javascript - 当缓存优先策略中的内容发生变化时，网站不会更新

Question

我在我想要支持离线浏览的渐进式网络应用程序中使用缓存优先策略。我注意到离线浏览工作正常但是当我更新网站上的内容时，它仍然显示旧的东西。我不确定我的代码有什么问题因为我希望它在加载离线之前检查是否有更新内容。我有 ma​​nifest.json、Service-worker.js、Offlinepage.js 和 ma​​in.js。

这是我使用的service-worker.js代码:

      //service worker configuration
      'use strict';

      const
        version = '1.0.0',
        CACHE = version + '::PWA',
        offlineURL = '/offline/',
        installFilesEssential = [
         '/',
          '/manifest.json',
          '/theme/pizza/css/style.css',
           '/theme/pizza/css/font-awesome/font-awesome.css',
          '/theme/pizza/javascript/script.js',
          '/theme/pizza/javascript/offlinepage.js',
          '/theme/pizza/logo.png',
          '/theme/pizza/icon.png'
        ].concat(offlineURL),
        installFilesDesirable = [
          '/favicon.ico',
         '/theme/pizza/logo.png',
          '/theme/pizza/icon.png'
        ];

      // install static assets
      function installStaticFiles() {

        return caches.open(CACHE)
          .then(cache => {

            // cache desirable files
            cache.addAll(installFilesDesirable);

            // cache essential files
            return cache.addAll(installFilesEssential);

          });

      }
      // clear old caches
      function clearOldCaches() {

        return caches.keys()
          .then(keylist => {

            return Promise.all(
              keylist
                .filter(key => key !== CACHE)
                .map(key => caches.delete(key))
            );

          });

      }

      // application installation
      self.addEventListener('install', event => {

        console.log('service worker: install');

        // cache core files
        event.waitUntil(
          installStaticFiles()
          .then(() => self.skipWaiting())
        );

      });

      // application activated
      self.addEventListener('activate', event => {

        console.log('service worker: activate');

        // delete old caches
        event.waitUntil(
          clearOldCaches()
          .then(() => self.clients.claim())
        );

      });

      // is image URL?
      let iExt = ['png', 'jpg', 'jpeg', 'gif', 'webp', 'bmp'].map(f => '.' + f);
      function isImage(url) {

        return iExt.reduce((ret, ext) => ret || url.endsWith(ext), false);

      }


      // return offline asset
      function offlineAsset(url) {

        if (isImage(url)) {

          // return image
          return new Response(
            '<svg role="img" viewBox="0 0 400 300" xmlns="http://www.w3.org/2000/svg"><title>offline</title><path d="M0 0h400v300H0z" fill="#eee" /><text x="200" y="150" text-anchor="middle" dominant-baseline="middle" font-family="sans-serif" font-size="50" fill="#ccc">offline</text></svg>',
            { headers: {
              'Content-Type': 'image/svg+xml',
              'Cache-Control': 'no-store'
            }}
          );

        }
        else {

          // return page
          return caches.match(offlineURL);

        }

      }

      // application fetch network data
      self.addEventListener('fetch', event => {

        // abandon non-GET requests
        if (event.request.method !== 'GET') return;

        let url = event.request.url;

        event.respondWith(

          caches.open(CACHE)
            .then(cache => {

              return cache.match(event.request)
                .then(response => {

                  if (response) {
                    // return cached file
                    console.log('cache fetch: ' + url);
                    return response;
                  }

                  // make network request
                  return fetch(event.request)
                    .then(newreq => {

                      console.log('network fetch: ' + url);
                      if (newreq.ok) cache.put(event.request, newreq.clone());
                      return newreq;

                    })
                    // app is offline
                    .catch(() => offlineAsset(url));

                });

            })

        );

      });

Answer 1

将 ?[VERSION] 添加到链接的 src。

例如:

<script type="text/javascript" src="your_file.js?1500"></script>

每次更新代码时，只需在版本中添加一个数字即可。

实际上这是重复的问题 look here for other解决方案。