Harmony: server and javascript improvements

[antirotor]

Changes

This PR changes how javascript functions are processed in Harmony and improves on socket server used for communication between python and Harmony.

Javascript changes

All code running inside Harmony is now seperated from Python code and reside in js folder in its own files. ESlint is configured there via node.js to help with development if needed. Just run npm install inside js directory to get everything set up. If your favorite IDE supports ESlint, it should pick up its configuration with all globals and style codes.

After avalon is installed in host, it will read AvalonHarmony.js and send it directly to Harmony.

AvalonHarmony is javascript namespace containing all functions called by Avalon API. Too add new function, just add it to AvalonHarmony namespace like:

AvalonHarmony.someNewFunction = function() {
      someNewFunctionality();
};

and call it from Python like:

from avalon.harmony.lib import send

send({"function", "AvalonHarmony.someNewFunction"})

you can also pass:

from pathlib import Path
from avalon.harmony.lib import send

js_file = Path("/some/path/to/some.js")
send({"script",  js_file.read_text()})

and that will pass whole script file to Harmony and evaluate it in global scope.

Server changes

Server/client now uses stricter protocol to handle communication. This was necessary because there was no precise control over data passed between server/client. Now, each message is prepended with 6 bytes:

| A | H | 0x00 | 0x00 | 0x00 | 0x00 | ...

First two bytes are magic bytes stands for Avalon Harmony. Next four bytes hold length of the message ... encoded as 32bit unsigned integer. This way we know how many bytes to read from the socket and if we need more or we need to parse multiple messages.

Related

Python code was changed to be more Python 3 like.

🏴 Related PR pending: ynput/OpenPype#666

[mkolar]

I'm getting syntax error after opening harmony but can't see what is wrong with it to be honest.

[antirotor]

I'm getting syntax error after opening harmony but can't see what is wrong with it to be honest.

problem is request.function vs request["function"]. Obviously some namespace clash again. Should be fixed now.