Question

I need to create a Bytebuffer like object in Ruby. Here is my example in JAVA

int ADD_BYTES_FOR_MSG_LENGTH = 4;

Integer messageBodySize = new Integer(messageBody.getBytes().length);
byte[] messageHeader = ByteBuffer.allocate(ADD_BYTES_FOR_MSG_LENGTH).putInt(messageBodySize).array();

messageToSend = new byte[messageHeader.length + messageBodySize];

System.arraycopy(messageHeader, 0, messageToSend, 0, messageHeader.length);
System.arraycopy(messageBody.getBytes(), 0, messageToSend, messageHeader.length, messageBodySize);

I create a message starting with 4 bytes where is located size of the message body part, and then the actual message. I have no idea how to do this in Ruby, so please help.

Answer 1

I did this for Steam Condenser using an extended version of StringIO.

Although I don’t use any put* methods, these could be easily implemented like for example:

class StringIO

  def put_int(i)
    write [i].pack('v')
  end

end

You may have a look at the code, the documentation of the original class and my extensions.