving messages (false) to be selected for the subscription.
SQL Filters - A SqlFilter holds a SQL-like conditional expression that is evaluated in the broker against the arriving messages' user-defined properties and system properties.
Correlation Filters - A CorrelationFilter holds a set of conditions that are matched against one or more of an arriving message's user and system properties.
You must create a filtered subscription which will only receive messages you are interested in.
A filter can be based on any properties of the BrokeredMessage, except the body, since that would require every message to be desterilized in order to be handed on to the correct subscriptions. You can use sql filter.
An example of sql filter is below –
if (!namespaceManager.SubscriptionExists(topicName, filteredSubName1))
{
namespaceManager.CreateSubscription(topicName, filteredSubName1, new SqlFilter("From LIKE '%Smith'"));
}
You don’t send your messages directly to a subscription, you send them to the topic, and that will forward them to all the relevant subscriptions based on their filters. Below is the example -
var message1 = new BrokeredMessage("Second message");
message1.Properties["From"] = "Alan Smith";
var client = TopicClient.CreateFromConnectionString(connectionString, topicName);
client.Send(message1);
Below is how you receive message –
var subClient = SubscriptionClient.CreateFromConnectionString(connectionString, topicName, subscriptionName);
var received = subClient.ReceiveBatch(10, TimeSpan.FromSeconds(5));
foreach (var message in received)
{
Console.WriteLine("{0} '{1}' Label: '{2}' From: '{3}'",
subscriptionName,
message.GetBody<string>(),
message.Label,
message.Properties["From"]);
}