1 line
4.4 KiB
JavaScript
1 line
4.4 KiB
JavaScript
"use strict";const OFFLINE_DATA_FILE="offline.js",CACHE_NAME_PREFIX="c2offline",BROADCASTCHANNEL_NAME="offline",CONSOLE_PREFIX="[SW] ",LAZYLOAD_KEYNAME="",broadcastChannel="undefined"==typeof BroadcastChannel?null:new BroadcastChannel("offline");function PostBroadcastMessage(e){broadcastChannel&&setTimeout(()=>broadcastChannel.postMessage(e),3e3)}function Broadcast(e){PostBroadcastMessage({type:e})}function BroadcastDownloadingUpdate(e){PostBroadcastMessage({type:"downloading-update",version:e})}function BroadcastUpdateReady(e){PostBroadcastMessage({type:"update-ready",version:e})}function IsUrlInLazyLoadList(e,t){if(!t)return!1;try{for(const a of t)if(new RegExp(a).test(e))return!0}catch(e){console.error(CONSOLE_PREFIX+"Error matching in lazy-load list: ",e)}return!1}function WriteLazyLoadListToStorage(e){return"undefined"==typeof localforage?Promise.resolve():localforage.setItem(LAZYLOAD_KEYNAME,e)}function ReadLazyLoadListFromStorage(){return"undefined"==typeof localforage?Promise.resolve([]):localforage.getItem(LAZYLOAD_KEYNAME)}function GetCacheBaseName(){return CACHE_NAME_PREFIX+"-"+self.registration.scope}function GetCacheVersionName(e){return GetCacheBaseName()+"-v"+e}async function GetAvailableCacheNames(){const e=await caches.keys(),t=GetCacheBaseName();return e.filter(e=>e.startsWith(t))}async function IsUpdatePending(){return(await GetAvailableCacheNames()).length>=2}async function GetMainPageUrl(){const e=await clients.matchAll({includeUncontrolled:!0,type:"window"});for(const t of e){let e=t.url;if(e.startsWith(self.registration.scope)&&(e=e.substring(self.registration.scope.length)),e&&"/"!==e)return e.startsWith("?")&&(e="/"+e),e}return""}function fetchWithBypass(e,t){if("string"==typeof e&&(e=new Request(e)),t){const t=new URL(e.url);return t.search+=Math.floor(1e6*Math.random()),fetch(t,{headers:e.headers,mode:e.mode,credentials:e.credentials,redirect:e.redirect,cache:"no-store"})}return fetch(e)}async function CreateCacheFromFileList(e,t,a){const n=await Promise.all(t.map(e=>fetchWithBypass(e,a)));let o=!0;for(const e of n)e.ok||(o=!1,console.error(CONSOLE_PREFIX+"Error fetching '"+e.url+"' ("+e.status+" "+e.statusText+")"));if(!o)throw new Error("not all resources were fetched successfully");const r=await caches.open(e);try{return await Promise.all(n.map((e,a)=>r.put(t[a],e)))}catch(t){throw console.error(CONSOLE_PREFIX+"Error writing cache entries: ",t),caches.delete(e),t}}async function UpdateCheck(e){try{const t=await fetchWithBypass(OFFLINE_DATA_FILE,!0);if(!t.ok)throw new Error(OFFLINE_DATA_FILE+" responded with "+t.status+" "+t.statusText);const a=await t.json(),n=a.version,o=a.fileList,r=a.lazyLoad,s=GetCacheVersionName(n);if(await caches.has(s))return void(await IsUpdatePending()?(console.log(CONSOLE_PREFIX+"Update pending"),Broadcast("update-pending")):(console.log(CONSOLE_PREFIX+"Up to date"),Broadcast("up-to-date")));const i=await GetMainPageUrl();o.unshift("./"),i&&-1===o.indexOf(i)&&o.unshift(i),console.log(CONSOLE_PREFIX+"Caching "+o.length+" files for offline use"),e?Broadcast("downloading"):BroadcastDownloadingUpdate(n),r&&await WriteLazyLoadListToStorage(r),await CreateCacheFromFileList(s,o,!e),await IsUpdatePending()?(console.log(CONSOLE_PREFIX+"All resources saved, update ready"),BroadcastUpdateReady(n)):(console.log(CONSOLE_PREFIX+"All resources saved, offline support ready"),Broadcast("offline-ready"))}catch(e){console.warn(CONSOLE_PREFIX+"Update check failed: ",e)}}async function GetCacheNameToUse(e,t){if(1===e.length||!t)return e[0];if((await clients.matchAll()).length>1)return e[0];const a=e[e.length-1];return console.log(CONSOLE_PREFIX+"Updating to new version"),await Promise.all(e.slice(0,-1).map(e=>caches.delete(e))),a}async function HandleFetch(e,t){const a=await GetAvailableCacheNames();if(!a.length)return fetch(e.request);const n=await GetCacheNameToUse(a,t),o=await caches.open(n),r=await o.match(e.request);if(r)return r;const s=await Promise.all([fetch(e.request),ReadLazyLoadListFromStorage()]),i=s[0],c=s[1];if(IsUrlInLazyLoadList(e.request.url,c))try{await o.put(e.request,i.clone())}catch(t){console.warn(CONSOLE_PREFIX+"Error caching '"+e.request.url+"': ",t)}return i}self.addEventListener("install",e=>{e.waitUntil(UpdateCheck(!0).catch(()=>null))}),self.addEventListener("fetch",e=>{if(new URL(e.request.url).origin!==location.origin)return;const t="navigate"===e.request.mode,a=HandleFetch(e,t);t&&e.waitUntil(a.then(()=>UpdateCheck(!1))),e.respondWith(a)}); |