Fix service worker cache, handle refresh better

sw.js

@@ -1,129 +1,221 @@
-const VERSION = 'v14'
+const VERSION = 'v15'
 const API_ORIGIN = 'https://scraper.infotren.dcdev.ro/'
 const API_TRAINS = `${API_ORIGIN}v3/trains`
 const API_STATIONS = `${API_ORIGIN}v3/stations`
 
-self.addEventListener('install', (event) => {
-  event.waitUntil(
-    caches
-      .open(VERSION)
-      .then((cache) =>
-        cache.addAll([
-          // Root
-          '/',
+const CACHE_FIRST = [
+	// Root
+	'/',
+
+	// Utility JS
+	'/common/worker.js',
+	'/common/items.js',
+	'/common/back.js',
+	'/common/tabs.js',
 
-          // Utility JS
-          '/common/worker.js',
-          '/common/items.js',
-          '/common/back.js',
-          '/common/tabs.js',
+	// Base
+	'/base.css',
 
-          // Base
-          '/base.css',
+	// Pages
+	'/index.html',
 
-          // Pages
-          '/index.html',
+	'/about.html',
 
-          '/about.html',
+	'/train.html',
+	'/train.js',
 
-          '/train.html',
-          '/train.js',
+	'/view-train.html',
+	'/view-train.js',
+	'/view-train.css',
 
-          '/view-train.html',
-          '/view-train.js',
-          '/view-train.css',
+	'/station.html',
+	'/station.js',
 
-          '/station.html',
-          '/station.js',
+	'/view-station.html',
+	'/view-station.js',
+	'/view-station.css',
 
-          '/view-station.html',
-          '/view-station.js',
-          '/view-station.css',
+	// API
+	API_TRAINS,
+	API_STATIONS,
+];
 
-          // API
-          API_TRAINS,
-          API_STATIONS,
+/**
+ * @param {string} url
+ * @returns {boolean}
+ */
+function shouldReturnFromCacheFirst(url) {
+	return CACHE_FIRST.map(u => u.includes('://') ? u : self.location.origin + u).includes(url.split('?')[0])
+}
 
-        ])
-      )
-  )
+self.addEventListener('install', (event) => {
+	event.waitUntil(
+		caches
+			.open(VERSION)
+			.then((cache) =>
+				cache.addAll(CACHE_FIRST)
+			)
+	)
 })
 
 const deleteCache = (/** @type {string} */ key) => caches.delete(key)
 
 const deleteOldCaches = async () => {
-   const cacheKeepList = [VERSION]
-   const keyList = await caches.keys()
-   const cachesToDelete = keyList.filter((key) => !cacheKeepList.includes(key))
-   await Promise.all(cachesToDelete.map(deleteCache))
+	const cacheKeepList = [VERSION]
+	const keyList = await caches.keys()
+	const cachesToDelete = keyList.filter((key) => !cacheKeepList.includes(key))
+	await Promise.all(cachesToDelete.map(deleteCache))
 }
 
 // Enable navigation preload
 const enableNavigationPreload = async () => {
-  if (self.registration.navigationPreload) {
-    // Enable navigation preloads!
-    await self.registration.navigationPreload.enable()
-  }
+	if (self.registration.navigationPreload) {
+		// Enable navigation preloads!
+		await self.registration.navigationPreload.enable()
+	}
 }
 
 self.addEventListener('activate', (event) => {
-  event.waitUntil(Promise.all([deleteOldCaches(), enableNavigationPreload()]))
+	event.waitUntil(Promise.all([deleteOldCaches(), enableNavigationPreload()]))
 })
 
+/**
+ * @param {RequestInfo | URL} request
+ * @param {Response} response
+ * @returns {Promise<void>}
+ */
 const putInCache = async (request, response) => {
-  const cache = await caches.open(VERSION)
-  await cache.put(request, response)
+	const cache = await caches.open(VERSION)
+	// try {
+	// 	response.headers.set('SW-Cached-At', new Date().toISOString())
+	// }
+	// catch {
+		const headers = new Headers(response.headers)
+		headers.set('SW-Cached-At', new Date().toISOString())
+		response = new Response(response.body, {
+			status: response.status,
+			statusText: response.statusText,
+			headers,
+		})
+	// }
+	await cache.put(request, response)
 }
 
 const cacheFirst = async ({ request, preloadResponsePromise, refreshAnyway }) => {
-  // First try to get the resource from the cache
-  const responseFromCache = await caches.match(request)
-  if (responseFromCache) {
-    if (refreshAnyway) {
-      console.log('request in cache, refreshing anyway but returning cache', request);
-      ((async () => {
-        try {
-          const response = await fetch(request)
-          if (response.ok) {
-            putInCache(request, response)
-          }
-        }
-        catch {}
-      })())
-    }
-    return responseFromCache
-  }
-
-  // Next try to use (and cache) the preloaded response, if it's there
-  if (preloadResponsePromise) {
-    const preloadResponse = await preloadResponsePromise
-    if (preloadResponse && preloadResponse.ok) {
-      console.info('using preload response', preloadResponse)
-      putInCache(request, preloadResponse.clone())
-      return preloadResponse
-    }
-    else {
-      console.log('got not ok preloadResponse, ignoring', preloadResponse)
-    }
-  }
-
-  // Next try to get the resource from the network
-  const responseFromNetwork = await fetch(request)
-  // response may be used only once
-  // we need to save clone to put one copy in cache
-  // and serve second one
-  if (responseFromNetwork.ok) {
-    putInCache(request, responseFromNetwork.clone())
-  }
-  return responseFromNetwork;
+	// First try to get the resource from the cache
+	const responseFromCache = await caches.match(request)
+	if (responseFromCache) {
+		if (refreshAnyway) {
+			console.log('[cf] using cache response; refreshing anyway but returning cache', responseFromCache);
+			((async () => {
+				try {
+					const response = await fetch(request)
+					if (response.ok) {
+						await putInCache(request, response)
+					}
+				}
+				catch {}
+			})())
+		}
+		else {
+			console.log('[cf] using cache response', responseFromCache)
+		}
+		return responseFromCache
+	}
+
+	// Next try to use (and cache) the preloaded response, if it's there
+	if (preloadResponsePromise) {
+		const preloadResponse = await preloadResponsePromise
+		if (preloadResponse && preloadResponse.ok) {
+			console.info('[cf] using preload response', preloadResponse)
+			await putInCache(request, preloadResponse.clone())
+			return preloadResponse
+		}
+		else {
+			console.log('[cf] got not ok preloadResponse, ignoring', preloadResponse)
+		}
+	}
+
+	// Next try to get the resource from the network
+	const responseFromNetwork = await fetch(request)
+	// response may be used only once
+	// we need to save clone to put one copy in cache
+	// and serve second one
+	if (responseFromNetwork.ok) {
+		console.log('[cf] using network response; ok so also cache', responseFromNetwork)
+		await putInCache(request, responseFromNetwork.clone())
+	}
+	else {
+		console.log('[cf] using network not ok response', responseFromNetwork)
+	}
+	return responseFromNetwork;
+}
+
+const networkFirst = async ({ request, preloadResponsePromise }) => {
+	// First try to use (and cache) the preloaded response, if it's there
+	if (preloadResponsePromise) {
+		const preloadResponse = await preloadResponsePromise
+		if (preloadResponse && preloadResponse.ok) {
+			console.info('[nf] using preload response', preloadResponse)
+			await putInCache(request, preloadResponse.clone())
+			return preloadResponse
+		}
+		else {
+			console.log('[nf] got not ok preloadResponse, ignoring', preloadResponse)
+		}
+	}
+
+	// Next try to get the resource from the network
+	let responseFromNetwork
+	let errorFromNetwork
+	try {
+		responseFromNetwork = await fetch(request)
+	}
+	catch (e) {
+		responseFromNetwork = null
+		errorFromNetwork = e
+	}
+	// If the response is ok, put it in cache and respond
+	if (responseFromNetwork && responseFromNetwork.ok) {
+		console.log('[nf] using ok network response', responseFromNetwork)
+		await putInCache(request, responseFromNetwork.clone())
+		return responseFromNetwork
+	}
+
+	// Response from network wasn't ok, try to find in cache
+	const responseFromCache = await caches.match(request)
+	if (responseFromCache) {
+		console.log('[nf] using cache response', responseFromCache)
+		return responseFromCache
+	}
+
+	// If we didn't find a cached response, return the fresh network error
+	if (responseFromNetwork) {
+		console.log('[nf] using network not ok response', responseFromNetwork)
+		return responseFromNetwork
+	}
+	else {
+		console.log('[nf] throwing network error', errorFromNetwork)
+		throw errorFromNetwork
+	}
 }
 
 self.addEventListener('fetch', (event) => {
-  event.respondWith(
-    cacheFirst({
-      request: event.request,
-      preloadResponsePromise: event.preloadResponse,
-      refreshAnyway: [API_STATIONS, API_TRAINS].includes(event.request.url.split('?')[0]),
-    })
-  )
+	if (shouldReturnFromCacheFirst(event.request.url)) {
+		event.respondWith(
+			cacheFirst({
+				request: event.request,
+				preloadResponsePromise: event.preloadResponse,
+				refreshAnyway: [API_STATIONS, API_TRAINS].includes(event.request.url.split('?')[0]),
+			})
+		)
+	}
+	else {
+		event.respondWith(
+			networkFirst({
+				request: event.request,
+				preloadResponsePromise: event.preloadResponse,
+			})
+		)
+	}
 })

view-train.js

@@ -1,4 +1,10 @@
+/**
+ * @type {string}
+ */
 var trainNumber
+/**
+ * @type {Date}
+ */
 var date
 var groupIndex = null
 
@@ -6,6 +12,9 @@ var yesterday = false
 var showKm = false
 
 var trainData = null
+/**
+ * @type {?Date}
+ */
 var lastSuccessfulFetch = null
 
 /**
@@ -55,8 +64,9 @@ var lastSuccessfulFetch = null
 
 /**
  * @param {{ rank: string; number: string; operator: string; date: string; groups: Group[]; }} data
+ * @param {?Date} fetchDate
  */
-function onTrainData(data) {
+function onTrainData(data, fetchDate) {
 	var title = document.getElementById('title')
 	title.textContent = ''
 	title.appendChild(document.createTextNode('Train '))
@@ -384,10 +394,14 @@ function onTrainData(data) {
 		}
 	})
 
-	lastSuccessfulFetch = new Date()
+	lastSuccessfulFetch = fetchDate || new Date()
 }
 
 var refreshStopToken = null
+
+/**
+ * @returns {Promise<boolean>}
+ */
 function refresh() {
 	function reschedule(timeout) {
 		if (refreshStopToken != null) {
@@ -415,14 +429,25 @@ function refresh() {
 			reschedule(10000)
 			return
 		}
-		return response.json()
+		var cacheDate = response.headers.get('SW-Cached-At')
+		return response.json().then(function (data) {
+			data['$cacheDate'] = cacheDate
+			return data
+		})
 	}).then(function (response) {
 		if (!response) {
 			return
 		}
+		var cacheDate = response['$cacheDate']
+		if (cacheDate) {
+			cacheDate = new Date(cacheDate)
+		}
+		var success = !cacheDate
 		trainData = response
-		onTrainData(response)
-		reschedule()
+		onTrainData(response, cacheDate)
+		// Check in 1 seconds if network error
+		reschedule(success ? undefined : 1000)
+		return success
 	}).catch(function (e) {
 		// Check in 1 second if network error
 		reschedule(1000)
@@ -437,7 +462,24 @@ window.addEventListener('unload', function (e) {
 })
 
 function rsk() {
-	refresh()
+	function changeRskText(newText) {
+		document.querySelectorAll('.rsk').forEach(function (elem) {
+			elem.textContent = newText
+		})
+	}
+
+	changeRskText('Refreshing...')
+	refresh().catch(function () { return false}).then(function (success) {
+		if (!success) {
+			changeRskText('Refreshing failed')
+			setTimeout(function (_) {
+				changeRskText('Refresh')
+			}, 3000)
+		}
+		else {
+			changeRskText('Refresh')
+		}
+	})
 }
 
 window.addEventListener('popstate', function (e) {