runtime.js

// Copyright (c) 2026 RobotWebTools Contributors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// rclnodejs/web demo — runtime side (rclnodejs/web runtime + the demo's
// ROS 2 nodes; named `runtime.js` to avoid being confused with the
// page-side `static.js`).
//
//   1. Source ROS 2 (`source /opt/ros/<distro>/setup.bash`)
//   2. From this folder run `node runtime.js`
//   3. In another shell run `node static.js` to host
//      `index.html` on http://localhost:8080/ — same split as the
//      TypeScript demo's `tsx server.ts` + `vite`.

'use strict';

const rclnodejs = require('../../../index.js');
// In a downstream project this is the public, supported import:
//   const { createRuntime, WebSocketTransport, HttpTransport } =
//     require('rclnodejs/web/server');
// Inside this in-repo demo we use the relative path so the file runs
// straight out of a fresh git clone, no `npm install` required.
const {
  createRuntime,
  WebSocketTransport,
  HttpTransport,
} = require('../../../lib/runtime');

const RUNTIME_PORT = Number(process.env.RUNTIME_PORT || 9000);
const HTTP_PORT = Number(process.env.HTTP_PORT || 9001);

function displayHost(host) {
  return host === '0.0.0.0' || host === '::' ? 'localhost' : host;
}

// Render the registry as a small human-readable table:
//   call       /add_two_ints       example_interfaces/srv/AddTwoInts
//   publish    /web_demo_chatter   std_msgs/msg/String
//   subscribe  /web_demo_tick      std_msgs/msg/String
function formatCapabilities(caps) {
  const rows = [];
  for (const verb of ['call', 'publish', 'subscribe']) {
    for (const [topic, type] of Object.entries(caps[verb] || {})) {
      rows.push([verb, topic, type]);
    }
  }
  if (rows.length === 0) return '  (none)';
  const w0 = Math.max(...rows.map((r) => r[0].length));
  const w1 = Math.max(...rows.map((r) => r[1].length));
  return rows
    .map(([v, t, ty]) => `  ${v.padEnd(w0)}  ${t.padEnd(w1)}  ${ty}`)
    .join('\n');
}

async function main() {
  // ---- Layer 1: rclnodejs core ----------------------------------------
  await rclnodejs.init();
  const node = rclnodejs.createNode('rclnodejs_web_demo_node');

  // A real ROS 2 service the browser can call.
  node.createService(
    'example_interfaces/srv/AddTwoInts',
    '/add_two_ints',
    (request, response) => {
      const reply = response.template;
      reply.sum = request.a + request.b;
      response.send(reply);
    }
  );

  // A real ROS 2 publisher producing a tick once a second so the
  // browser's subscribe() has something to receive without the user
  // having to publish first.
  const tickPub = node.createPublisher('std_msgs/msg/String', '/web_demo_tick');
  let counter = 0;
  setInterval(() => {
    tickPub.publish({
      data: `tick ${counter++} @ ${new Date().toISOString()}`,
    });
  }, 1000);

  rclnodejs.spin(node);

  // ---- Layer 2 + 3: capability runtime over WebSocket *and* HTTP -------
  // The same dispatcher / registry serves both transports — the L2 seam
  // is what proves the runtime is transport-agnostic. Browser SDK picks
  // a transport from the URL scheme; curl / Postman / AI agents use the
  // HTTP one directly.
  const runtime = createRuntime({
    node,
    transports: [
      new WebSocketTransport({
        port: RUNTIME_PORT,
        // '::' = dual-stack: accepts both IPv6 and IPv4-mapped
        // connections. Matches Node's http server default and avoids
        // the WSL2 / glibc "localhost → ::1" mismatch where
        // 0.0.0.0-only servers appear unreachable from the browser.
        host: '::',
      }),
      new HttpTransport({
        port: HTTP_PORT,
        host: '::',
      }),
    ],
  });
  runtime.expose({
    call: { '/add_two_ints': 'example_interfaces/srv/AddTwoInts' },
    publish: { '/web_demo_chatter': 'std_msgs/msg/String' },
    subscribe: {
      '/web_demo_tick': 'std_msgs/msg/String',
      '/web_demo_chatter': 'std_msgs/msg/String',
    },
  });
  await runtime.start();

  const caps = runtime.registry.list();
  const total =
    Object.keys(caps.call || {}).length +
    Object.keys(caps.publish || {}).length +
    Object.keys(caps.subscribe || {}).length;

  console.log('rclnodejs/web demo running (JavaScript)');
  console.log(
    `  WebSocket : ws://${displayHost('::')}:${RUNTIME_PORT}/capability`
  );
  console.log(
    `  HTTP      : http://${displayHost('::')}:${HTTP_PORT}/capability  (call / publish, curl-able)`
  );
  console.log();
  console.log(`Exposed capabilities (${total}):`);
  console.log(formatCapabilities(caps));
  console.log();
  console.log(
    'Static page: run `node static.js` in another shell, then open http://localhost:8080/'
  );

  // ---- Graceful shutdown ----------------------------------------------
  const stop = async () => {
    console.log('\nstopping…');
    await runtime.stop();
    rclnodejs.shutdown();
    process.exit(0);
  };
  process.once('SIGINT', stop);
  process.once('SIGTERM', stop);
}

main().catch((err) => {
  console.error(err);
  process.exit(1);
});