Question

我使用Polymer和polymer-cli构建了一个html / js应用程序（一个渐进式Web应用程序），以及用于缓存和离线的生成良好的服务工作者。

我想知道如何在新版本的应用程序可用时通知用户并邀请他重新启动浏览器。

任何想法？

修改

IO2016上的一次演讲，其中Eric Bidel谈论服务工作者并通知用户有关应用程序的新版本： https://youtu.be/__KvYxcIIm8?list=PLOU2XLYxmsILe6_eGvDN3GyiodoV3qNSC&t=1510

需要查看Google IO网络源代码

Answer 1

参考文献：

https://developers.google.com/web/fundamentals/instant-and-offline/service-worker/lifecycle

https://classroom.udacity.com/courses/ud899

// page script
document.addEventListener('DOMContentLoaded', function(){
    if ('serviceWorker' in navigator) {
        navigator.serviceWorker
        .register('/sw.js')
        .then(function(registration) {
            console.info('ServiceWorker registration successful with scope:', registration.scope);

           // if there's no controller, this page wasn't loaded
           // via a service worker, so they're looking at the latest version.
           // In that case, exit early
           if (!navigator.serviceWorker.controller) return;

           // if there's an updated worker already waiting, update
           if (registration.waiting) {
               console.info('show toast and upon click update...');
               registration.waiting.postMessage({ updateSw: true });
               return;
           }

           // if there's an updated worker installing, track its
           // progress. If it becomes "installed", update
           if (registration.installing) {
               registration.addEventListener('statechange', function(){
                   if (registration.installing.state == 'installed'){
                       console.info('show toast and upon click update...');
                       registration.installing.postMessage({ updateSw: true });
                       return;          
                   }
               });
           }

           // otherwise, listen for new installing workers arriving.
           // If one arrives, track its progress.
           // If it becomes "installed", update
           registration.addEventListener('updatefound', function(){
               let newServiceWorker = registration.installing;

               newServiceWorker.addEventListener('statechange', function() {
                   if (newServiceWorker.state == 'installed') {
                       console.info('show toast and upon click update...');
                       newServiceWorker.postMessage({ updateSw: true });           
                   }
               });
           });
        })
        .catch(function(error) {
            console.info('ServiceWorker registration failed:', error);
        });


      navigator.serviceWorker.addEventListener('controllerchange', function() {
          window.location.reload();
      });
    }

});

// sw script
self.addEventListener('message', function(e) {
    if (e.data.updateSw){
        self.skipWaiting();
    }
});

Answer 2

感谢IO团队..我们需要检查当前的服务工作者是否变得多余

// Check to see if the service worker controlling the page at initial load
// has become redundant, since this implies there's a new service worker with fresh content.
if (navigator.serviceWorker && navigator.serviceWorker.controller) {
   navigator.serviceWorker.controller.onstatechange = function(event) {
     if (event.target.state === 'redundant') {
       // Define a handler that will be used for the next io-toast tap, at which point it
       // be automatically removed.
       const tapHandler = function() {
         window.location.reload();
       };

       if (IOWA.Elements && IOWA.Elements.Toast &&
          IOWA.Elements.Toast.showMessage) {
            IOWA.Elements.Toast.showMessage(
            'A new version of this app is available.', tapHandler, 'Refresh',
            null, 0); // duration 0 indications shows the toast indefinitely.
       } else {
         tapHandler(); // Force reload if user never was shown the toast.
       }
     }
  };
}

使用浏览器服务工作者通知新的应用程序版本

2 个答案: