366 lines
9.8 KiB
TypeScript

// pack:ignore
// This is the service worker for notify.moe.
// When installed, it will intercept all requests made by the browser
// and return a cache-first response. By always returning cache first,
// we avoid latency problems on high latency connections like mobile
// networks. While the cache is being served, we start a real network
// request to the server to see if the resource changed. We compare the
// E-Tag of the cached and latest version of the resource. If the E-Tag
// of the current document changed, we send a message to the client
// that will cause the client to reload (diff) the page. It is not a real
// page reload as we will only calculate a DOM diff on the contents.
// If the style or script resources changed after being served, we need
// to force a real page reload.
const RELOADS = new Map<string, Promise<Response>>()
const ETAGS = new Map<string, string>()
const CACHEREFRESH = new Map<string, Promise<void>>()
const EXCLUDECACHE = new Set<string>([
// API requests
"/api/",
// PayPal stuff
"/paypal/",
// List imports
"/import/",
// Infinite scrolling
"/from/",
// Chrome extension
"chrome-extension",
// Authorization paths /auth/ and /logout are not listed here because they are handled in a special way.
])
class MyCache {
version: string
constructor(version: string) {
this.version = version
}
store(request: RequestInfo, response: Response) {
return caches.open(this.version).then(cache => {
return cache.put(request, response)
})
}
}
class MyServiceWorker {
cache: MyCache
constructor() {
this.cache = new MyCache("v-5")
self.addEventListener("install", (evt: InstallEvent) => evt.waitUntil(this.onInstall(evt)))
self.addEventListener("activate", (evt: any) => evt.waitUntil(this.onActivate(evt)))
self.addEventListener("fetch", (evt: FetchEvent) => evt.waitUntil(this.onRequest(evt)))
self.addEventListener("message", (evt: any) => evt.waitUntil(this.onMessage(evt)))
self.addEventListener("push", (evt: PushEvent) => evt.waitUntil(this.onPush(evt)))
self.addEventListener("pushsubscriptionchange", (evt: any) => evt.waitUntil(this.onPushSubscriptionChange(evt)))
self.addEventListener("notificationclick", (evt: NotificationEvent) => evt.waitUntil(this.onNotificationClick(evt)))
}
onInstall(evt: InstallEvent) {
console.log("service worker install")
return (self as any).skipWaiting().then(() => {
return this.installCache()
})
}
onActivate(evt: any) {
console.log("service worker activate")
// Only keep current version of the cache and delete old caches
let cacheWhitelist = [this.cache.version]
let deleteOldCache = caches.keys().then(keyList => {
return Promise.all(keyList.map(key => {
if(cacheWhitelist.indexOf(key) === -1) {
return caches.delete(key)
}
}))
})
// Immediate claim helps us gain control over a new client immediately
let immediateClaim = (self as any).clients.claim()
return Promise.all([
deleteOldCache,
immediateClaim
])
}
onRequest(evt: FetchEvent) {
let request = evt.request as Request
// If it's not a GET request, fetch it normally
if(request.method !== "GET") {
return evt.respondWith(fetch(request))
}
// Clear cache on authentication and fetch it normally
if(request.url.includes("/auth/") || request.url.includes("/logout")) {
return evt.respondWith(caches.delete(this.cache.version).then(() => fetch(request)))
}
// Exclude certain URLs from being cached
for(let pattern of EXCLUDECACHE.keys()) {
if(request.url.includes(pattern)) {
return evt.respondWith(fetch(request))
}
}
// If the request included the header "X-CacheOnly", return a cache-only response.
// This is used in reloads to avoid generating a 2nd request after a cache refresh.
if(request.headers.get("X-CacheOnly") === "true") {
return evt.respondWith(this.fromCache(request))
}
// Start fetching the request
let refresh = fetch(request).then(response => {
let clone = response.clone()
// Save the new version of the resource in the cache
let cacheRefresh = this.cache.store(request, clone)
CACHEREFRESH.set(request.url, cacheRefresh)
return response
})
// Save in map
RELOADS.set(request.url, refresh)
// Forced reload
let servedETag = undefined
let onResponse = response => {
servedETag = response.headers.get("ETag")
ETAGS.set(request.url, servedETag)
return response
}
if(request.headers.get("X-Reload") === "true") {
return evt.respondWith(refresh.then(onResponse))
}
// Try to serve cache first and fall back to network response
let networkOrCache = this.fromCache(request).then(onResponse).catch(error => {
// console.log("Cache MISS:", request.url)
return refresh
})
return evt.respondWith(networkOrCache)
}
onMessage(evt: any) {
let message = JSON.parse(evt.data)
switch(message.type) {
case "loaded":
this.onDOMContentLoaded(evt, message.url)
break
}
}
// onDOMContentLoaded is called when the client sent this service worker
// a message that the page has been loaded.
onDOMContentLoaded(evt: any, url: string) {
let refresh = RELOADS.get(url)
let servedETag = ETAGS.get(url)
// If the user requests a sub-page we should prefetch the full page, too.
if(url.includes("/_/") && !url.includes("/_/search/")) {
var prefetch = true
for(let pattern of EXCLUDECACHE.keys()) {
if(url.includes(pattern)) {
prefetch = false
break
}
}
if(prefetch) {
this.prefetchFullPage(url)
}
}
if(!refresh || !servedETag) {
return Promise.resolve()
}
return refresh.then((response: Response) => {
// When the actual network request was used by the client, response.bodyUsed is set.
// In that case the client is already up to date and we don"t need to tell the client to do a refresh.
if(response.bodyUsed) {
return
}
// Get the ETag of the cached response we sent to the client earlier.
let eTag = response.headers.get("ETag")
// Update ETag
ETAGS.set(url, eTag)
// If the ETag changed, we need to do a reload.
if(eTag !== servedETag) {
return this.forceClientReloadContent(url, evt.source)
}
// Do nothing
return Promise.resolve()
})
}
prefetchFullPage(url: string) {
let fullPage = new Request(url.replace("/_/", "/"))
let fullPageRefresh = fetch(fullPage, {
credentials: "same-origin"
}).then(response => {
// Save the new version of the resource in the cache
let cacheRefresh = caches.open(this.cache.version).then(cache => {
return cache.put(fullPage, response)
})
CACHEREFRESH.set(fullPage.url, cacheRefresh)
return response
})
// Save in map
RELOADS.set(fullPage.url, fullPageRefresh)
}
onPush(evt: PushEvent) {
var payload = evt.data ? evt.data.json() : {}
return (self as any).registration.showNotification(payload.title, {
body: payload.message,
icon: payload.icon,
image: payload.image,
data: payload.link,
badge: "https://notify.moe/brand/64.png"
})
}
onPushSubscriptionChange(evt: any) {
return (self as any).registration.pushManager.subscribe(evt.oldSubscription.options)
.then(async subscription => {
console.log("send subscription to server...")
let rawKey = subscription.getKey("p256dh")
let key = rawKey ? btoa(String.fromCharCode.apply(null, new Uint8Array(rawKey))) : ""
let rawSecret = subscription.getKey("auth")
let secret = rawSecret ? btoa(String.fromCharCode.apply(null, new Uint8Array(rawSecret))) : ""
let endpoint = subscription.endpoint
let pushSubscription = {
endpoint,
p256dh: key,
auth: secret,
platform: navigator.platform,
userAgent: navigator.userAgent,
screen: {
width: window.screen.width,
height: window.screen.height
}
}
let user = await fetch("/api/me").then(response => response.json())
return fetch("/api/pushsubscriptions/" + user.id + "/add", {
method: "POST",
credentials: "same-origin",
body: JSON.stringify(pushSubscription)
})
})
}
onNotificationClick(evt: NotificationEvent) {
let notification = evt.notification
notification.close()
return (self as any).clients.matchAll().then(function(clientList) {
// If we have a link, use that link to open a new window.
let url = notification.data
if(url) {
return (self as any).clients.openWindow(url)
}
// If there is at least one client, focus it.
if(clientList.length > 0) {
return clientList[0].focus()
}
// Otherwise open a new window
return (self as any).clients.openWindow("https://notify.moe")
})
}
forceClientReloadContent(url: string, eventSource: any) {
let message = {
type: "new content",
url
}
this.postMessageAfterPromise(message, CACHEREFRESH.get(url), eventSource)
}
forceClientReloadPage(url: string, eventSource: any) {
let message = {
type: "reload page",
url
}
this.postMessageAfterPromise(message, RELOADS.get(url.replace("/_/", "/")), eventSource)
}
postMessageAfterPromise(message: any, promise: Promise<any>, eventSource: any) {
if(!promise) {
console.log("forcing reload, cache refresh null")
return eventSource.postMessage(JSON.stringify(message))
}
return promise.then(() => {
console.log("forcing reload after cache refresh")
eventSource.postMessage(JSON.stringify(message))
})
}
installCache() {
// TODO: Implement a solution that caches resources with credentials: "same-origin"
return Promise.resolve()
// return caches.open(this.cache.version).then(cache => {
// return cache.addAll([
// "./",
// "./scripts",
// "https://fonts.gstatic.com/s/ubuntu/v11/4iCs6KVjbNBYlgoKfw7z.ttf"
// ])
// })
}
fromCache(request) {
return caches.open(this.cache.version).then(cache => {
return cache.match(request).then(matching => {
if(matching) {
// console.log("Cache HIT:", request.url)
return Promise.resolve(matching)
}
return Promise.reject("no-match")
})
})
}
}
const serviceWorker = new MyServiceWorker()