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!
Extension method that uses Newtonsoft.Json and async
public static async Task AddMessageAsJsonAsync<T>(this CloudQueue cloudQueue, T objectToAdd)
{
var messageAsJson = JsonConvert.SerializeObject(objectToAdd);
var cloudQueueMessage = new CloudQueueMessage(messageAsJson);
await cloudQueue.AddMessageAsync(cloudQueueMessage);
}
I like this generalization approach but I don't like having to put Serialize attribute on all the classes I might want to put in a message and derived them from a base (I might already have a base class too) so I used...
using System;
using System.Text;
using Microsoft.WindowsAzure.Storage.Queue;
using Newtonsoft.Json;
namespace Example.Queue
{
public static class CloudQueueMessageExtensions
{
public static CloudQueueMessage Serialize(Object o)
{
var stringBuilder = new StringBuilder();
stringBuilder.Append(o.GetType().FullName);
stringBuilder.Append(':');
stringBuilder.Append(JsonConvert.SerializeObject(o));
return new CloudQueueMessage(stringBuilder.ToString());
}
public static T Deserialize<T>(this CloudQueueMessage m)
{
int indexOf = m.AsString.IndexOf(':');
if (indexOf <= 0)
throw new Exception(string.Format("Cannot deserialize into object of type {0}",
typeof (T).FullName));
string typeName = m.AsString.Substring(0, indexOf);
string json = m.AsString.Substring(indexOf + 1);
if (typeName != typeof (T).FullName)
{
throw new Exception(string.Format("Cannot deserialize object of type {0} into one of type {1}",
typeName,
typeof (T).FullName));
}
return JsonConvert.DeserializeObject<T>(json);
}
}
}
e.g.
var myobject = new MyObject();
_queue.AddMessage( CloudQueueMessageExtensions.Serialize(myobject));
var myobject = _queue.GetMessage().Deserialize<MyObject>();
In case the storage queue is used with WebJob or Azure function (quite common scenario) then the current Azure SDK allows to use POCO object directly. See examples here:
Note: The SDK will automatically use Newtonsoft.Json for serialization/deserialization under the hood.
I liked @Akodo_Shado's approach to serialize with Newtonsoft.Json. I updated it for Azure.Storage.Queues and also added a "Retrieve and Delete" method that deserializes the object from the queue.
public static class CloudQueueExtensions
{
public static async Task AddMessageAsJsonAsync<T>(this QueueClient queueClient, T objectToAdd) where T : class
{
string messageAsJson = JsonConvert.SerializeObject(objectToAdd);
BinaryData cloudQueueMessage = new BinaryData(messageAsJson);
await queueClient.SendMessageAsync(cloudQueueMessage);
}
public static async Task<T> RetreiveAndDeleteMessageAsObjectAsync<T>(this QueueClient queueClient) where T : class
{
QueueMessage[] retrievedMessage = await queueClient.ReceiveMessagesAsync(1);
if (retrievedMessage.Length == 0) return null;
string theMessage = retrievedMessage[0].MessageText;
T instanceOfT = JsonConvert.DeserializeObject<T>(theMessage);
await queueClient.DeleteMessageAsync(retrievedMessage[0].MessageId, retrievedMessage[0].PopReceipt);
return instanceOfT;
}
}
The RetreiveAndDeleteMessageAsObjectAsync is designed to process 1 message at time, but you could obviously rewrite to deserialize the full array of messages and return a ICollection<T> or similar.
