Azure Service Bus “ReceiveAsync”

问题:

Is there a way, using the Microsoft.Azure.ServiceBus package, to wait on your current thread to receive a message from a queue?

This may more be a problem with my understanding and a desire to use the technology in a way it is not intended to be used, but what I would like to do is combine the send and receive examples from the following Microsoft example so that you can send message(s) off to various queues, and be able to listen in and handle "replies" (just messages that you're listening to on a queue) and close the connection when you are done receiving messages.

Some pseudo-code here:

   // send message(s) that will be consumed by other processes / applications, and by doing so later on we will expect some messages back
   await SendMessagesAsync(numberOfMessages);

    var receivedMessages = 0;
    while (receivedMessages < numberOfMessages)
    {
        // there is no "ReceiveAsync" method, this is what I would be looking for
        Message message = await queueClient.ReceiveAsync(TimeSpan.FromSeconds(30));
        receivedMessages++;

        // do something with the message here
   }

   await queueClient.CloseAsync();

Is this possible or am I "doing it wrong"?

回答1:

In the new library ReceiveAsync method is available on MessageReceiver class:

var messageReceiver = new MessageReceiver(SBConnString, QueueName, ReceiveMode.PeekLock);
Message message = await messageReceiver.ReceiveAsync();

See a full example at Get started sending and receiving messages from Service Bus queues using MessageSender and MessageReceiver.

回答2:

In Microsoft.Azure.ServiceBus library, there is no such a thing calledReceiveAsync. In this, you can process or receive the message by using RegisterOnMessageHandlerAndReceiveMessages(). With this you can receive the message with an event. With this RegisterOnMessageHandlerAndReceiveMessages() like queueClient.RegisterMessageHandler(ReceiveOrProcessMessagesAsync, messageHandlerOptions); and you have to seprately create this event for receiveMessages, in our case it is ReceiveOrProcessMessagesAsync

static async Task ReceiveOrProcessMessagesAsync(Message message, CancellationToken token)
    {
        // Process the message
        Console.WriteLine($"Received message: SequenceNumber:{message.SystemProperties.SequenceNumber} Body:{Encoding.UTF8.GetString(message.Body)}");

        // Complete the message so that it is not received again.
        // This can be done only if the queueClient is created in ReceiveMode.PeekLock mode (which is default).
        await queueClient.CompleteAsync(message.SystemProperties.LockToken);

        // Note: Use the cancellationToken passed as necessary to determine if the queueClient has already been closed.
        // If queueClient has already been Closed, you may chose to not call CompleteAsync() or AbandonAsync() etc. calls 
       // to avoid unnecessary exceptions.
    }

and you refer the below link for know about Microsoft.Azure.ServiceBus https://docs.microsoft.com/en-us/azure/service-bus-messaging/service-bus-dotnet-get-started-with-queues