其他分享
首页 > 其他分享> > PWA 实践/实战/应用(Google Workbox)

PWA 实践/实战/应用(Google Workbox)

作者:互联网

桌面端 PWA 应用:

桌面端 PWA 应用

移动端添加到桌面:

移动端添加到桌面

1 什么是 PWA

PWA(Progressive Web App - 渐进式网页应用)是一种理念,由 Google Chrome 在 2015 年提出。PWA 它不是特指某一项技术,而是应用多项技术来改善用户体验的 Web App,其核心技术包括 Web App ManifestService WorkerWeb Push 等,用户体验才是 PWA 的核心。

PWA 主要特点如下:

PWA 本身强调渐进式(Progressive),可以从两个角度来理解渐进式,首先,PWA 还在不断进化,Service Worker、Web App Manifest、Device API 等标准每年都会有不小的进步;其次,标准的设计向下兼容,并且侵入性小,开发者使用新特性代价很小,只需要在原有站点上新增,让站点的用户体验渐进式的增强。相关技术基准线:What makes a good Progressive Web App?

2 案例调研

2.1 米哈游 - 崩坏3

访问地址:https://bbs.mihoyo.com/bh3/

PWA:仅支持在 IOS 端添加到桌面。

2.2 阿里速卖通(AliExpress)

访问地址:https://m.aliexpress.com/

PWA:使用 Google Workbox(CDN)

  1. 支持添加到桌面,manifest
  2. 支持缓存,Service Worker

2.3 饿了么

访问地址:https://h5.ele.me/msite/#pwa=true

PWA:自研 - PWA 在饿了么的实践经验

  1. 支持添加到桌面,manifest
  2. 支持缓存和离线访问,Service Worker

2.4 Instagram

左边原生应用,右边 PWA

访问地址:https://www.instagram.com/

PWA:使用 Google Workbox

  1. 支持添加到桌面,manifest
  2. 支持缓存,Service Worker

2.5 Twitter

访问地址:https://mobile.twitter.com/home

PWA:Twitter 自研 - How we built Twitter Lite

  1. 支持添加到桌面,manifest
  2. 支持缓存和离线访问,Service Worker

除了正常的静态资源以外,Twitter 把首页也缓存了下来。

离线状态下有很好的用户体验,而不是显示默认的浏览器页面。

3 技术选型(Service Worker)

3.1 使用 Google Workbox 构建 Service Worker

3.1.1 什么是 Workbox

Workbox 是一组库,可以帮助开发者编写 Service Worker,通过 CacheStorage API 缓存资源。当一起使用 Service Worker 和 CacheStorage API 时,可以控制网站上使用的资源(HTML、CSS、JS、图像等)如何从网络或缓存中请求,甚至允许在离线时返回缓存的内容。

3.1.2 如何使用 Workbox

Workbox 是由许多 NPM 模块组成的。首先要从 NPM 中安装它,然后导入项目 Service Worker 所需的模块。Workbox 的主要特性之一是它的路由和缓存策略模块。

路由和缓存策略

Workbox 允许使用不同的缓存策略来管理 HTTP 请求的缓存。首先确定正在处理的请求是否符合条件,如果符合,则对其应用缓存策略。匹配是通过返回真值的回调函数进行的。缓存策略可以是 Workbox 的一种预定义策略,也可以创建自己的策略。如下是一个使用路由和缓存的基本 Service Worker。

import { registerRoute } from 'workbox-routing';
import {
  NetworkFirst,
  StaleWhileRevalidate,
  CacheFirst,
} from 'workbox-strategies';

// Used for filtering matches based on status code, header, or both
import { CacheableResponsePlugin } from 'workbox-cacheable-response';
// Used to limit entries in cache, remove entries after a certain period of time
import { ExpirationPlugin } from 'workbox-expiration';

// Cache page navigations (html) with a Network First strategy
registerRoute(
  // Check to see if the request is a navigation to a new page
  ({ request }) => request.mode === 'navigate',
  // Use a Network First caching strategy
  new NetworkFirst({
    // Put all cached files in a cache named 'pages'
    cacheName: 'pages',
    plugins: [
      // Ensure that only requests that result in a 200 status are cached
      new CacheableResponsePlugin({
        statuses: [200],
      }),
    ],
  }),
);

// Cache CSS, JS, and Web Worker requests with a Stale While Revalidate strategy
registerRoute(
  // Check to see if the request's destination is style for stylesheets, script for JavaScript, or worker for web worker
  ({ request }) =>
    request.destination === 'style' ||
    request.destination === 'script' ||
    request.destination === 'worker',
  // Use a Stale While Revalidate caching strategy
  new StaleWhileRevalidate({
    // Put all cached files in a cache named 'assets'
    cacheName: 'assets',
    plugins: [
      // Ensure that only requests that result in a 200 status are cached
      new CacheableResponsePlugin({
        statuses: [200],
      }),
    ],
  }),
);

// Cache images with a Cache First strategy
registerRoute(
  // Check to see if the request's destination is style for an image
  ({ request }) => request.destination === 'image',
  // Use a Cache First caching strategy
  new CacheFirst({
    // Put all cached files in a cache named 'images'
    cacheName: 'images',
    plugins: [
      // Ensure that only requests that result in a 200 status are cached
      new CacheableResponsePlugin({
        statuses: [200],
      }),
      // Don't cache more than 50 items, and expire them after 30 days
      new ExpirationPlugin({
        maxEntries: 50,
        maxAgeSeconds: 60 * 60 * 24 * 30, // 30 Days
      }),
    ],
  }),
);

这个 Service Worker 使用一个网络优先的策略来缓存导航请求(用于新的 HTML 页面),当它状态码为 200 时,该策略将缓存的页面存储在一个名为 pages 的缓存中。使用 Stale While Revalidate strategy 缓存 CSS、JavaScript 和 Web Worker,将缓存的资源存储在一个名为 assets 的缓存中。采用缓存优先的策略来缓存图像,将缓存的图像存储在名为 images 的缓存中,30 天过期,并且一次只允许 50 个。

预缓存

除了在发出请求时进行缓存(运行时缓存)之外,Workbox 还支持预缓存,即在安装 Service Worker 时缓存资源。有许多资源是非常适合预缓存的:Web 应用程序的起始 URL、离线回退页面以及关键的 JavaScript 和 CSS 文件。

使用一个支持预缓存清单注入的插件(webpack 或 rollup)来在新的 Service Worker 中使用预缓存。

import { precacheAndRoute } from 'workbox-precaching';

// Use with precache injection
precacheAndRoute(self.__WB_MANIFEST);

这个 Service Worker 将在安装时预缓存文件,替换 self.__WB_MANIFEST,其中包含在构建时注入到 Service Worker 中的资源。

离线回退

让 Web 应用在离线工作时感觉更健壮的常见模式是提供一个后退页面,而不是显示浏览器的默认错误页面。通过 Workbox 路由和预缓存,你可以在几行代码中设置这个模式。

import { precacheAndRoute, matchPrecache } from 'workbox-precaching';
import { setCatchHandler } from 'workbox-routing';

// Ensure your build step is configured to include /offline.html as part of your precache manifest.
precacheAndRoute(self.__WB_MANIFEST);

// Catch routing errors, like if the user is offline
setCatchHandler(async ({ event }) => {
  // Return the precached offline page if a document is being requested
  if (event.request.destination === 'document') {
    return matchPrecache('/offline.html');
  }

  return Response.error();
});

如果用户处于离线状态,则返回缓存的离线页面的内容,而不是生成一个浏览器错误。

有了 Workbox,可以利用 Service Worker 的力量来提高性能,并给您的站点提供独立于网络的优秀的用户体验。

3.2 自研 Service Worker

自研 Service Worker 更加灵活、可控,但是因为需要考虑到各种兼容,研发成本较高。

4 技术实践(Service Worker)

4.1 使用 CLI

安装 Workbox:

npm install workbox-cli -D

npx workbox --help

按照引导配置 workbox-config.js

npx workbox wizard

根据配置生成 Service Worker 程序:

npx workbox generateSW workbox-config.js

由于实际静态资源是挂载在 CDN 上面,需要修改预渲染资源的前缀

Workbox CLI - generateSW - Configuration

// A transformation that prepended the origin of a CDN for any URL starting with '/assets/' could be implemented as:

const cdnTransform = async (manifestEntries) => {
  const manifest = manifestEntries.map(entry => {
    const cdnOrigin = 'https://example.com';
    if (entry.url.startsWith('/assets/')) {
      entry.url = cdnOrigin + entry.url;
    }
    return entry;
  });
  return {manifest, warnings: []};
};

更多缓存配置可查阅官方文档

4.2 使用 Webpack

安装:

npm install workbox-webpack-plugin --save-dev

Webpack 配置:

// Inside of webpack.config.js:
const WorkboxPlugin = require('workbox-webpack-plugin');
// Version info...
const id = `${page}-v${version}`;

module.exports = {
  // Other webpack config...

  plugins: [
    // Other plugins...

    // WIKI https://developers.google.com/web/tools/workbox/reference-docs/latest/module-workbox-webpack-plugin.GenerateSW#GenerateSW
    new WorkboxPlugin.GenerateSW({
        cacheId: `${id}-gsw`,
        // Do not precache images
        exclude: [/\.(?:png|jpg|jpeg|svg)$/, 'service-wroker.js'], // Page need refresh twice.
        // target dir
        swDest: `../dist/${page}/service-worker.js`,
        skipWaiting: true,
        clientsClaim: true,
        // Define runtime caching rules.
        // WIKI https://developers.google.com/web/tools/workbox/reference-docs/latest/module-workbox-build#.RuntimeCachingEntry
        // Example https://gist.github.com/jeffposnick/fc761c06856fa10dbf93e62ce7c4bd57
        runtimeCaching: [
          // icon images
          {
            // Match any request that ends with .png, .jpg, .jpeg or .svg.
            urlPattern: /^https:\/\/cdn.example.com\/platform/, // /\.(?:png|jpg|jpeg|svg)$/,
            // Apply a cache-first strategy.
            handler: 'CacheFirst',
            options: {
              // Use a custom cache name.
              cacheName: `${id}-icon-images`,
              // Only cache 50 images, and expire them after 30 days
              expiration: {
                maxEntries: 50
              },
              // Ensure that only requests that result in a 200 status are cached
              cacheableResponse: {
                statuses: [0, 200]
              }
            }
          },
          // note images & others
          {
            // Match any request that ends with .png, .jpg, .jpeg or .svg.
            urlPattern: /^https:\/\/image.example.com/, // /\.(?:png|jpg|jpeg|svg)$/,
            // Apply a cache-first strategy.
            handler: 'CacheFirst',
            options: {
              // Use a custom cache name.
              cacheName: `${id}-note-images`,
              // Only cache 50 images, and expire them after 30 days
              expiration: {
                maxEntries: 50,
                maxAgeSeconds: 60 * 60 * 24 * 30 // 30 Days
              },
              // Ensure that only requests that result in a 200 status are cached
              cacheableResponse: {
                statuses: [0, 200]
              }
            }
          }
        ]
      });
  ]
};

页面中触发 Service Work:

<script>
// Check that service workers are supported
if ('serviceWorker' in navigator) {
  // Use the window load event to keep the page load performant
  window.addEventListener('load', () => {
    navigator.serviceWorker.register('/service-worker.js');
  });
}
</script>

5 添加到桌面方案

5.1 manifest.json 配置

{
  "name": "不知不问",
  "short_name": "不知不问",
  "description": "yyds",
  "start_url": "/?entry_mode=standalone",
  "display": "standalone",
  "orientation": "portrait",
  "background_color": "#F3F3F3",
  "theme_color": "#F3F3F3",
  "icons": [
    {
      "src": "https://mazey.cn/fav/logo-dark-circle-32x32.png",
      "sizes": "32x32",
      "type": "image/png"
    },
    {
      "src": "https://mazey.cn/fav/logo-dark-circle-144x144.png",
      "sizes": "144x144",
      "type": "image/png"
    },
    {
      "src": "https://mazey.cn/fav/logo-dark-circle-152x152.png",
      "sizes": "152x152",
      "type": "image/png"
    },
    {
      "src": "https://mazey.cn/fav/logo-dark-circle-180x180.png",
      "sizes": "180x180",
      "type": "image/png"
    },
    {
      "src": "https://mazey.cn/fav/logo-dark-circle-192x192.png",
      "sizes": "192x192",
      "type": "image/png"
    },
    {
      "src": "https://mazey.cn/fav/logo-dark-circle-512x512.png",
      "sizes": "512x512",
      "type": "image/png"
    }
  ],
  "scope": "/"
}

5.2 <head> 配置

为网站配置开屏图片、状态栏等。

<!--Mazey's favicon begin-->
<link rel="shortcut icon" type="image/png" href="https://mazey.cn/fav/logo-dark-circle-transparent-144x144.png">
<link rel="icon" type="image/png" sizes="32x32" href="https://mazey.cn/fav/logo-dark-circle-transparent-32x32.png">
<link rel="apple-touch-icon" sizes="144x144" href="https://mazey.cn/fav/logo-dark-circle-144x144.png">
<link rel="apple-touch-icon" sizes="152x152" href="https://mazey.cn/fav/logo-dark-circle-152x152.png">
<link rel="apple-touch-icon" sizes="180x180" href="https://mazey.cn/fav/logo-dark-circle-180x180.png">
<link rel="apple-touch-icon" sizes="192x192" href="https://mazey.cn/fav/logo-dark-circle-192x192.png">
<link rel="apple-touch-icon" sizes="512x512" href="https://mazey.cn/fav/logo-dark-circle-512x512.png">
<!--Mazey's favicon end-->
<!--Mazey's pwa manifest.json-->
<link rel="manifest" href="/wp-content/themes/polestar/manifest.json">
<!-- 开机图片 - begin -->
<!-- iPhone Xs Max (1242px × 2688px) -->
<link rel="apple-touch-startup-image" media="(device-width: 414px) and (device-height: 896px) and (-webkit-device-pixel-ratio: 3)" href="https://i.mazey.net/asset/read/cat-lovers-1242x2688.jpg" sizes="1242x2688">
<!-- iPhone Xr (828px x 1792px) -->
<link rel="apple-touch-startup-image" media="(device-width: 414px) and (device-height: 896px) and (-webkit-device-pixel-ratio: 2)" href="https://i.mazey.net/asset/read/cat-lovers-828x1792.jpg" sizes="828x1792">
<!-- iPhone X, Xs (1125px x 2436px) -->
<link rel="apple-touch-startup-image" media="(device-width: 375px) and (device-height: 812px) and (-webkit-device-pixel-ratio: 3)" href="https://i.mazey.net/asset/read/cat-lovers-1125x2436.jpg" sizes="1125x2436">
<!-- iPhone 8, 7, 6s, 6 (750px x 1334px) -->
<link rel="apple-touch-startup-image" media="(device-width: 375px) and (device-height: 667px) and (-webkit-device-pixel-ratio: 2)" href="https://i.mazey.net/asset/read/cat-lovers-750x1334.jpg" sizes="750x1334">
<!-- iPhone 8 Plus, 7 Plus, 6s Plus, 6 Plus (1242px x 2208px) -->
<link rel="apple-touch-startup-image" media="(device-width: 414px) and (device-height: 736px) and (-webkit-device-pixel-ratio: 3)" href="https://i.mazey.net/asset/read/cat-lovers-1242x2208.jpg" sizes="1242x2208">
<!-- iPhone 5 (640px x 1136px) -->
<link rel="apple-touch-startup-image" media="(device-width: 320px) and (device-height: 568px) and (-webkit-device-pixel-ratio: 2)" href="https://i.mazey.net/asset/read/cat-lovers-640x1136.jpg" sizes="640x1136">
<!-- 开机图片 - end -->
<!-- Touch Bar区域显示的网站图标 -->
<link rel="mask-icon" href="https://mazey.cn/fav/logo-dark-circle.svg" color="#F3F3F3">
<!-- 主题色 = manifest.json theme_color -->
<meta name="theme-color" content="#F3F3F3">
<meta name="apple-mobile-web-app-capable" content="yes">
<!-- 状态栏颜色 default/black/black-translucent -->
<meta name="apple-mobile-web-app-status-bar-style" content="black-translucent">
<!-- 应用名 -->
<meta name="apple-mobile-web-app-title" content="不知不问">
<!-- 在Windows 8上,我们可以将网站固定在开始屏幕上,而且支持个性化自定义色块icon和背景图片。这个标签是用来定义色块的背景图的。色块图应该为144*144像素的png格式图片,背景透明。 -->
<meta name="msapplication-TileImage" content="https://mazey.cn/fav/logo-dark-circle-transparent-144x144.png">
<!-- 同前一个元数据msapplication-TileImage类似,这个功能是用来设置颜色值,个性化自定义色块(磁贴)icon -->
<meta name="msapplication-TileColor" content="#F3F3F3">

开屏图片尺寸总结:

屏幕尺寸 倍数 图片尺寸
1024x1366(512x683) x2 2048x2732
834x1194(417x597) x2 1668x2388
768x1024(384x512) x2 1536x2048
834x1112(417x556) x2 1668x2224
810x1080 x2 1620x2160
428x926(214x463) x3 1284x2778
390x844 x3 1170x2532
375x812 x3 1125x2436
414x896 x3 1242x2688
414x896 x2 828x1792
414x736 x3 1242x2208
375x667 x2 750x1334
320x568 x2 640x1136

版权声明

本博客所有的原创文章,作者皆保留版权。转载必须包含本声明,保持本文完整,并以超链接形式注明作者后除和本文原始地址:https://blog.mazey.net/2675.html

(完)

标签:Google,Service,Worker,缓存,https,PWA,Workbox,workbox,png
来源: https://www.cnblogs.com/mazey/p/15986551.html