RabbitMQ Message Properties

Question

I have a code like this in RabbitMQ :

byte[] rawBytes = serialize(trxEntities);    
byte[] zipped = rawBytes;  
if (shouldBeCompress) {  
zipped = compressor.compress(rawBytes);  
}  
BasicProperties persistentBasic = MessageProperties.PERSISTENT_BASIC;  
channel.basicPublish("", queueName, persistentBasic, zipped);

As you see some of my messages should be compress along witch some others shouldn't.
Is there any way I could set any properties to tell the consumer that "hey! this is a zipped message" ?

PS. does "com.rabbitmq.client.AMQP.BasicProperties.BasicProperties(..., Map headers, ...)" help me? I mean could I set any parameter in BasicProperties.header ?

score 5 · Answer 1 · answered May 23 '12 at 19:16

I think you may add anything you like to the header. However, there is a field called "contentEncoding", which I think is better for this situation. You may just put "gzip", "deflate", or the compression algorithm in this field, take a look at this page for those encoding defined for HTTP: http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.5

score 2 · Answer 2 · answered Jun 17 '15 at 16:48

Yes you can!

We use the type field for specifying what message was sent (eg. USER_INFO, HEARTBEAT, etc.) and the contentEncoding field for specifying compression (if any):

AMQP.BasicProperties.Builder propsBuilder = new AMQP.BasicProperties.Builder();
propsBuilder.type(typeName);
if (compress)
{
  propsBuilder.contentEncoding("zip");
}
BasicProperties props = propsBuilder.build();
channel.basicPublish(targetExchange, "", true, props, data);

// and receiving works like this:
Delivery delivery = consumer.nextDelivery();
byte[] data = delivery.getBody();
BasicProperties props = delivery.getProperties();
String typeName = props.getType();
String replyToServerId = props.getReplyTo();
String contentEncoding = props.getContentEncoding();

score 1 · Answer 3 · edited May 23 '17 at 11:53

1

you could use a wrapper for it as:

    public class wrapper(){
    public boolean isZipped;
    public String serializedMessage;
}

and then serialize this message with Java Serializable Object to Byte Array

or you can use this code:

persistentBasic = persistentBasic.builder().headers(filter).build();

and put your appropriate filter in header.

edited May 23 '17 at 11:53

Community

1
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answered May 23 '12 at 10:10

mohsen Lzd

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score 0 · Answer 4 · answered May 23 '12 at 19:32

For the project that I'm working which uses RabbitMQ we use a header field to identify the content-type and content-encoding

For example, a plain-text message in a queue would read

{'type' : 'plaintext', 'encoding' : 'utf-8'}

Compressed data streams are processed through Base64 and then sent

{'type' : 'gzip', 'encoding' : 'base64'}

There is not a standardized mechanism with RabbitMQ to identify the content-type and encoding, you may adopt your own or select a commonly used standard.

Shouldn't type & encoding be similar to how it's used more broadly? i.e. http://stackoverflow.com/a/23600787/98069 — wbyoung, Mar 18 '17 at 17:05

RabbitMQ Message Properties

4 Answers4