This document discusses single-page internet applications (SPI apps) and their implementation using Grails. SPI apps use JavaScript for their model, views, and controllers in the browser, communicating with a REST API on the server. While SPI apps provide faster loading and a better user experience, they require replicating the MVC pattern in JavaScript. Grails 3.0 will support different profiles including REST that simplify the server-side logic. Popular JavaScript frameworks like AngularJS and Ember.js provide similar features to Grails like models, views/templates, and controllers. The TodoMVC site demonstrates these frameworks.

1. Álvaro Sánchez-Mariscal

2. About me
 Passionate software developer.
 Founder & CEO of Salenda and Escuela
de Groovy.
 Groovy/Grails lover since 2007.

3. Typical Grails architecture
 Grails is an MVC, where:
 Model is implemented using POGO’s for
GORM (Hibernate).
 Views are rendered on the server side using
GSP’s and taglibs.
 Controllers are Groovy classes with methods
as actions.

4. So what the hell is
a SPI application?

6. A SPI web app is…
 A web application where you can navigate
without any page refresh.
 REST is used to communicate with the
server.
 The MVC is in the browser, written in
Javascript, where:
 The model are Javascript classes.
 The views are written in HTML.
 The controller, services, etc. are also written in
Javascript.

7. Did you say
Javascript?!?
WTF!
WTF!
Really?!?

8. Some people like Javascript

9. And why the hell
should I care
about SPI?

10. Because it has some advantages
 It’s faster, because:
 Modern browsers have faster Javascript
engines.
 Only the data is sent, not the full markup.
 It has a better user experience,
because:
 Data refreshes instantly.
 It may be easier for the developer:
 If you choose the right framework, you don’t
have to deal with events or callbacks.

11. But, it also has some cons
 What happens if there is no Javascript?
Are you going to gracefully degrade?
 How do we deal with server
communication failures?
 Can I still use the application without an
Internet connection?
 Am I going to replicate the MVC in the
client? Again? In Javascript?

12. Ok. And how do I
implement it using
Grails?

13. Less server logic
 Your Grails application gets simplified.
 Just use GORM (or any other backend)
with a REST API.
 Implementing a REST API with Grails is
really easy.
 Just focus on:
 Transactions.
 Data retrieving and storing.
 Security / authentication.
 Scalability

14. And do I really need
a Grails application
for that?

15. Not really
 You can use Vert.x.
 Or if you want to be really cool, use
Node.js.
 Even if you are really bored, you can
just do it in Java…

16. News from this morning
 In Grails 3.0 you will have application
profiles:
 Servlet “classic” profile.
 Lightweight profile.
 REST profile.

17. Ok with the server
side. What can I
do with the client?

18. There’s lot of frameworks

19. Comprehensive comparision
 Todo MVC, by Addy Osmani
and Sindre Sorhus.
http://addyosmani.github.com/todomvc/

20. Similar features
Models.
}

 Domain classes.
 Views and templates.
 GSP’s and templates.
 {{ }}
 ${}
 Controllers.
 Routing.
 URL Mappings.

21. Gotchas
 Are views on the client really the best
option? What about….?
 i18n?
 Security?
 Caching?
How do we handle dependency
management in our Javascript code?
…

22. Show me some
code please!

23. That’s all!
Thanks!
Álvaro Sánchez-Mariscal
@alvaro_sanchez