Add web-based remote control with HTTPS support

src/node/server.js

@@ -0,0 +1,120 @@
+import { app } from 'electron'
+import { promisify } from 'util'
+import path from 'path'
+import url from 'url'
+import http from 'http'
+import https from 'https'
+import simpleCert from 'node-simple-cert'
+import Koa from 'koa'
+import auth from 'koa-basic-auth'
+import route from 'koa-route'
+import serveStatic from 'koa-static'
+import views from 'koa-views'
+import websocket from 'koa-easy-ws'
+
+const webDistPath = path.join(app.getAppPath(), 'web')
+
+function initApp({ username, password, baseURL, getInitialState, onMessage }) {
+  const sockets = new Set()
+
+  const app = new Koa()
+
+  // silence koa printing errors when websockets close early
+  app.silent = true
+
+  app.use(auth({ name: username, pass: password }))
+  app.use(views(webDistPath, { extension: 'ejs' }))
+  app.use(serveStatic(webDistPath))
+  app.use(websocket())
+
+  app.use(
+    route.get('/', async (ctx) => {
+      await ctx.render('control', {
+        wsEndpoint: url.resolve(baseURL, 'ws').replace(/^http/, 'ws'),
+      })
+    }),
+  )
+
+  app.use(
+    route.get('/ws', async (ctx) => {
+      if (ctx.ws) {
+        const ws = await ctx.ws()
+        sockets.add(ws)
+
+        ws.on('close', () => {
+          sockets.delete(ws)
+        })
+
+        ws.on('message', (dataText) => {
+          let data
+          try {
+            data = JSON.parse(dataText)
+          } catch (err) {
+            console.warn('received unexpected ws data:', dataText)
+          }
+
+          try {
+            onMessage(data)
+          } catch (err) {
+            console.error('failed to handle ws message:', data, err)
+          }
+        })
+
+        const state = getInitialState()
+        ws.send(JSON.stringify({ type: 'state', state }))
+        return
+      }
+      ctx.status = 404
+    }),
+  )
+
+  const broadcastState = (state) => {
+    for (const ws of sockets) {
+      ws.send(JSON.stringify({ type: 'state', state }))
+    }
+  }
+
+  return { app, broadcastState }
+}
+
+export default async function initWebServer({
+  certDir,
+  email,
+  url: baseURL,
+  username,
+  password,
+  getInitialState,
+  onMessage,
+}) {
+  let { protocol, hostname, port } = new URL(baseURL)
+  if (!port) {
+    port = protocol === 'https' ? 443 : 80
+  }
+
+  const { app, broadcastState } = initApp({
+    username,
+    password,
+    baseURL,
+    getInitialState,
+    onMessage,
+  })
+
+  let server
+  if (protocol === 'https:') {
+    const { key, cert } = await simpleCert({
+      dataDir: certDir,
+      commonName: hostname,
+      email,
+      production: process.env.NODE_DEV === 'production',
+      serverHost: hostname,
+    })
+    server = https.createServer({ key, cert }, app.callback())
+  } else {
+    server = http.createServer(app.callback())
+  }
+
+  const listen = promisify(server.listen).bind(server)
+  await listen(port, hostname)
+
+  return { broadcastState }
+}