rough first functional implementation of fetching config via plugins (ref. #30)

service-worker.js

@@ -155,6 +155,8 @@ let getConfigJSON = async (cresponse) => {
         self.log('service-worker', `config.json response status is not 200: ${cdata.status} ${cdata.statusText})`)
         return false;
     }
+    // cloning the response before applying json()
+    // so that we can cache the response later
     var cdata = await cresponse.clone().json()
     if (verifyConfigData(cdata)) {
         return cdata;
@@ -177,6 +179,9 @@ let initServiceWorker = async () => {
     // so that we get an informative message if there's an error
     try {
 
+        // we'll need this later
+        var cresponse = null
+        
         // get the config
         // 
         // self.registration.scope contains the scope this service worker is registered for
@@ -187,26 +192,24 @@ let initServiceWorker = async () => {
             var configURL = self.registration.scope + "config.json"
             
             // get the config data from cache
-            var cresponse = await caches.match(configURL)
+            cresponse = await caches.match(configURL)
             var cdata = await getConfigJSON(cresponse)
             
             // did it work?
             if (cdata != false) {
                 // we need to know if the config was already cached
                 self.log('service-worker', `valid config file retrieved from cache.`)
-                var wasCached = true
                 
             // cache failed to deliver
             } else {
                 
                 // try fetching directly from the main domain
+                self.log('service-worker', `config file not found in cache, fetching.`)
                 var cresponse = await fetch(configURL)
                 cdata = await getConfigJSON(cresponse)
                 
                 // did that work?
                 if (cdata != false) {
-                    self.log('service-worker', `config file not found in cache, fetching.`)
-                    var wasCached = false
                     // cache it, asynchronously
                     cacheConfigJSON(configURL, cresponse)
                 
@@ -320,8 +323,29 @@ let initServiceWorker = async () => {
         }
         
         // inform
-        self.log('service-worker', `DEBUG: Strategy in use: ${self.LibResilientPlugins.map(p=>p.name).join(', ')}`)
+        self.log('service-worker', `service worker initialized.\nstrategy in use: ${self.LibResilientPlugins.map(p=>p.name).join(', ')}`)
         initDone = true;
+        
+        // regardless how we got the config file, if it's older than 24h...
+        if ( (new Date()) - Date.parse(cresponse.headers.get('date')) > 86400000) {
+            
+            // try to get it asynchronously through the plugins, and cache it
+            self.log('service-worker', `config.json stale, fetching through plugins`)
+            
+            getResourceThroughLibResilient(configURL, {}, 'libresilient-internal', false, false)
+                .then(async cresponse=>{
+                    
+                    // extract JSON and verify it
+                    var cdata = await getConfigJSON(cresponse)
+                
+                    // did that work?
+                    if (cdata != false) {
+                        self.log('service-worker', `config.json successfully fetched through plugins; caching.`)
+                        // cache it, asynchronously
+                        cacheConfigJSON(configURL, cresponse)
+                    }
+                })
+        }
 
     } catch(e) {
         // we only get a cryptic "Error while registering a service worker"