Question

I’m trying to find a way to pass objects to the Azure Queue. I couldn’t find a way to do this.

As I’ve seen I can pass string or byte array, which is not very comfortable for passing objects.

Is there anyway to pass custom objects to the Queue?

Thanks!

Answer 1

You can use the following classes as example:

 [Serializable]
    public abstract class BaseMessage
    {
        public byte[] ToBinary()
        {
            BinaryFormatter bf = new BinaryFormatter();
            byte[] output = null;
            using (MemoryStream ms = new MemoryStream())
            {
                ms.Position = 0;
                bf.Serialize(ms, this);
                output = ms.GetBuffer();
            }
            return output;
        }

        public static T FromMessage<T>(CloudQueueMessage m)
        {
            byte[] buffer = m.AsBytes;
            T returnValue = default(T);
            using (MemoryStream ms = new MemoryStream(buffer))
            {
                ms.Position = 0;
                BinaryFormatter bf = new BinaryFormatter();
                returnValue = (T)bf.Deserialize(ms);
            }
            return returnValue;
        }
    }

Then a StdQueue (a Queue that is strongly typed):

   public class StdQueue<T> where T : BaseMessage, new()
    {
        protected CloudQueue queue;

        public StdQueue(CloudQueue queue)
        {
            this.queue = queue;
        }

        public void AddMessage(T message)
        {
            CloudQueueMessage msg =
            new CloudQueueMessage(message.ToBinary());
            queue.AddMessage(msg);
        }

        public void DeleteMessage(CloudQueueMessage msg)
        {
            queue.DeleteMessage(msg);
        }

        public CloudQueueMessage GetMessage()
        {
            return queue.GetMessage(TimeSpan.FromSeconds(120));
        }
    }

Then, all you have to do is to inherit the BaseMessage:

[Serializable]
public class ParseTaskMessage : BaseMessage
{
    public Guid TaskId { get; set; }

    public string BlobReferenceString { get; set; }

    public DateTime TimeRequested { get; set; }
}

And make a queue that works with that message:

CloudStorageAccount acc;
            if (!CloudStorageAccount.TryParse(connectionString, out acc))
            {
                throw new ArgumentOutOfRangeException("connectionString", "Invalid connection string was introduced!");
            }
            CloudQueueClient clnt = acc.CreateCloudQueueClient();
            CloudQueue queue = clnt.GetQueueReference(processQueue);
            queue.CreateIfNotExist();
            this._queue = new StdQueue<ParseTaskMessage>(queue);

Hope this helps!