How to decode msgpack over TCP?

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On 16278: Unable to dissect UDP msgpack I found:

tshark -r - -T fields -e data udp.port==60003 | xxd -p -r | msgpack2json -c

Decoding a message to JSON needs 3 steps:

1. Output the msgpack from Wireshark as hexdata, which is easy for UDP as each message will be exactly one packet. How are the msgpack objects in your pcap file sent over TCP? Are they contained in one packet or are they segmented? And is there just one message per TCP stream or are there a sequence of messages? Are you able to share a pcap or is there sensitive information in it?
2. Transform the hex data back to raw (binary) data with xxd -p -r
3. Convert the binary msgpack data to JSON with msgpack2json
4. (optional) add a loop around the tshark command to process each message separately

So IMHO the biggest challenge is not converting to JSON, it's extracting each message out of the TCP stream(s) in your pcap file. It might be easy (if each msgpack message is one TCP segment) or can be hard (if there is a continuous stream of msgpack messages). That all depends on the way the messages are sent in your case.

There is a sample capture attached to 16278: Unable to dissect UDP msgpack

Right-click "Data" line in the Packet Details and set "Decode As..." to "msgpack".