The message body cannot be read multiple times. To reuse it store the value after reading - azure

Question

I have created the code to get the Queue Client data using QueueClient.Receive() with Broken Message
BrokeredMessage deadmessage = client.Receive();
byte[] dataRaw = deadmessage.GetBody<byte[]>();
Due to some corrupted data, I got the exception on second line, while get the body of the broken message. So i was try to get the body of the message on catch block with SteamReader.
Stream stream = deadmessage.GetBody<Stream>();
StreamReader reader = new StreamReader(stream);
I experienced with below exception, Could anyone help me with appropriate fixes?
Exception details :
The message body cannot be read multiple times. To reuse it store the value after reading.

Answer 1

To take multiple attempts to read message body you need to read it as a stream first
serviceBusClient.GetBody<Stream>()
Then you can try to interpret it by different ways. For example it can be serialized directly by following way:
var brokeredMessage = new BrokeredMessage(message);
serviceBusClient.Send(brokeredMessage);
but it's better to serialize it to json first.
var brokeredMessage = new BrokeredMessage(JsonConvert.SerializeObject(message));
serviceBusClient.Send(brokeredMessage);
it's more safe in my view because json serialization ignores namespaces of message type, so you will not break your process when you move class of message to another namespace.
Suppose you are starting to send and read messages serialized in json but some old messages can be still binary serialized. In this case you can use the following logic:
public static T DeserializeMessage<T>(BrokeredMessage brokeredMessage)
{
using (var stream = brokeredMessage.GetBody<Stream>())
using (var streamReader = new StreamReader(stream))
{
string bodyText = streamReader.ReadToEnd();
try
{
return JsonConvert.DeserializeObject<T>(bodyText);
}
catch (JsonReaderException)
{
stream.Position = 0;
var reader = XmlDictionaryReader.CreateBinaryReader(stream, XmlDictionaryReaderQuotas.Max);
var serializer = new DataContractSerializer(typeof(T));
var msgBody = (T)serializer.ReadObject(reader);
return msgBody;
}
}
}
If you need to try to deserialize the message as another type, catch System.Runtime.Serialization.SerializationException on serializer.ReadObject(reader).

Answer 2

As Sean Feldman mentioned that if message is corrupted, then it will be handled by dead-letter queue.
Service Bus queues and topic subscriptions provide a secondary sub-queue, called a dead-letter queue (DLQ). The dead-letter queue does not need to be explicitly created and cannot be deleted or otherwise managed independent of the main entity.
The purpose of the dead-letter queue is to hold messages that cannot be delivered to any receiver, or simply messages that could not be processed.
If you need to know how to create and user Service Bus Queue we can refer to get start with Service Bus queues
To reuse it store the value after reading.
If it be can be read correctly then we can store it messageid and vaule for reuse.
The DLQ is mostly similar to any other queue.
If it is corrupted data, we can get it from the dead-letter queue as mormal queue.
string connectionString = CloudConfigurationManager.GetSetting('Microsoft.ServiceBus.ConnectionString');
QueueClient Client = QueueClient.CreateFromConnectionString(connectionString, deletLetterQueueName);
var message = Client.Receive(TimeSpan.FromSeconds(3));
if (message != null)
{
var ret = message.GetBody<stream>();
message.Complete();
}

Answer 3

I found another reason of the exception. The thing is that when I debugged different problem I got this exception. After some experiments I realized that Visual Studio reads the message behind the scene to show it for example in Watch panel, and when my code tried to get the message it was already read by Visual Studio.
To avoid this it needs to wrap the message to a property with backing field, which will store the value. And then I realized that the exception message abstracly says to make this.
So you should consider that it can be read behind the scene