Included the default serviceworker, updated the manifest, Add the default offline page, updated the unit test, Redme

README.md

@@ -60,11 +60,11 @@ All settings are optional, and the app will work fine with its internal defaults
 
 Add the progressive web app URLs to urls.py:
 ```python
-from django.conf.urls import url, include
+from django.urls import path, include
 
 urlpatterns = [
     ...
-    url('', include('pwa.urls')),  # You MUST use an empty string as the URL prefix
+    path('', include('pwa.urls')),  # You MUST use an empty string as the URL prefix
     ...
 ]
 ```
@@ -86,18 +86,85 @@ While running the Django test server:
 
 1. Verify that `/manifest.json` is being served
 1. Verify that `/serviceworker.js` is being served
+1. Verify that `/offline` is being served
 1. Use the Application tab in the Chrome Developer Tools to verify the progressive web app is configured correctly.
 1. Use the "Add to homescreen" link on the Application Tab to verify you can add the app successfully.
 
+
+The Service Worker
+=====
+By default, the service worker implemented by this app is:
+```js
+// Base Service Worker implementation.  To use your own Service Worker, set the PWA_SERVICE_WORKER_PATH variable in settings.py
+
+var staticCacheName = "django-pwa-v" + new Date().getTime();
+var filesToCache = [
+    '/offline',
+    '/css/django-pwa-app.css',
+    '/images/icons/icon-72x72.png',
+    '/images/icons/icon-96x96.png',
+    '/images/icons/icon-128x128.png',
+    '/images/icons/icon-144x144.png',
+    '/images/icons/icon-152x152.png',
+    '/images/icons/icon-192x192.png',
+    '/images/icons/icon-384x384.png',
+    '/images/icons/icon-512x512.png',
+];
+
+// Cache on install
+self.addEventListener("install", event => {
+    this.skipWaiting();
+    event.waitUntil(
+        caches.open(staticCacheName)
+            .then(cache => {
+                return cache.addAll(filesToCache);
+            })
+    )
+});
+
+// Clear cache on activate
+self.addEventListener('activate', event => {
+    event.waitUntil(
+        caches.keys().then(cacheNames => {
+            return Promise.all(
+                cacheNames
+                    .filter(cacheName => (cacheName.startsWith("django-pwa-")))
+                    .filter(cacheName => (cacheName !== staticCacheName))
+                    .map(cacheName => caches.delete(cacheName))
+            );
+        })
+    );
+});
+
+// Serve from Cache
+self.addEventListener("fetch", event => {
+    event.respondWith(
+        caches.match(event.request)
+            .then(response => {
+                return response || fetch(event.request);
+            })
+            .catch(() => {
+                return caches.match('offline');
+            })
+    )
+});
+```
+
 Adding Your Own Service Worker
 =====
-By default, the service worker implemented by this app is empty.  To add service worker functionality, you'll want to create a `serviceworker.js` or similarly named file, and then point at it using the PWA_SERVICE_WORKER_PATH variable.
+By default, the service worker implemented by this app is empty.  To add service worker functionality, you'll want to create a `serviceworker.js` or similarly named template in a template directory, and then point at it using the PWA_SERVICE_WORKER_PATH variable (PWA_APP_FETCH_URL is passed through).
 
 ```python
-PWA_SERVICE_WORKER_PATH = os.path.join(BASE_DIR, 'my_app', 'serviceworker.js')
+PWA_SERVICE_WORKER_PATH = 'my_app/serviceworker.js'
 
 ```
 
+The offline view
+=====
+By default, the offline view is implemented in `templates/offline.html`
+You can overwrite it in a template directory if you continue using the default `serviceworker.js`.  
+
+
 Feedback
 =====
 I welcome your feedback and pull requests.  Enjoy!