Question

我已将CRA升级到版本3.10.8，因为它内置了对PWA的支持。作为下一步，我在index.js中注册了我的服务工作者，我认为它已成功注册。现在我的主要目标是为我们的API调用（Rails中的后端）进行一些离线缓存，这样当没有网络时我可以提供缓存的响应。我还需要做些什么来提供缓存的API响应。当我使用Create react App构建我的应用程序时，它所做的就是创建一个名为的文件 registerServiceWorker.js然后从index.js调用它。

我们正在构建的最终应用程序与Codova打包在一起，因此大部分资产将在本地，我们的主要目的是缓存API调用。这是正确的方法吗？我们使用Redux进行状态管理，但截至目前还没有使用任何持久性。任何帮助/提示都将受到高度赞赏。

下面的registerServiceWorker.js代码......

    // In production, we register a service worker to serve assets from local cache.

// This lets the app load faster on subsequent visits in production, and gives
// it offline capabilities. However, it also means that developers (and users)
// will only see deployed updates on the "N+1" visit to a page, since previously
// cached resources are updated in the background.


const isLocalhost = Boolean(
  window.location.hostname === 'localhost' ||
    // [::1] is the IPv6 localhost address.
    window.location.hostname === '[::1]' ||
    // 127.0.0.1/8 is considered localhost for IPv4.
    window.location.hostname.match(
      /^127(?:\.(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)){3}$/
    )
);

export default function register() {
  if (process.env.NODE_ENV === 'production' && 'serviceWorker' in navigator) {
    // The URL constructor is available in all browsers that support SW.
    const publicUrl = new URL(process.env.PUBLIC_URL, window.location);
    if (publicUrl.origin !== window.location.origin) {
      // Our service worker won't work if PUBLIC_URL is on a different origin
      // from what our page is served on. This might happen if a CDN is used to
      // serve assets; see https://github.com/facebookincubator/create-react-app/issues/2374
      return;
    }

    window.addEventListener('load', () => {
      const swUrl = `${process.env.PUBLIC_URL}/service-worker.js`;

      if (!isLocalhost) {
        // Is not local host. Just register service worker
        registerValidSW(swUrl);
      } else {
        // This is running on localhost. Lets check if a service worker still exists or not.
        checkValidServiceWorker(swUrl);
      }
    });
  }
}

function registerValidSW(swUrl) {
  navigator.serviceWorker
    .register(swUrl)
    .then(registration => {
      registration.onupdatefound = () => {
        const installingWorker = registration.installing;
        installingWorker.onstatechange = () => {
          if (installingWorker.state === 'installed') {
            if (navigator.serviceWorker.controller) {
              // At this point, the old content will have been purged and
              // the fresh content will have been added to the cache.
              // It's the perfect time to display a "New content is
              // available; please refresh." message in your web app.
              console.log('New content is available; please refresh.');
            } else {
              // At this point, everything has been precached.
              // It's the perfect time to display a
              // "Content is cached for offline use." message.
              console.log('Content is cached for offline use.');
            }
          }
        };
      };
    })
    .catch(error => {
      console.error('Error during service worker registration:', error);
    });
}

function checkValidServiceWorker(swUrl) {
  // Check if the service worker can be found. If it can't reload the page.
  fetch(swUrl)
    .then(response => {
      // Ensure service worker exists, and that we really are getting a JS file.
      if (
        response.status === 404 ||
        response.headers.get('content-type').indexOf('javascript') === -1
      ) {
        // No service worker found. Probably a different app. Reload the page.
        navigator.serviceWorker.ready.then(registration => {
          registration.unregister().then(() => {
            window.location.reload();
          });
        });
      } else {
        // Service worker found. Proceed as normal.
        registerValidSW(swUrl);
      }
    })
    .catch(() => {
      console.log(
        'No internet connection found. App is running in offline mode.'
      );
    });
}

export function unregister() {
  if ('serviceWorker' in navigator) {
    navigator.serviceWorker.ready.then(registration => {
      registration.unregister();
    });
  }
}

Answer 1

我正在使用Create-react-app版本3。

更改条件语句，删除条件（process.env.NODE_ENV ==='production'&&），它应仅具有if（导航器中为'serviceWorker'）。

在公用文件夹中创建您的定制服务工作者文件，将以下代码作为const swUrl = {${process.env.PUBLIC_URL}/service-worker.js重写为swUrl = ./custom-service-worker.js。

在公用文件夹中的custom-service-worker.js文件中，添加以下代码，请参阅示例外部api调用（将您的api网址放置在缓存中）

        importScripts("https://storage.googleapis.com/workbox-cdn/releases/4.3.1/workbox-sw.js");

        if (workbox) {
                console.log('workbok loaded', workbox.routing)
        }

        //to cache the css html js and images files
        workbox.routing.registerRoute(
                /\.(?:js|html|css|images|svg)$/,
                new workbox.strategies.NetworkFirst()

        );
        workbox.routing.registerRoute(
                'http://localhost:3000',
                new workbox.strategies.NetworkFirst()
        );

        //to cache the external api calls
        workbox.routing.registerRoute(
                new RegExp('https://jsonplaceholder.typicode.com/users'),
                new workbox.strategies.StaleWhileRevalidate()
        );

        //to cache the external api calls
        workbox.routing.registerRoute(new RegExp('http://insight.dev.schoolwires.com/HelpAssets/C2Assets/C2Files/C2ImportUsersSample.csv'),
                new workbox.strategies.StaleWhileRevalidate()
        );

使用服务工作者创建React App

1 个答案: