jrpc-oo

Expose objects over the network using the JSON-RPC 2.0 protocol. This repository provides implementations in Node.js, LitElement (Web Components), and Python, allowing seamless RPC communication between different platforms.

Table of Contents

• Features
• Implementations
  • Node.js
  • LitElement (Web Components)
  • Python
• RPC Calling Pattern
• Example Usage
  • Node.js Server Example
  • Browser Client Example
  • Python Example
• Getting Started
• Integration
• Security
• License

Features

• JSON-RPC 2.0 protocol implementation
• WebSocket-based communication
• Bidirectional RPC calls:
  • Server can call client methods
  • Client can call server methods
  • Enables true peer-to-peer communication
• Multiple language support:
  • Node.js server and client
  • LitElement web components for browser integration
  • Python server and client
• Automatic function exposure and remote execution
• Secure WebSocket support (WSS)
• Bidirectional communication

Implementations

Node.js

• Server implementation in JRPCServer.js
• Client implementation in JRPCNodeClient.js
• Support for automatic class method exposure
• WebSocket-based communication

LitElement (Web Components)

• Browser-based client implementation in jrpc-client.js
• Material Design components integration
• Automatic UI generation for exposed methods
• WebSocket client capabilities

Python

• Server implementation in python/jrpc_server.py
• Client implementation in python/jrpc_client.py
• Compatible with Node.js and browser clients
• Async/await support using websockets

RPC Calling Pattern

All implementations (Node.js, Python, and Browser) use the same consistent pattern for making RPC calls:

// Standard RPC calling pattern
jrpcObject['ClassName.methodName'](arg1, arg2, ...)

// Examples:
// JavaScript/Browser
client['Calculator.add'](2, 3)
  .then(result => console.log(result))
  .catch(error => console.error(error));

// Python (with async/await)
result = await client['Calculator.add'](2, 3)

// Node.js
client['TestClass.fn2'](arg1, arg2)
  .then(result => console.log(result))
  .catch(error => console.error(error));

This consistent pattern ensures that RPC calls work the same way across all implementations, making it easier to:

• Switch between different implementations
• Write cross-platform code
• Understand and maintain the codebase

Example Usage

Node.js Server Example

JRPCServer = require('./JRPCServer');

class TestClass {
  fn2(arg1, arg2){
    console.log('fn2');
    console.log('arg1 :', JSON.stringify(arg1, null, 2));
    console.log('arg2 :', JSON.stringify(arg2, null, 2));
    return arg1;
  }
}

let tc = new TestClass;
var JrpcServer = new JRPCServer.JRPCServer(9000); // start a server on port 9000
JrpcServer.addClass(tc); // setup the class for remote use

Browser Client Example (LitElement)

import {JRPCClient} from '../jrpc-client.js';
import {html} from 'lit';
import '@material/mwc-button';

export class LocalJRPC extends JRPCClient {
  firstUpdated() {
    this.serverURI = "wss://0.0.0.0:9000";
  }

  render() {
    return html`
      <mwc-button raised
        @click=${this.testArgPass}
        >TestClass.fn2 arg test</mwc-button>
    `;
  }

  testArgPass() {
    this.call['TestClass.fn2'](1, {0: 'test', 1: [1, 2]})
      .then((result) => console.log(result))
      .catch((e) => console.error(e.message));
  }
}

window.customElements.define('local-jrpc', LocalJRPC);

Python Example

# Server
from python.jrpc_server import JRPCServer

class Calculator:
    def add(self, a, b):
        return {"result": a + b}

# Create the instance that will be resident on the server
calculator = Calculator()

# Create server and add the calculator instance
server = JRPCServer(host='localhost', port=8080)
server.add_instance(calculator)
server.start()

# Client
from python.jrpc_client import JRPCClient

client = JRPCClient('ws://localhost:8080')
result = await client['Calculator.add'](1, 2)
print(result)  # {"result": 3}

Getting Started

1. Install dependencies:

   npm install  # For Node.js/Browser
   pip install -r python/requirements.txt  # For Python

2. Start the server:

   # Node.js server
   ./JRPCServerTest.js
      
   # OR Python server
   python python/server.py

3. For web application demo:

   npm start

   Then:

   • Clear cert issues: visit https://0.0.0.0:9000
   • Access demo: https://0.0.0.0:8081

Integration

• See the jrpc-lit-node repo for Node.js/LitElement integration examples
• Python implementation can be integrated directly into any async Python application

Security

• Uses WSS (WebSocket Secure) for encrypted communication
• Certificate generation scripts included in repository
• Proper error handling and input validation

License

See LICENSE file for details.

run the webapp demo :

First install the requirements :

npm install

setup the nodejs side

./JRPCServerTest.js

setup the webapp

To setup run the webapp (answer defaults to the key generation question) :

npm start

Now clear cert issues in the browser go to the following url to clear the websocket port 9000 : https://0.0.0.0:9000

Now finally run the demo in the webapp : https://0.0.0.0:8081

in the webapp

You will see the class TestClass functions exposed as buttons. Press some buttons and look at the nodejs side/browser console to see function executions and returned arguments.

integrate into your apps

Have a look at the jrpc-lit-node repo for an example of integration.

run the nodejs demo :

First install the requirements :

npm install

run the server

./JRPCServerTest.js

run the clients in parallel and test

./tests/multiTest.sh