Webrocker Blog

'use strict';
(function() {
 
    // Update 'version' if you need to refresh the cache
    const version = '0.1.1';
 
    const staticCache = 'wbr_static';
    const contentCache = 'wbr_content';
    const imgCache = 'wbr_images';
    const assetCache = 'wbr_assets';
    const staticCacheName = version + '_' + staticCache;
    const contentCacheName = version + '_' + contentCache;
    const imgCacheName = version + '_' + imgCache;
    const assetCacheName = version + '_' + assetCache;
 
    // urls that should not be controlled/cached
    const neverCache = [
    	'piwik',
    	'/jaguar/',
  	'/blog/wp-admin/'
    ];
 
    // helper for checking the neverCache array
    var testPos = function(cur,idx,arr){
        // 'this' will be triggered by the 'thisVar' param in array.some(callback,thisVar),
	// i.e. neverCache.some(testPos,request.url)
	if( this.indexOf(cur) !== -1 ){
	    return true;
	}
	return false;
    }
 
    // Store core files in a cache (including a page to display when offline)
    var updateStaticCache = function() {
        return caches.open( staticCacheName )
            .then(function (cache) {
                return cache.addAll([
                    '/blog/wp-content/themes/wbr-theme/style.css',
                    '/blog/wp-content/uploads/2016/04/image-6-530x398.png',
                    '/',
                    '/offline.html'
                ]);
            });
    };
 
    // Put an item in a specified cache
    var stashInCache = function(cacheName, request, response) {
        caches.open(cacheName)
            .then(function (cache) {
                cache.put(request, response);
            });
    };
 
    // Limit the number of items in a specified cache.
    var trimCache = function(cacheName, maxItems) {
        caches.open(cacheName)
            .then(function (cache) {
                cache.keys()
                    .then(function (keys) {
                        if (keys.length > maxItems) {
                            cache.delete(keys[0])
                                .then(trimCache(cacheName, maxItems));
                        }
                    });
            });
    };
 
    // Remove caches whose name is no longer valid
    var clearOldCaches = function() {
    	return caches.keys()
            .then(function (keys) {
                return Promise.all(keys
                    .filter(function (key) {
                      return key.indexOf(version) !== 0;
                    })
                    .map(function (key) {
                      return caches.delete(key);
                    })
                );
            })
    }
 
    self.addEventListener('install', function (event) {
        event.waitUntil(updateStaticCache()
            .then(function () {
                return self.skipWaiting();
            })
        );
    });
 
    self.addEventListener('activate', function (event) {
        event.waitUntil(clearOldCaches()
            .then(function () {
                return self.clients.claim();
            })
        );
    });
 
    self.addEventListener('message', function(event) {
    	if (event.data.command == 'trimCaches') {
    		trimCache(contentCacheName, 25);
    		trimCache(imgCacheName, 45);
    		trimCache(assetCacheName, 35);
    	}
    });
 
    self.addEventListener('activate', function (event) {
        event.waitUntil(
            caches.keys()
                .then(function (keys) {
                    // Remove caches whose name is no longer valid
                    return Promise.all(keys
                        .filter(function (key) {
                          //console.log(key);
                          //console.log(key.indexOf(version) !== 0);
                          return key.indexOf(version) !== 0;
                        })
                        .map(function (key) {
                          return caches.delete(key);
                        })
                    );
                })
        );
    });
 
    self.addEventListener('fetch', function (event) {
 
        var request = event.request;
 
        // if is request for cms admin, do nothing.
        if( neverCache.some(testPos,request.url)){
        	return
        }
 
        // Always fetch non-GET requests from the network
        if (request.method !== 'GET') {
            event.respondWith(
                fetch(request)
                    .catch(function () {
                        return caches.match('/offline.html');
                    })
            );
            return;
        }
 
        // For HTML requests, try the network first, fall back to the cache, finally the offline page
        if (request.headers.get('Accept').indexOf('text/html') !== -1) {
            // Fix for Chrome bug: https://code.google.com/p/chromium/issues/detail?id=573937
            if (request.mode != 'navigate') {
                request = new Request(request.url, {
                    method: 'GET',
                    headers: request.headers,
                    mode: request.mode,
                    credentials: request.credentials,
                    redirect: request.redirect
                });
            }
            event.respondWith(
                fetch(request)
                    .then(function (response) {
                        // Stash a copy of this page in the cache
                        var copy = response.clone();
                        stashInCache(contentCacheName, request, copy);
                        return response;
                    })
                    .catch(function () {
                        return caches.match(request)
                            .then(function (response) {
                                return response || caches.match('/offline.html');
                            })
                    })
            );
            return;
        }
 
        // For non-HTML requests,
        // - look in the cache first,
        // - fall back to the network, cache it,
        // - else show offline img if is image request
        event.respondWith(
            caches.match(request)
                .then(function (response) {
                    return response || fetch(request)
                    	// update asset | image cache
                    	.then(function (response) {
                        	// Stash a copy of this page in the cache.
                        	var copy = response.clone();
                        	var myCache = assetCacheName;
                        	if (request.headers.get('Accept').indexOf('image') !== -1) {
                        		myCache = imgCacheName;
                        	}
                        	stashInCache(myCache, request, copy);
                        	return response;
                    	})
                        .catch(function () {
                            // If the request is for an image, show an offline placeholder
                            if (request.headers.get('Accept').indexOf('image') !== -1) {
                                return new Response('Offlineoffline', { headers: { 'Content-Type': 'image/svg+xml' }});
                            }
                        });
                })
        );
    });
})();