private object DeserializeQueueMessage(CloudQueueMessage queueMsg, Type destType)
{
using (MemoryStream messageData = new MemoryStream(queueMsg.AsBytes))
{
try
{
long dataLength = messageData.Length;
object msgObject = this.dataSerializer.Deserialize(messageData, destType);
// If successful, verify whether or not we are dealing with a small message of type XElement or XDocument. This is because the de-serialization from these types
// will not reliably detect the serialized instances of LargeQueueMessageInfo and will return them as either XElement or XDocument.
if (CloudUtility.IsAllowedQueueMessageSize(dataLength) && (destType == typeof(XDocument) || destType == typeof(XElement)))
{
// Both XElement and XDocument share the same base class of type XNode, hence we can safely cast to this type.
XNode xmlMsgObject = msgObject as XNode;
if (xmlMsgObject != null)
{
using (XmlReader xmlReader = xmlMsgObject.CreateReader())
{
xmlReader.MoveToContent();
// If the first node's name matches the name of the LargeQueueMessageInfo type,
// we should treat this message as an instance of LargeQueueMessageInfo and perform de-serialization one more time.
if (String.Compare(xmlReader.Name, typeof(LargeQueueMessageInfo).Name, false) == 0)
{
messageData.Seek(0, SeekOrigin.Begin);
msgObject = this.dataSerializer.Deserialize(messageData, typeof(LargeQueueMessageInfo));
}
}
}
}
return(msgObject);
}
catch (SerializationException)
{
// Got a serialization exception, should reset the stream position.
messageData.Seek(0, SeekOrigin.Begin);
}
// Try to deserialize as LargeQueueMessageInfo.
return(this.dataSerializer.Deserialize(messageData, typeof(LargeQueueMessageInfo)));
}
}
/// <summary>
/// Puts a single message on a queue.
/// </summary>
/// <typeparam name="T">The type of the payload associated with the message.</typeparam>
/// <param name="queueName">The target queue name on which message will be placed.</param>
/// <param name="message">The payload to be put into a queue.</param>
public void Put <T>(string queueName, T message)
{
Guard.ArgumentNotNullOrEmptyString(queueName, "queueName");
Guard.ArgumentNotNull(message, "message");
// Obtain a reference to the queue by its name. The name will be validated against compliance with storage resource names.
var queue = this.queueStorage.GetQueueReference(CloudUtility.GetSafeContainerName(queueName));
CloudQueueMessage queueMessage = null;
// Allocate a memory buffer into which messages will be serialized prior to being put on a queue.
using (MemoryStream dataStream = new MemoryStream(Convert.ToInt32(CloudQueueMessage.MaxMessageSize)))
{
// Perform serialization of the message data into the target memory buffer.
this.dataSerializer.Serialize(message, dataStream);
// Reset the position in the buffer as we will be reading its content from the beginning.
dataStream.Seek(0, SeekOrigin.Begin);
// First, determine whether the specified message can be accommodated on a queue.
if (CloudUtility.IsAllowedQueueMessageSize(dataStream.Length))
{
queueMessage = new CloudQueueMessage(dataStream.ToArray());
}
else
{
// Create an instance of a large queue item metadata message.
LargeQueueMessageInfo queueMsgInfo = LargeQueueMessageInfo.Create(queueName);
// Persist the stream of data that represents a large message into the overflow message store.
this.overflowStorage.Put <Stream>(queueMsgInfo.ContainerName, queueMsgInfo.BlobReference, dataStream);
// Invoke the Put operation recursively to enqueue the metadata message.
Put <LargeQueueMessageInfo>(queueName, queueMsgInfo);
}
}
// Check if a message is available to be put on a queue.
if (queueMessage != null)
{
Put(queue, queueMessage);
}
}
