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Set subscriptions filters in Azure Service Bus | Microsoft Docs
This article provides examples for defining filters and actions on Azure Service Bus topic subscriptions.
how-to
02/23/2024
csharp
devx-track-dotnet

Set subscription filters (Azure Service Bus)

This article provides a few examples on setting filters on subscriptions for Service Bus topics. For conceptual information about filters, see Filters.

Filter on system properties

To refer to a system property in a filter, use the following format: sys.<system-property-name>.

sys.label LIKE '%bus%'
sys.messageid = 'xxxx'
sys.correlationid like 'abc-%'

Note

Filter on message properties

Here are the examples of using application or user properties in a filter. You can access application properties set by using Azure.Messaging.ServiceBus.ServiceBusMessage.ApplicationProperties) (latest) or user properties set by Microsoft.Azure.ServiceBus.ServiceBusMessage (deprecated) using the syntax: user.property-name or just property-name.

MessageProperty = 'A'
user.SuperHero like 'SuperMan%'

[!INCLUDE service-bus-track-0-and-1-sdk-support-retirement]

Filter on message properties with special characters

If the message property name has special characters, use double quotes (") to enclose the property name. For example if the property name is "http://schemas.microsoft.com/xrm/2011/Claims/EntityLogicalName", use the following syntax in the filter.

"http://schemas.microsoft.com/xrm/2011/Claims/EntityLogicalName" = 'account'

Filter on message properties with numeric values

The following examples show how you can use properties with numeric values in filters.

MessageProperty = 1
MessageProperty > 1
MessageProperty > 2.08
MessageProperty = 1 AND MessageProperty2 = 3
MessageProperty = 1 OR MessageProperty2 = 3

Parameter-based filters

Here are a few examples of using parameter-based filters. In these examples, DataTimeMp is a message property of type DateTime and @dtParam is a parameter passed to the filter as a DateTime object.

DateTimeMp < @dtParam
DateTimeMp > @dtParam

(DateTimeMp2-DateTimeMp1) <= @timespan //@timespan is a parameter of type TimeSpan
DateTimeMp2-DateTimeMp1 <= @timespan

Using IN and NOT IN

StoreId IN('Store1', 'Store2', 'Store3')

sys.To IN ('Store5','Store6','Store7') OR StoreId = 'Store8'

sys.To NOT IN ('Store1','Store2','Store3','Store4','Store5','Store6','Store7','Store8') OR StoreId NOT IN ('Store1','Store2','Store3','Store4','Store5','Store6','Store7','Store8')

For a C# sample, see Topic Filters sample on GitHub.

Correlation filters

Correlation filter using CorrelationID

new CorrelationFilter("Contoso");

It filters messages with CorrelationID set to Contoso.

Note

The CorrelationRuleFilter class in .NET is in the Azure.Messaging.ServiceBus.Administration namespace. For sample code that shows how to create filters in general using .NET, see this code on GitHub.

Correlation filter using system and user properties

var filter = new CorrelationRuleFilter();
filter.Label = "Important";
filter.ReplyTo = "johndoe@contoso.com";
filter.Properties["color"] = "Red";

It's equivalent to: sys.ReplyTo = 'johndoe@contoso.com' AND sys.Label = 'Important' AND color = 'Red'

.NET example for creating subscription filters

Here's a .NET C# example that creates the following Service Bus entities:

  • Service Bus topic named topicfiltersampletopic
  • Subscription to the topic named AllOrders with a True Rule filter, which is equivalent to a SQL rule filter with expression 1=1.
  • Subscription named ColorBlueSize10Orders with a SQL filter expression color='blue' AND quantity=10
  • Subscription named ColorRed with a SQL filter expression color='red' and an action
  • Subscription named HighPriorityRedOrders with a correlation filter expression Subject = "red", CorrelationId = "high"

See the inline code comments for more details.

namespace CreateTopicsAndSubscriptionsWithFilters
{
    using Azure.Messaging.ServiceBus.Administration;
    using System;
    using System.Threading.Tasks;

    public class Program
    {
        // Service Bus Administration Client object to create topics and subscriptions
        static ServiceBusAdministrationClient adminClient;

        // connection string to the Service Bus namespace
        static readonly string connectionString = "<YOUR SERVICE BUS NAMESPACE - CONNECTION STRING>";

        // name of the Service Bus topic
        static readonly string topicName = "topicfiltersampletopic";

        // names of subscriptions to the topic
        static readonly string subscriptionAllOrders = "AllOrders";
        static readonly string subscriptionColorBlueSize10Orders = "ColorBlueSize10Orders";
        static readonly string subscriptionColorRed = "ColorRed";
        static readonly string subscriptionHighPriorityRedOrders = "HighPriorityRedOrders";

        public static async Task Main()
        {
            try
            {

                Console.WriteLine("Creating the Service Bus Administration Client object");
                adminClient = new ServiceBusAdministrationClient(connectionString);
                
                Console.WriteLine($"Creating the topic {topicName}");
                await adminClient.CreateTopicAsync(topicName);

                Console.WriteLine($"Creating the subscription {subscriptionAllOrders} for the topic with a True filter ");
                // Create a True Rule filter with an expression that always evaluates to true
                // It's equivalent to using SQL rule filter with 1=1 as the expression
                await adminClient.CreateSubscriptionAsync(
                        new CreateSubscriptionOptions(topicName, subscriptionAllOrders), 
                        new CreateRuleOptions("AllOrders", new TrueRuleFilter()));


                Console.WriteLine($"Creating the subscription {subscriptionColorBlueSize10Orders} with a SQL filter");
                // Create a SQL filter with color set to blue and quantity to 10
                await adminClient.CreateSubscriptionAsync(
                        new CreateSubscriptionOptions(topicName, subscriptionColorBlueSize10Orders), 
                        new CreateRuleOptions("BlueSize10Orders", new SqlRuleFilter("color='blue' AND quantity=10")));

                Console.WriteLine($"Creating the subscription {subscriptionColorRed} with a SQL filter");
                // Create a SQL filter with color equals to red and a SQL action with a set of statements
                await adminClient.CreateSubscriptionAsync(topicName, subscriptionColorRed);
                // remove the $Default rule
                await adminClient.DeleteRuleAsync(topicName, subscriptionColorRed, "$Default");
                // now create the new rule. notice that user. prefix is used for the user/application property
                await adminClient.CreateRuleAsync(topicName, subscriptionColorRed, new CreateRuleOptions 
                                { 
                                    Name = "RedOrdersWithAction",
                                    Filter = new SqlRuleFilter("user.color='red'"),
                                    Action = new SqlRuleAction("SET quantity = quantity / 2; REMOVE priority;SET sys.CorrelationId = 'low';")

                                }
                );

                Console.WriteLine($"Creating the subscription {subscriptionHighPriorityRedOrders} with a correlation filter");
                // Create a correlation filter with color set to Red and priority set to High
                await adminClient.CreateSubscriptionAsync(
                        new CreateSubscriptionOptions(topicName, subscriptionHighPriorityRedOrders), 
                        new CreateRuleOptions("HighPriorityRedOrders", new CorrelationRuleFilter() {Subject = "red", CorrelationId = "high"} ));

                // delete resources
                //await adminClient.DeleteTopicAsync(topicName);
            }
            catch (Exception e)
            {
                Console.WriteLine(e.ToString());
            }
        }
    }
}

.NET example for sending receiving messages

namespace SendAndReceiveMessages
{
    using System;
    using System.Text;
    using System.Threading.Tasks;
    using Azure.Messaging.ServiceBus;
    using Newtonsoft.Json;
    
    public class Program 
    {
        const string TopicName = "TopicFilterSampleTopic";
        const string SubscriptionAllMessages = "AllOrders";
        const string SubscriptionColorBlueSize10Orders = "ColorBlueSize10Orders";
        const string SubscriptionColorRed = "ColorRed";
        const string SubscriptionHighPriorityOrders = "HighPriorityRedOrders";

        // connection string to your Service Bus namespace
        static string connectionString = "<YOUR SERVICE BUS NAMESPACE - CONNECTION STRING>";

        // the client that owns the connection and can be used to create senders and receivers
        static ServiceBusClient client;

        // the sender used to publish messages to the topic
        static ServiceBusSender sender;

        // the receiver used to receive messages from the subscription 
        static ServiceBusReceiver receiver;

        public async Task SendAndReceiveTestsAsync(string connectionString)
        {
            // This sample demonstrates how to use advanced filters with ServiceBus topics and subscriptions.
            // The sample creates a topic and 3 subscriptions with different filter definitions.
            // Each receiver will receive matching messages depending on the filter associated with a subscription.

            // Send sample messages.
            await this.SendMessagesToTopicAsync(connectionString);

            // Receive messages from subscriptions.
            await this.ReceiveAllMessageFromSubscription(connectionString, SubscriptionAllMessages);
            await this.ReceiveAllMessageFromSubscription(connectionString, SubscriptionColorBlueSize10Orders);
            await this.ReceiveAllMessageFromSubscription(connectionString, SubscriptionColorRed);
            await this.ReceiveAllMessageFromSubscription(connectionString, SubscriptionHighPriorityOrders);
        }


        async Task SendMessagesToTopicAsync(string connectionString)
        {
            // Create the clients that we'll use for sending and processing messages.
            client = new ServiceBusClient(connectionString);
            sender = client.CreateSender(TopicName);

            Console.WriteLine("\nSending orders to topic.");

            // Now we can start sending orders.
            await Task.WhenAll(
                SendOrder(sender, new Order()),
                SendOrder(sender, new Order { Color = "blue", Quantity = 5, Priority = "low" }),
                SendOrder(sender, new Order { Color = "red", Quantity = 10, Priority = "high" }),
                SendOrder(sender, new Order { Color = "yellow", Quantity = 5, Priority = "low" }),
                SendOrder(sender, new Order { Color = "blue", Quantity = 10, Priority = "low" }),
                SendOrder(sender, new Order { Color = "blue", Quantity = 5, Priority = "high" }),
                SendOrder(sender, new Order { Color = "blue", Quantity = 10, Priority = "low" }),
                SendOrder(sender, new Order { Color = "red", Quantity = 5, Priority = "low" }),
                SendOrder(sender, new Order { Color = "red", Quantity = 10, Priority = "low" }),
                SendOrder(sender, new Order { Color = "red", Quantity = 5, Priority = "low" }),
                SendOrder(sender, new Order { Color = "yellow", Quantity = 10, Priority = "high" }),
                SendOrder(sender, new Order { Color = "yellow", Quantity = 5, Priority = "low" }),
                SendOrder(sender, new Order { Color = "yellow", Quantity = 10, Priority = "low" })
                );

            Console.WriteLine("All messages sent.");
        }

        async Task SendOrder(ServiceBusSender sender, Order order)
        {
            var message = new ServiceBusMessage(Encoding.UTF8.GetBytes(JsonConvert.SerializeObject(order)))
            {
                CorrelationId = order.Priority,
                Subject = order.Color,
                ApplicationProperties =
                {
                    { "color", order.Color },
                    { "quantity", order.Quantity },
                    { "priority", order.Priority }
                }
            };
            await sender.SendMessageAsync(message);

            Console.WriteLine("Sent order with Color={0}, Quantity={1}, Priority={2}", order.Color, order.Quantity, order.Priority);
        }

        async Task ReceiveAllMessageFromSubscription(string connectionString, string subsName)
        {
            var receivedMessages = 0;

            receiver = client.CreateReceiver(TopicName, subsName, new ServiceBusReceiverOptions() { ReceiveMode = ServiceBusReceiveMode.ReceiveAndDelete } );
            
            // Create a receiver from the subscription client and receive all messages.
            Console.WriteLine("\nReceiving messages from subscription {0}.", subsName);

            while (true)
            {
                var receivedMessage = await receiver.ReceiveMessageAsync(TimeSpan.FromSeconds(10));
                if (receivedMessage != null)
                {
                    foreach (var prop in receivedMessage.ApplicationProperties)
                    {
                        Console.Write("{0}={1},", prop.Key, prop.Value);
                    }
                    Console.WriteLine("CorrelationId={0}", receivedMessage.CorrelationId);
                    receivedMessages++;
                }
                else
                {
                    // No more messages to receive.
                    break;
                }
            }
            Console.WriteLine("Received {0} messages from subscription {1}.", receivedMessages, subsName);
        }

       public static async Task Main()
        {
            try
            {
                Program app = new Program();
                await app.SendAndReceiveTestsAsync(connectionString);
            }
            catch (Exception e)
            {
                Console.WriteLine(e.ToString());
            }
        }
    }

    class Order
    {
        public string Color
        {
            get;
            set;
        }

        public int Quantity
        {
            get;
            set;
        }

        public string Priority
        {
            get;
            set;
        }
    }
}

Next steps

See the following samples:

Try the samples in the language of your choice to explore Azure Service Bus features.