Between hosts

Three things cross between hosts: a bundle of data, a program, and a running machine.

A bundle of data

Any OSC tool can send one to a host’s port. The command line receives on a UDP port it binds; this line waits for one packet, prints its payload and exits:

./o.se -f o.se.osen/osen.ose '/,/s/0.0.0.0' '/,/i/7788' '/!/udp/sock/bind' \
    '/!/udp/recv' '/!/drop' '/!/println' '/!/quit'

The board listens on UDP 8888 and answers whoever sent to it; the Python host’s examples/udp.py --serve 7777 is a responder to try against.

A program

Source, or already parsed: the parsed form needs only a machine at the far end, the source needs osen there too and is smaller on the wire.

• Command line: /!/load with a path takes a .ose or .osen file, or a shared library; a string of osen arrives as [/,/s/<source>, /!/repl/rep].
• Python: vm.parse(src) gives the bytes for a socket; ose.program(vm, src) marks them as a program when they define anything; vm.recv takes bytes in.
• Board: python3 tools/send_osen.py <address> '(1, 2) /o/add, /!/println' sends source to port 8888, as the one-message bundle the board expects.
• Max: a message into the object; instantiating o.se.o.<name> loads <name>.ose from the search path.
• Browser: whatever arrives on the page’s socket lands in the machine’s input.

A running machine

("host:port") /continue/at moves the running program to that address; the rest of it runs on the far side, and a name it bound before the move is still bound after it. Move a program between two shells shows it.

Transports

• UDP — every host but the browser: the command line (/udp/*, from o.se.udp), the board (8888 for a program, 8889 for a machine, replies on 8890), Max (udpreceive/udpsend), Python (udp.py). A datagram has a size limit, and a machine can be larger than it; the board’s transport cuts a packet over the limit into /chunk messages and the board reassembles them.
• TCP, SLIP-framed — o.se.tcp at the command line (/tcp/listen, /tcp/accept, /tcp/connect, /tcp/send, /tcp/recv), and the board’s ESP32S3ResumeTCP sketch on 8889. No size limit.

• WebSocket — tools/ws-bridge.js, a Node program in web.o.se’s tools/, carries datagrams to a browser tab as WebSocket frames and frames back out as datagrams, byte for byte.

  node tools/ws-bridge.js                          # udp 9999 in, ws 8080 out
  node tools/ws-bridge.js --to 192.168.1.101:8889  # and frames back, to there
  node tools/ws-bridge.js --udp 9999 --ws 8080 --to <host:port>
  

  Put ws://localhost:8080 in the page’s socket field and press Connect. One tab at a time.

• Serial — the board prints to its console at 115200 baud; no host takes a program over serial.

From → to

machine: a running machine crosses and continues; program: a bundle that runs at the far end; data: a bundle arrives as data; —: no transport both ends share.

Recipes

• Move a program between two shells
• Send a program to a board
• Send data to the command line
• A program from Python to the browser
• The browser and a board through the bridge

Overview · The hosts · Examples