Calling Python from JS

Pyloid is a Python-based desktop app framework that allows easy function calls between frontend (JavaScript) and backend (Python) via a Remote Procedure Call (RPC) system. This document explains how to call Python functions from JavaScript using Pyloid's RPC system.

1. Defining RPC Functions in Python

All RPC functions must be defined as asynchronous (async) functions and registered with the @rpc.method() decorator. Additionally, if you add ctx (context) as the first argument, you can access the current app and window objects.

from pyloid.rpc import PyloidRPC, RPCContext

rpc = PyloidRPC()

@rpc.method()
async def greet(name: str):
    return f"Hello, {name}!"

@rpc.method()
async def set_title(ctx: RPCContext, title: str):
    ctx.window.set_title(title)
    return "Title changed!"

In the example above, the greet function simply returns a greeting, and the set_title function changes the title of the current window. You can access the current window (ctx.window) through ctx.

2. Calling RPC Functions from JavaScript

On the frontend, you can use Pyloid's rpc.call method to call Python RPC functions. Just pass the function name and arguments.

import { rpc } from 'pyloid-js';

rpc.call('greet', { name: 'World' })
    .then(response => {
        console.log(response); // "Hello, World!"
    })
    .catch(error => {
        console.error('RPC call failed:', error);
    });

rpc.call('set_title', { title: 'New Window Title' })
    .then(response => {
        console.log(response); // "Title changed!"
    });

3. Notes

• All RPC functions must be defined as async and can freely use await internally.

• If you add ctx (RPCContext) as a function argument, you can access the app and window objects.

• You can call the function immediately from the frontend by just passing the function name and arguments.

• All GUI-related functions in Pyloid are designed to be thread-safe, so you can safely call them even if you're not on the main thread.