Service worker

src/Controllers/ServiceWorkerController.php

@@ -3,6 +3,11 @@
 namespace MichelSteege\ProgressiveWebApp\Controllers;
 
 use SilverStripe\Control\Controller;
+use SilverStripe\Control\Director;
+use SilverStripe\ORM\ArrayList;
+use SilverStripe\View\ArrayData;
+use SilverStripe\Core\ClassInfo;
+use MichelSteege\ProgressiveWebApp\Interfaces\ServiceWorkerCacheProvider;
 
 class ServiceWorkerController extends Controller {
 
@@ -12,6 +17,11 @@ class ServiceWorkerController extends Controller {
     private static $allowed_actions = [
         'index'
     ];
+    
+    /**
+     * @config
+     */
+    private static $debug_mode = true;
 
     /**
      * Default controller action for the service-worker.js file
@@ -22,5 +32,44 @@ class ServiceWorkerController extends Controller {
         $this->getResponse()->addHeader('Content-Type', 'application/javascript; charset="utf-8"');
         return $this->renderWith('ServiceWorker');
     }
+    
+    /**
+     * Base URL
+     * @return varchar
+     */
+    public function BaseUrl() {
+        return Director::baseURL();
+    }
+    
+    /**
+     * Debug mode
+     * @return bool
+     */
+    public function DebugMode() {
+        if(Director::isDev()){
+            return true;
+        }
+        return $this->config()->get('debug_mode');
+    }
+    
+    /**
+     * A list with file to cache in the install event
+     * @return ArrayList
+     */
+    public function CacheOnInstall() {
+        $paths = [];
+        foreach(ClassInfo::implementorsOf(ServiceWorkerCacheProvider::class) as $class){
+            foreach($class::getServiceWorkerCachedPaths() as $path){
+                $paths[] = $path;
+            }
+        }
+        $list = new ArrayList();
+        foreach($paths as $path){
+            $list->push(new ArrayData([
+                'Path' => $path
+            ]));
+        }
+        return $list;
+    }
 
 }

src/Interfaces/ServiceWorkerCacheProvider.php

@@ -0,0 +1,9 @@
+<?php
+
+namespace MichelSteege\ProgressiveWebApp\Interfaces;
+
+interface ServiceWorkerCacheProvider {
+    
+    public static function getServiceWorkerCachedPaths();
+    
+}

templates/ServiceWorker.ss

@@ -1,26 +1,121 @@
-self.addEventListener('install', function(e) {
-    console.log('Install');
-    /*
- e.waitUntil(
-   caches.open('airhorner').then(function(cache) {
-     return cache.addAll([
-       '/',
-       '/index.html',
-       '/index.html?homescreen=1',
-       '/?homescreen=1',
-       '/styles/main.css',
-       '/scripts/main.min.js',
-       '/sounds/airhorn.mp3'
-     ]);
-   })
- );
- */
-});
+<%--<script>//Ugly fix for code highlights--%>
+    var version = 'v1::';
+    var debug = <% if $DebugMode %>true<% else %>false<% end_if %>;
+    
+    /**
+     * Console.log proxy for quick enabling/disabling
+     */
+    function log(msg){
+        if(debug){
+            console.log(msg);
+        }
+    }
 
-self.addEventListener('fetch', function(event) {
- console.log(event.request.url);
-});
+    /**
+     * Service worker installation
+     */
+    self.addEventListener('install', function (event) {
+        log('Service worker: install start');
+        event.waitUntil(caches.open(version + 'fundamentals').then(function (cache) {
+            //Install all required pages/assets
+            return cache.addAll([
+                '$BaseUrl'<% if $CacheOnInstall %>,<% end_if %>
+                <% if $CacheOnInstall %>
+                    <% loop $CacheOnInstall %>
+                        '$Path'<% if not $Last %>,<% end_if %>
+                    <% end_loop %>
+                <% end_if %>
+            ]);
+        }).then(function () {
+            log('Service worker: install completed');
+        }).catch(function(){
+            log('Service worker: install failed');
+        }));
+    });
 
-self.addEventListener('beforeinstallprompt', function(event) {
- console.log('beforeinstallprompt');
-});
+    /**
+     * Service worker activation
+     */
+    self.addEventListener('activate', function (event) {
+        log('Service worker: activate start');
+        event.waitUntil(caches.keys().then(function (keys) {
+            //Remove old cache entries
+            return Promise.all(keys.filter(function (key) {
+                return !key.startsWith(version);
+            }).map(function (key) {
+                return caches.delete(key);
+            }));
+        }).then(function () {
+            log('Service worker: activate completed');
+        }));
+    });
+
+    /**
+     * Fetch handler
+     */
+    self.addEventListener('fetch', function (event) {
+        //We are only interested in get requests
+        if (event.request.method !== 'GET') {
+            return;
+        }
+        
+        //Parse the url
+        var requestURL = new URL(event.request.url);
+        
+        //Test for images
+        if (/\.(jpg|jpeg|png|gif|webp)$/.test(requestURL.pathname)) {
+            log('Service worker: skip image ' + event.request.url);
+            //For now we skip images but change this later to maybe some caching and/or an offline fallback
+            return;
+        }
+        
+        //Check for our own urls
+        if (requestURL.origin == location.origin) {
+            //All our own urls are following this route:
+            //-If there is cache serve from cache but also update the cache from the network
+            //-If there is no cache then get from the network and put in the cache
+            //-If both fail fallback to a generic offline message
+            event.respondWith(caches.match(event.request).then(function (cached) {
+                var networked = fetch(event.request).then(fetchedFromNetwork, unableToResolve).catch(unableToResolve);
+                log('Service worker: fetch event ' + (cached ? '(cached)' : '(network)') + ' - ' + event.request.url);
+                return cached || networked;
+                
+                /**
+                * Fetched from network handler
+                */
+               function fetchedFromNetwork(response) {
+                   var cacheCopy = response.clone();
+                   log('Service worker fetch from network - ' + event.request.url);
+                   caches.open(version + 'pages').then(function add(cache) {
+                       cache.put(event.request, cacheCopy);
+                   }).then(function () {
+                       log('Service worker: fetch response stored in cache - ' + event.request.url);
+                   });
+                   return response;
+               }
+
+               /**
+                * No internet and no cache handler
+                */
+               function unableToResolve(error) {
+                   log('Service worker: fetch request failed in both cache and network ' + error);
+                   return new Response('<h1>Service Unavailable</h1>', {
+                       status: 503,
+                       statusText: 'Service Unavailable',
+                       headers: new Headers({
+                           'Content-Type': 'text/html'
+                       })
+                   });
+               }
+                
+            }));
+            return;
+        }
+        
+        //All others, nothing special here
+        log('Service worker: other url - ' + event.request.url);
+        event.respondWith(caches.match(event.request).then(function(response) {
+            return response || fetch(event.request);
+        }));
+    });
+    //<%--Ugly fix for code highlights</script>--%>