MsgpackEmitter encodes byte[] as a base64 string

[chris-zen]

When writing an array of bytes Transit uses the BinaryWriteHandler which gives the b tag. Then for that tag, the AbstractEmitter calls the function emitBinary. Its implementation in MsgpackEmitter encodes the array of bytes as Base64 and emits an string as follows:

byte[] encodedBytes = Base64.encodeBase64((byte[])b);
emitString(Constants.ESC_STR, "b", new String(encodedBytes), asMapKey, cache);

Reading the specs of MessagePack I see that they have native support for encoding binary data without having to use strings encoded as Base64. I can understand this strategy for the JSON emitters but not for the Msgpack one.

[chris-zen]

I just realised that the Transit specs mandate to encode binary data as a base64 string. I don't really understand this decision, and makes me realise that using the MSGPACK format is not that much better than using the JSON one.

[puredanger]

FYI, there is more discussion of this here: cognitect/transit-format#2