RabbitTemplate.convertAndSend overrides MessageProperties

[digitalsanctum]

I'm having an issue where headers that I explicitly set on a Message object get overwritten. It seems you're forced to use a MessagePostProcessor in order to add headers to a message. As an example, the following method creates a new instance of RabbitMessageProperties in RabbitTemplate class:

public void convertAndSend(String exchange, String routingKey, final Object object) throws AmqpException {
		send(exchange, routingKey, new MessageCreator() {
			public Message createMessage() {
				return getRequiredMessageConverter().toMessage(object, new RabbitMessageProperties());
			}
		});
	}

This method is delegated to from the following method:

public void convertAndSend(String routingKey, final Object object) throws AmqpException {
		convertAndSend(this.exchange, routingKey, object);
	}

Since I passed in a Message object with the headers I needed, I expected message and headers to be present but the headers were lost because of the new instance of RabbitMessageProperties created on the delegate method. Here is my code that creates a message and the desired headers:

MessageProperties mProperties = new RabbitMessageProperties();
    mProperties.setHeader("bondId", request.getBondId());
    mProperties.setHeader("jobName", request.getJobName());
    mProperties.setHeader("filename", outputFile.getName());
    mProperties.setHeader("startTime", startTime);
    mProperties.setHeader("stopTime", stopTime);

    Message msg = new Message(outputFileBArray, mProperties);

    getRabbitTemplate().convertAndSend(request.getCallbackQueue(), msg);

Is this the desired behavior? If so, what's the best way to add user-defined headers to a message before sending it?

[Mark Fisher]

We've changed this quite a bit on the trunk version (for the upcoming M2 release). In fact, we now have methods that take a Message object directly, e.g.:

void send(Message message) throws AmqpException;

If you don't want to update to a snapshot dependency, then for M1 you could avoid the "convert" methods. Instead you can do something like this:

final Message someMessage = ...
template.send(new MessageCreator() {
    public Message createMessage() {
        return someMessage;
    }
});

[digitalsanctum]

Thanks again, Mark. Responsive and helpful as always.