Headers And Binary

Headers are sent with HPUB. Header messages received from the server are parsed from HMSG.

headers = {"traceparent" => "00-4bf92f3577b34da6a3ce929d0e0e4736-00f067aa0ba902b7-00"}
payload = "\x00frame\xFF".b

client.subscribe("tcp.frames") do |message|
  puts message.headers["traceparent"]
  puts message.data.bytesize
end

client.publish("tcp.frames", payload, headers: headers)

Header reads

Header keys preserve their received casing, and reads are case-insensitive:

message.headers["traceparent"]
message.headers["TraceParent"]

Repeated headers are stored as arrays.

Binary payloads

Payload size is computed with bytesize, and the payload is written separately from the protocol line. This keeps NUL bytes and non-UTF-8 bytes intact.

payload = "\x00\x01\xFF".b
client.publish("frames.raw", payload)

Headers and binary payloads can be used together.