Angular Service Worker 不适用于 iOS 独立模式

Question

我正在使用 Ionic v4 和 Angular PWA 服务工作者来开发 PWA。在 app.component.ts 上有一个注入服务来检查 PWA 上是否有可用的更新，然后下载并重新加载。

当我使用浏览器打开 PWA 时，服务运行良好，如果我部署更新，服务工作者会更新缓存的 PWA 并“自动重新加载”页面。

问题来自 PWA/独立模式，在 iOS 上，当 PWA 添加到主屏幕时，它不再刷新，甚至使用任务应用程序列表杀死它。只有当我关闭设备并再次打开时，它才会刷新应用程序的状态。在 Android 设备上，在 PWA 模式下一切正常。

这是我使用 Angular Service Worker 实现的版本检查器服务：

import {Injectable} from '@angular/core';
import {SwUpdate} from '@angular/service-worker';

@Injectable()
export class LogUpdateService {

    constructor(updates: SwUpdate) {
        console.warn('check')
        updates.available.subscribe(event => {
            console.log('current version is', event.current);
            console.log('available version is', event.available);
            updates.activateUpdate().then(() => {
                console.warn('downloaded')
                document.location.reload();
            });
        });
        updates.activated.subscribe(event => {
            console.log('old version was', event.previous);
            console.log('new version is', event.current);
        });
    }
}

这是我的 package.json：

"dependencies": {
    "@angular/common": "^7.2.9",
    "@angular/core": "^7.2.9",
    "@angular/forms": "^7.2.9",
    "@angular/http": "^7.2.9",
    "@angular/platform-browser": "^7.2.9",
    "@angular/platform-browser-dynamic": "^7.2.9",
    "@angular/pwa": "0.13.8",
    "@angular/router": "^7.2.9",
    "@angular/service-worker": "7.2.12",
    "@ionic-native/core": "^5.2.0",
    "@ionic-native/network": "^5.2.0",
    "@ionic-native/splash-screen": "^5.2.0",
    "@ionic-native/status-bar": "^5.2.0",
    "@ionic/angular": "4.2.0",
    "@ionic/storage": "^2.2.0",
    "@ngx-translate/core": "^11.0.1",
    "@ngx-translate/http-loader": "^4.0.0",
    "cordova-plugin-network-information": "2.0.1",
    "cordova-sqlite-storage": "3.2.0",
    "core-js": "^2.6.5",
    "ionic2-calendar": "^0.5.2",
    "moment": "^2.24.0",
    "rxjs": "~6.4.0",
    "serve": "^10.1.2",
    "zone.js": "~0.8.29"
  },
  "devDependencies": {
    "@angular-devkit/architect": "0.13.8",
    "@angular-devkit/build-angular": "0.13.8",
    "@angular-devkit/core": "7.3.8",
    "@angular-devkit/schematics": "7.3.8",
    "@angular/cli": "7.3.8",
    "@angular/compiler": "~7.2.9",
    "@angular/compiler-cli": "~7.2.9",
    "@angular/language-service": "~7.2.9",
    "@ionic/angular-toolkit": "1.5.0",
    "@types/jasmine": "~3.3.9",
    "@types/jasminewd2": "~2.0.6",
    "@types/node": "~11.11.3",
    "@ionic/lab": "1.0.24",
    "codelyzer": "~4.5.0",
    "jasmine-core": "~3.3.0",
    "jasmine-spec-reporter": "~4.2.1",
    "karma": "~4.0.1",
    "karma-chrome-launcher": "~2.2.0",
    "karma-coverage-istanbul-reporter": "~2.0.5",
    "karma-jasmine": "~2.0.1",
    "karma-jasmine-html-reporter": "^1.4.0",
    "protractor": "~5.4.2",
    "ts-node": "~8.0.3",
    "tslint": "~5.14.0",
    "typescript": "^3.1.6"
  },
  "description": "An Ionic project",
  "cordova": {
    "plugins": {
      "cordova-sqlite-storage": {},
      "cordova-plugin-network-information": {}
    }
  }

对这个问题有什么想法吗？

Answer 1

见：PWAs on iOS 12.2 beta: the good, the bad, and the "not sure yet if good"

Answer 2

我找到的唯一解决方案是编写一个 javascript 函数（例如 updateiOS()）来执行以下操作

1- 验证我们是否在 iOS 独立模式下运行（如果不是则不要继续）

2- 在服务器上检查新版本，如果发现新版本，则重新加载页面（确保此 https 请求未缓存！）

3- 将上次检查时间保存在变量中（例如 var lastCheckTime）

在我的主要 javascript 函数中，我将为“focus”事件创建一个侦听器，该侦听器将检查 now 和 lastCheckTime 之间的差异，如果超过 1 天，则调用 updateiOS()

到目前为止，焦点事件对我来说效果很好