mongoose/examples/uart-bridge/web_root/main.js

'use strict';
import {Component, h, html, render, useEffect, useState, useRef} from './preact.min.js';

const Message = m => html`<span
  style="color: ${m.message.uart ? '#444' : '#373'};">
  ${m.message.data}
</span>`;

const App = function(props) {
  const [cfg, setCfg] = useState({tcp: {}, ws: {}, mqtt: {}});
  const [messages, setMessages] = useState([]);
  const [connected, setConnected] = useState(false);
  const [txt, setTxt] = useState('');
  const [ws, setWs] = useState(null);
  const [rx, setRx] = useState('');
  const [tx, setTx] = useState('');
  const [baud, setBaud] = useState('');
  const [tcpport, setTcpport] = useState(4001);
  const [wsport, setWsport] = useState(4002);
  const [mqtt, setMqtt] = useState('');

  // const tcp_port = cfg.tcp.split(':')[2] || 4001;
  // const ws_port = cfg.ws.split(':')[2] || 4002;

  const refresh = () => fetch('/api/config/get').then(r => r.json()).then(r => {
    setTx(r.tx), setRx(r.rx), setBaud(r.baud), setCfg(r);
    setTcpport(r.tcp.url.split(':')[2] || 4001);
    setWsport(r.ws.url.split(':')[2] || 4002);
    setMqtt(r.mqtt.url);
  });

  const watchWebsocket = function() {
    // Connect to websocker port, to implement WS console
    var reconnect = function() {
      var port;
      setWsport(x => port = x);
      var l = window.location, proto = l.protocol.replace('http', 'ws');
      var tid, url = `${proto}//${l.hostname}:${port}/ws`;
      // console.log(url);
      var ws = new WebSocket(url);
      ws.onopen = () => {
        setConnected(true);
        setWs(ws);
      };
      ws.onmessage = ev => {
        // console.log(ev, ev.data);
        setMessages(x => x.concat([{data: ev.data, uart: true}]));
      };
      ws.onclose = function() {
        clearTimeout(tid);
        tid = setTimeout(reconnect, 1000);
        setConnected(false);
        setWs(null);
      };
    };
    reconnect();
  };

  useEffect(() => {
    refresh();
    watchWebsocket();
  }, []);


  const sendmessage = ev => {
    setMessages(x => x.concat([{data: txt + '\n', uart: false}]));
    if (ws) ws.send(txt + '\n');
    setTxt('');
  };

  const onchange = ev => false;

  return html`
<div class="container">
  <h1 style="margin-bottom: 0;">UART \u27F7 network bridge </h1>
  <pre class="d-none">${JSON.stringify(cfg, null, 2)}</pre>
  <div class="row">
    <div class="col col-4">
      <h3>UART configuration</h3>
      <div class="d-flex pr-1 my-1">
        <label class="addon">UART TX pin</label>
        <input style="width: 5em;" value=${tx} onchange=${onchange}
          oninput=${ev => setTx(ev.target.value)} />
      </div><div class="d-flex pr-1 my-1">
        <label class="addon">UART RX pin</label>
        <input style="width: 5em;" value=${rx} onchange=${onchange}
          oninput=${ev => setRx(ev.target.value)} />
      </div><div class="d-flex pr-1 my-y">
        <label class="addon">UART Baud</label>
        <input style="width: 5em;" value=${baud} onchange=${onchange}
          oninput=${ev => setBaud(ev.target.value)} />
      </div>
    </div>
    <div class="col col-8">
      <h3>Network configuration</h3>
      <div class="d-flex my-1">
        <label class="addon">Local TCP port</label>
        <input style="min-width: 4em; flex: 1 100%;"
          value=${tcpport} onchange=${onchange}
          oninput=${ev => setTcpport(ev.target.value)} />
        <label class="ml-1 d-flex label"><input type="checkbox"
          checked=${cfg.tcp.enable} /> enable</label>
      </div><div class="d-flex my-1">
        <label class="addon">Local WS port</label>
        <input style="flex: 1 100%;"
          value=${wsport} onchange=${onchange}
          oninput=${ev => setWsport(ev.target.value)} />
        <label class="ml-1 d-flex label"><input type="checkbox"
          checked=${cfg.ws.enable} /> enable</label>
      </div><div class="d-flex my-1">
        <label class="addon">Remote MQTT</label>
        <input style="flex: 1 100%;"
          value=${mqtt} onchange=${onchange}
          oninput=${ev => setMqtt(ev.target.value)} />
        <label class="ml-1 d-flex label"><input type="checkbox"
          checked=${cfg.mqtt.enable} /> enable</label>
      </div>
    </div>
  </div>

  <div class="msg">
    Note: to connect over MQTT, 
      go to <a href="http://www.hivemq.com/demos/websocket-client/">
        console</a>, subscribe to b/tx and publish to b/rx<br/>
    Note: to connect over TCP, use netcat utility:<br/>
    $ nc ${location.hostname} ${tcpport}
  </div>

  <div style="margin-top: 2em;">
    <b>UART console</b><span style="margin-left: 1em; color: #777;">works 
    over the local WS port. WebSocket status: </span><span
      style="color: ${connected ? 'teal' : 'red'};">
      \u25cf ${connected ? 'connected' : 'disconnected'} </span>
  </div>
  <div style="margin: 0.5em 0; display: flex">
    <input placeholder="to send data, type and press enter..." style="flex: 1 100%;"
      value=${txt} onchange=${sendmessage}
      oninput=${ev => setTxt(ev.target.value)} />
    <button style="margin-left: 1em;"
      onclick=${ev => setMessages([])}>clear</button>
  </div>
  <pre style="height: 15em; overflow: auto;">
    ${messages.map(message => h(Message, {message}))}
  </pre>

</div>`;
};

window.onload = () => render(h(App), document.body);