使用筛选订阅从主题中检索 Azure 服务总线消息

Question

我正在尝试关注 Mark Heath 的控制台应用程序 example 以使用过滤订阅检索服务总线主题消息。但是，我实际上无法检索实际过滤的消息（Filtered1、Filtered2）。消息确实被消耗了，但我无法查看它们，因为代码永远不会像处理非过滤消息 (AllMessages) 那样进入回调函数。关于我所缺少的任何想法？

发件人代码

var body = "Hello World";
var message1 = new BrokeredMessage(body);
message1.Properties["From"] = "Ian Wright";

var message2 = new BrokeredMessage("Second message");
message2.Properties["From"] = "Alan Smith";
message2.Label = "important";

var message3 = new BrokeredMessage("Third message");
message3.Properties["From"] = "Kelly Smith";
message3.Label = "information";

var client =  TopicClient.CreateFromConnectionString(servicebusConnectionString, topicName);
 client.Send(message1);
 client.Send(message2);
 client.Send(message3);

接收者代码

const string topicName = "rightangle";
const string subscriptionName = "AllMessages";
const string sub1Name = "Filtered1";
const string sub2Name = "Filtered2";

NamespaceManager namespaceManager = NamespaceManager.CreateFromConnectionString(connectionString);

if (!namespaceManager.SubscriptionExists(topicName, subscriptionName))
{
    namespaceManager.CreateSubscription(topicName, subscriptionName);
}
if (namespaceManager.SubscriptionExists(topicName, sub1Name))
{
    Console.WriteLine("Deleting subscription {0}", sub1Name);
    namespaceManager.DeleteSubscription(topicName, sub1Name);
}
Console.WriteLine("Creating subscription {0}", sub1Name);
namespaceManager.CreateSubscription(topicName, sub1Name, new SqlFilter("From LIKE '%Smith'"));

if (namespaceManager.SubscriptionExists(topicName, sub2Name))
{
    Console.WriteLine("Deleting subscription {0}", sub2Name);
    namespaceManager.DeleteSubscription(topicName, sub2Name);
}
Console.WriteLine("Creating subscription {0}", sub2Name);
namespaceManager.CreateSubscription(topicName, sub2Name, new SqlFilter("sys.Label='important'"));

var options = new OnMessageOptions();

var subClient =                    SubscriptionClient.CreateFromConnectionString(connectionString, topicName, subscriptionName);
subClient.OnMessage(m => MessageReceived(subscriptionName, m), options);

var subClient1 =                    SubscriptionClient.CreateFromConnectionString(connectionString, topicName, sub1Name);

subClient1.OnMessage(m => MessageReceived(sub1Name, m), options);

var subClient2 =                    SubscriptionClient.CreateFromConnectionString(connectionString, topicName, sub2Name);

subClient2.OnMessage(m => MessageReceived(sub2Name, m), options);

private static void MessageReceived(string subscriptionName, BrokeredMessage message)
{
   Console.WriteLine("{0} '{1}' Label: '{2}' From: '{3}'", subscriptionName,
            message.GetBody<string>(),
            message.Label,
            message.Properties["From"]);

}

Answer 1

代码很好。运行此示例后，AllMessages 包含三条消息，Filtered1 有两条消息，Filtered2 有一条消息。您确定没有其他使用代码的实例正在运行并检索这些消息吗？

AllMessages 有一个默认的 SQL 过滤器，所以它是一个“包罗万象”的订阅。过滤不会影响它，它应该将 any 消息发送到rightangle 主题。如果您在其下看不到任何消息，则表明消息已被消耗，或者应用程序正在重新构建实体并因此删除所有消息。

尝试更改接收方代码以不删除实体，而仅接收。并修改发件人以确保实体存在，如果不创建实体，但不删除。或者，您可以将两者结合起来（首先是接收者代码，然后是发送者），您将看到这些消息。问题仅在于如何管理（删除）实体。