Sending binary file through RabbitMQ

Question

I'm spec'ing a design right now that uses RabbitMQ as a message queue. The message are going to have a JSON body, and for one message in particular I'd like to add a small binary file.

What I'd like to know is, should the binary file's data be part of the JSON message, or can it be appended to the message separately?

Answer 1

Since RabbitMQ message payload is just a binary array you should encode your message body with 3 fields:

1. File size
2. Binary data of a file
3. Json

I disagree with a previous answer about embedding a file in json. If you encode file data inside of json you will get wasted space because of json escaping + unnecessary CPU usage because of json encoding/decoding of the file data + you will need to read file data twice (once for json deserialization and once more to copy it where it needs to go)