green-screen-proxy

WebSocket-to-TCP proxy for green-screen-react. Bridges browser WebSocket connections to TN5250, TN3270, VT220, and HP 6530 hosts over TCP.

Install

npm install green-screen-proxy

Usage

npx green-screen-proxy              # Start on port 3001
npx green-screen-proxy --mock       # Mock mode (no real host needed)
npx green-screen-proxy --port 8080  # Custom port
npx green-screen-terminal           # Proxy + web terminal UI (separate package)

Mock mode

With --mock, the proxy serves mock terminal screens — useful for trying out the component without a real host connection.

Connecting to a real host

Without --mock, the proxy opens real TCP connections. The sign-in form in the React component collects host, port, protocol, and credentials — the proxy handles the rest.

Cloudflare Worker Deployment

Deploy a serverless proxy to Cloudflare Workers:

npx green-screen-proxy deploy                             # Default settings
npx green-screen-proxy deploy --name my-terminal          # Custom worker name
npx green-screen-proxy deploy --origins https://myapp.com # Lock CORS to your domain

This will:

1. Install Wrangler (Cloudflare CLI) if not present
2. Log you in to Cloudflare if needed
3. Deploy the worker and print the URL
4. Save the URL to .env.local (auto-detects Vite, Next.js, CRA)

Then point the React component at it:

const adapter = new WebSocketAdapter({
  workerUrl: 'https://green-screen-worker.your-subdomain.workers.dev'
});

Programmatic API

Start the proxy from your own Node.js app:

import { createProxy } from 'green-screen-proxy';

const proxy = await createProxy({ port: 3001 });
console.log(`Proxy running on port ${proxy.port}`);

// Later:
await proxy.close();

Options

| Option | Type | Default | Description | |--------|------|---------|-------------| | port | number | 3001 | Port to listen on | | mock | boolean | false | Use mock screens |

Returns

| Property | Type | Description | |----------|------|-------------| | server | HttpServer | The underlying HTTP server | | app | Express | The Express app (add your own middleware) | | port | number | The actual port (may differ if original was in use) | | close() | Promise<void> | Stop the server |

How It Works

  Browser                  Proxy                    Host
┌────────────┐        ┌────────────┐        ┌────────────┐
│ WebSocket  │  WS    │  Express   │  TCP   │  IBM i     │
│ client     │◄──────►│  :3001     │◄──────►│  Mainframe │
└────────────┘        └────────────┘        └────────────┘

The proxy manages sessions — each WebSocket connection gets its own TCP session to the target host. Screen data is parsed into a protocol-agnostic format and pushed to the client in real time.

License

MIT