Discover Service Worker: a few use cases of this upcoming game changer

1. Discover
ServiceWorker
+SandroPaganotti
@sandropaganotti

2. HTTP GET /cat1.jpg
HTTP Response
SERVER

3. SERVER
serviceworker.js
CACHE
FORGED RESPONSE
OTHER SERVER
SERVICEWORKER
RECEIVES A
FETCH EVENT...

4. SERVER
CACHE
FORGED RESPONSE
OTHER SERVER
serviceworker.js

5. SERVER
CACHE
FORGED RESPONSE
OTHER SERVER
serviceworker.js

6. SERVER
CACHE
FORGED RESPONSE
OTHER SERVER
onfetch = function(evt){
evt.respondWith(
new Response('Sorry no, cats available :)')
);};
serviceworker.js

7. Return
Cached
CACHED?
ONLINE? Forward to
Server
BASIC USAGE:
CACHING FOR
OFFLINE ACCESS
Return
fallback
page

8. importScripts('serviceworker-cache-polyfill.js');
oninstall = function(evt) {
evt.waitUntil(
caches.open('assets').then(function(cache){
return cache.addAll([ 'page.html', 'style.css','app.js','404.html' ]);
})
);
};
onfetch = function(evt) {
evt.respondWith(
caches.match(evt.request).catch(function() {
return evt.default();
}).catch(function() {
return caches.match("404.html");
})
);
};
Not yet available
through polyfill

9. CACHING AND
COMPILING
HANDLEBAR
TEMPLATES
SEARCH/*
*.JPG
Fetch,
Compile,
Cache
CACHED? Return
Cached
Return
Cached
CACHED?
Fetch,
Cache

10. onfetch = function(evt) {
if(//search/[^/]+$/.test(evt.request.url)){
evt.respondWith(caches.match(evt.request).then(function(entry) {
return entry || performSearch(evt.request);
}));
} else if(/.jpg$/.test(evt.request.url)){
evt.respondWith(getImage(evt.request));
}
};
Routing

11. Get Image
getImage = function(request) {
return caches.match(request).then(function(image){
return image || fetch(request.url,
{mode: 'no-cors'}).then(function(res){
return storeResponse('img-cache', request, res);
});
});
};

12. importScripts('handlebars-v2.0.0.js');
var youtube = "https://gdata.youtube.com/feeds/api/videos?alt=json&q=";
performSearch = function(request) {
return caches.match('list.hbs').then(function(tpl) {
return tpl.text();
}).then(function(body){
return fetch(youtube + request.url.split('/').pop()).then(function(res) {
return res.json();
}).then(function(json){
list = list || Handlebars.compile(body);
var response = new Response(list(json),
{ headers: {"Content-Type": "text/html"} });
return storeResponse('pages-cache', request, response);
});})};
Get template from cache
Fetch JSON from YouTube
Generating HTML

13. +SandroPaganotti
@sandropaganotti
Thank you!