sw.js

'use strict';

/**
 * Service Worker of PWA
 * To learn more and add one to your website, visit - https://PWA.com
 */

const cacheName = 'pwa-chace';
const offlinePage = self.location.protocol + '//' + self.location.host + '/';
const filesToCache = [
    '/',
    './index.php',
    './login.php',
    './about.php'
];
const neverCacheUrls = [/\/contao/, /\/contao-manager/, /intall/, /manifest.webmanifest /];



// Install
self.addEventListener('install', function (e) {
    console.log('PWA service worker installation');
    e.waitUntil(
        setTimeout(() => {
            addEventListener('message', event => {
                caches.open(cacheName).then(function (cache) {
                    console.log('PWA service worker caching dependencies');
                    event.data.map(function (url) {
                        return cache.add(url).catch(function (reason) {
                            //return console.log('PWA static Caching error: ' + reason + ' ' + url);
                        });
                    });
                })
            })
        }, 1000)
    );
});

//Activate and deleted old cached
self.addEventListener('activate', function (e) {
    console.log('PWA service worker activation');
    e.waitUntil(
        caches.keys().then(function (keyList) {
            return Promise.all(keyList.map(function (key) {
                if (key !== cacheName) {
                    console.log('PWA old cache removed', key);
                    return caches.delete(key);
                }
            }));
        })
    );
    return self.clients.claim();
});

// Fetch
self.addEventListener('fetch', function (e) {

    // Return if the current request url is in the never cache list
    if (!neverCacheUrls.every(checkNeverCacheList, e.request.url)) {
        console.log('PWA: Current request is excluded from cache.');
        return;
    }

    // Return if request url protocal isn't http or https
    if (!e.request.url.match(/^(http|https):\/\//i))
        return;

    // Return if request url is from an external domain.
    if (new URL(e.request.url).origin !== location.origin)
        return;
    // For POST requests, do not use the cache. Serve offline page if offline.
    if (e.request.method !== 'GET') {
        e.respondWith(
            fetch(e.request).catch(function () {
                return caches.match(e.request).then(res => res)
            })
        );
        return;
    }

    // Revving strategy
    if (e.request.mode === 'navigate' && navigator.onLine) {
        e.respondWith(
            fetch(e.request).then(function (response) {
                return caches.open(cacheName).then(function (cache) {
                    cache.put(e.request, response.clone());
                    return response;
                });
            })
        );
        return;
    }

    e.respondWith(
        caches.match(e.request).then(function (response) {
            return response || fetch(e.request).then(function (response) {
                return caches.open(cacheName).then(function (cache) {
                    cache.put(e.request, response.clone());
                    return response;
                });
            });
        }).catch(function () {
            return caches.match(e.request).then(res => res)
        })
    );
});

// Check if current url is in the neverCacheUrls list
function checkNeverCacheList(url) {
    if (this.match(url)) {
        return false;
    }
    return true;
}