From 01243ba4c111f95611c3814b07fb7a7906fad354 Mon Sep 17 00:00:00 2001
From: Nolan Lawson <nolan@nolanlawson.com>
Date: Sun, 14 Jan 2018 17:13:42 -0800
Subject: [PATCH] more work on service worker

---
 routes/_utils/asyncModules.js | 14 +++++++
 templates/main.js             | 21 ++++++----
 templates/service-worker.js   | 77 ++++++++++++++++++++++++++---------
 3 files changed, 84 insertions(+), 28 deletions(-)
 create mode 100644 routes/_utils/asyncModules.js

diff --git a/routes/_utils/asyncModules.js b/routes/_utils/asyncModules.js
new file mode 100644
index 00000000..562bf34d
--- /dev/null
+++ b/routes/_utils/asyncModules.js
@@ -0,0 +1,14 @@
+const importURLSearchParams = () => import(
+  /* webpackChunkName: 'url-search-params' */ 'url-search-params'
+  ).then(Params => {
+  window.URLSearchParams = Params
+  Object.defineProperty(window.URL.prototype, 'searchParams', {
+    get() {
+      return new Params(this.search)
+    }
+  })
+})
+
+export {
+  importURLSearchParams
+}
\ No newline at end of file
diff --git a/templates/main.js b/templates/main.js
index d044b236..2f3817d6 100644
--- a/templates/main.js
+++ b/templates/main.js
@@ -1,16 +1,19 @@
-import { init } from 'sapper/runtime.js';
+import { init } from 'sapper/runtime.js'
+import toast from '../routes/_utils/toast.js'
 
 // polyfills
 Promise.all([
-  typeof URLSearchParams === 'undefined' && import(/* webpackChunkName: 'url-search-params' */ 'url-search-params').then(Params => {
-    window.URLSearchParams = Params
-    Object.defineProperty(window.URL.prototype, 'searchParams', {
-      get() {
-        return new Params(this.search)
-      }
-    })
-  })
+  typeof URLSearchParams === 'undefined' && importURLParams()
 ]).then(() => {
   // `routes` is an array of route objects injected by Sapper
   init(document.querySelector('#sapper'), __routes__)
+
+  if (navigator.serviceWorker && navigator.serviceWorker.controller) {
+    navigator.serviceWorker.controller.onstatechange = (e) => {
+      if (e.target.state === 'redundant') {
+        toast.say('App update available. Reload to update.');
+      }
+    }
+  }
+
 })
\ No newline at end of file
diff --git a/templates/service-worker.js b/templates/service-worker.js
index dcffa322..27ddf996 100644
--- a/templates/service-worker.js
+++ b/templates/service-worker.js
@@ -36,8 +36,18 @@ self.addEventListener('activate', event => {
   )
 })
 
+const NETWORK_ONLY = [
+  '/oauth'
+]
+
+const CACHE_FIRST = [
+  '/api/v1/accounts/verify_credentials',
+  '/system/accounts/avatars'
+]
+
 self.addEventListener('fetch', event => {
-  const url = new URL(event.request.url)
+  const req = event.request
+  const url = new URL(req.url)
 
   // don't try to handle e.g. data: URIs
   if (!url.protocol.startsWith('http')) {
@@ -46,7 +56,7 @@ self.addEventListener('fetch', event => {
 
   // always serve assets and webpack-generated files from cache
   if (cached.has(url.pathname)) {
-    event.respondWith(caches.match(event.request))
+    event.respondWith(caches.match(req))
     return
   }
 
@@ -55,30 +65,59 @@ self.addEventListener('fetch', event => {
   // app, but if it's right for yours then uncomment this section
 
   if (url.origin === self.origin && routes.find(route => route.pattern.test(url.pathname))) {
-    event.respondWith(caches.match('/index.html'));
-    return;
+    event.respondWith(caches.match('/index.html'))
+    return
+  }
+
+  // Non-GET and for certain endpoints (e.g. OAuth), go network-only
+  if (req.method !== 'GET' ||
+      NETWORK_ONLY.some(pattern => url.pathname.startsWith(pattern))) {
+    console.log('Using network-only for', url.href)
+    event.respondWith(fetch(req))
+    return
+  }
+
+  // For these, go cache-first.
+  if (CACHE_FIRST.some(pattern => url.pathname.startsWith(pattern))) {
+    console.log('Using cache-first for', url.href)
+    event.respondWith(caches
+      .open(`offline${timestamp}`)
+      .then(async cache => {
+        let response = await cache.match(req)
+        if (response) {
+          // update asynchronously
+          fetch(req).then(response => {
+            cache.put(req, response.clone())
+          })
+          return response
+        }
+        response = await fetch(req)
+        cache.put(req, response.clone())
+        return response
+      }))
+    return
   }
 
 
   // for everything else, try the network first, falling back to
   // cache if the user is offline. (If the pages never change, you
   // might prefer a cache-first approach to a network-first one.)
-  event.respondWith(
-    caches
-      .open(`offline${timestamp}`)
-      .then(async cache => {
-        try {
-          const response = await fetch(event.request)
-          cache.put(event.request, response.clone())
+  event.respondWith(caches
+    .open(`offline${timestamp}`)
+    .then(async cache => {
+      try {
+        console.log('Using network-first for', url.href)
+        const response = await fetch(req)
+        cache.put(req, response.clone())
+        return response
+      } catch (err) {
+        const response = await cache.match(req)
+        if (response) {
           return response
-        } catch (err) {
-          const response = await cache.match(event.request)
-          if (response) {
-            return response
-          }
-
-          throw err
         }
-      })
+
+        throw err
+      }
+    })
   )
 })