Message Compatibility with AMQP 0.9.x

[luizcarlosfaria]

Is your feature request related to a problem? Please describe.

Trying to publish with RabbitMQ.AMQP.Client 0.1.0 and 0.2.0-beta.0 and consume with regular RabbitMQ.Client, I've seen a prefix in message body.

How to produce the message:

 string text = JsonConvert.SerializeObject(message); //produces {"Text":"as","Seq":1,"Max":7000} 
 byte[] body = System.Text.Encoding.UTF8.GetBytes(text);
 IMessage amqpMessage = new AmqpMessage(body).ToAddress().Exchange(exchange).Key(routingKey).Build();
...
PublishResult result = await publisher.PublishAsync(message: amqpMessage, cancellationToken: cancellationToken).ConfigureAwait(configureAwait);

But when use Management to see what's is send (because consumers can't read this message) I've found some new behavior:

1. Message is sent as base64 (on amqp 0.9.x i can see {"Text":"test","Seq":1,"Max":7000} , but with amqp 1x it's a base64 version AFN3oSB7IlRleHQiOiJhcyIsIlNlcSI6MSwiTWF4Ijo3MDAwfQ==
2. When open this message a prefix cause add to body, you can see at https://dotnetfiddle.net/xd9qun

I've tryed to decode in some formats to understand:

Unicode (UTF-8): Sw� {"Text":"as","Seq":1,"Max":7000} 
Western European (ISO): Sw¡ {"Text":"as","Seq":1,"Max":7000} 
US-ASCII: Sw? {"Text":"as","Seq":1,"Max":7000} 
Unicode: 匀ꅷ笠吢硥≴∺獡Ⱒ匢煥㨢ⰱ䴢硡㨢〷〰� 
Unicode (Big-Endian): S瞡⁻≔數琢㨢慳∬≓敱∺ㄬ≍慸∺㜰〰� 
Unicode (UTF-8): Sw� {"Text":"as","Seq":1,"Max":7000} 
Unicode (UTF-7): Sw¡ {"Text":"as","Seq":1,"Max":7000} 

The base64 is easy to handle because the amqp message has type attribute.

But the prefix, I can't understand how handler

Describe the solution you'd like

• Verify if this is a default behavior or a bug.
• Explain how to handle this prefix (maybe defining a transport configuration).

Describe alternatives you've considered

No response

Additional context

No response

[Gsantomaggio]

Hi @luizcarlosfaria,
Thank you for reporting the issue. We will have a look as soon as possible.

[Gsantomaggio]

What you see as "Sw�" is:

0] = {byte} 0
[1] = {byte} 83 // TypeCodeSmallUlong
[2] = {byte} 119 // TypeCodeAMQPValue
[3] = {byte} // not relevant 

The AmqpValue type encoding added by the server: https://www.rabbitmq.com/docs/next/conversions#amqp-amqpl

PR #116 resolves the issue by changing the default from AMQPValue to ApplicationData, which is more appropriate for cross-protocol applications

[luizcarlosfaria]

Really thank you, @Gsantomaggio today I'll test it.

[luizcarlosfaria]

@Gsantomaggio last April 23, I've tested and it works!! Thank you.

[Gsantomaggio]

Great ! Thanks!