Persist auth data across restarts

src/node/auth.js

@@ -64,13 +64,24 @@ export class StateWrapper {
 }
 
 export class Auth extends EventEmitter {
-  constructor({ adminUsername, adminPassword }) {
+  constructor({ adminUsername, adminPassword, persistData }) {
     super()
     this.adminUsername = adminUsername
     this.adminPassword = adminPassword
-    this.salt = rand62(16)
+    this.salt = persistData?.salt || rand62(16)
     this.tokensById = new Map()
     this.tokensByHash = new Map()
+    for (const token of persistData?.tokens ?? []) {
+      this.tokensById.set(token.id, token)
+      this.tokensByHash.set(token.tokenHash, token)
+    }
+  }
+
+  getPersistData() {
+    return {
+      salt: this.salt,
+      tokens: [...this.tokensById.values()],
+    }
   }
 
   getState() {

src/node/index.js

@@ -13,6 +13,7 @@ import {
   markDataSource,
   combineDataSources,
 } from './data'
+import * as persistence from './persistence'
 import { Auth, StateWrapper } from './auth'
 import StreamWindow from './StreamWindow'
 import TwitchBot from './TwitchBot'
@@ -195,6 +196,8 @@ async function main() {
       callback(false)
     })
 
+  const persistData = await persistence.load()
+
   const idGen = new StreamIDGenerator()
   let updateCustomStreams
   const customStreamData = new Repeater(async (push) => {
@@ -216,6 +219,7 @@ async function main() {
   const auth = new Auth({
     adminUsername: argv.control.username,
     adminPassword: argv.control.password,
+    persistData: persistData.auth,
   })
 
   let browseWindow = null
@@ -368,6 +372,7 @@ async function main() {
 
   auth.on('state', (authState) => {
     updateState({ auth: authState })
+    persistence.save({ auth: auth.getPersistData() })
   })
 
   const dataSources = [

src/node/persistence.js

@@ -0,0 +1,31 @@
+import { app } from 'electron'
+import { promises as fsPromises, stat } from 'fs'
+import path from 'path'
+import throttle from 'lodash/throttle'
+
+const stateFilePath = path.join(app.getPath('userData'), 'streamwall.json')
+
+let lastState = {}
+
+async function _save(partialState) {
+  const state = { ...lastState, ...partialState }
+  lastState = state
+  const data = JSON.stringify(state)
+  await fsPromises.writeFile(stateFilePath, data)
+}
+
+export const save = throttle(_save, 501)
+
+export async function load() {
+  try {
+    const data = await fsPromises.readFile(stateFilePath)
+    return JSON.parse(data)
+  } catch (err) {
+    if (err.code === 'ENOENT') {
+      // Ignore missing file.
+    } else {
+      console.warn('error reading persisted state:', err)
+    }
+    return {}
+  }
+}