Meteoroid

1. Meteoroid Towards a real MVC for the Web Lautaro Fernández Santiago Robles Andrés Fortier Stephane Ducasse Gustavo Rossi Silvia Gordillo (lfernandez@lifia.info.unlp.edu.ar) (srobles@lifia.info.unlp.edu.ar) (andres@lifia.info.unlp.edu.ar) (stephane.ducasse@inria.fr) (gustavo@lifia.info.unlp.edu.ar) (gordillo@lifia.info.unlp.edu.ar)

2. Web: To Infinity And Beyond! • Cheaper & Faster • Lots of services are provided via Web • Mail • Home banking • Collaborative editors • Social networks • E-Commerce • Etc. • Present on any device

3. For the last one a new approach is needed Web evolution Beginning • Request/response • Static information Now the Web is more complex, requiring • Complex models • Dynamic information • More interaction client/server • Client’s updates from the server without the request

4. Request/Response mechanism Comet mechanism Comet • A way to push data from the server into Web browsers • Umbrella of technologies • JavaScript • Ajax • Streaming • Browser-dependent hack

5. Comet (cont.) • Not an standard (yet) • Common technique for all browsers • Waiting cursor issues • Throbber issues • Status bar issues • Best techniques for browsers

6. Understanding some background

7. Seaside • Framework to build Web applications • Characteristics: • Nesting components • Hot debugging and recompilation • Multiple control flow • Stack reification for call and answer • Action callbacks • Etc.

8. Model-View-Controller • Model • Independent from Views • View • Displays Model information • Controller • Processes events

9. Announcements • It is an observer framework simpler and more powerful than legacy frameworks • Triggers robust objects instead of symbols, which make the concrete observer behaviour much easier Vs. self change: #value with: aValue self announce: (ValueAnnouncement with: aValue)

10. Value Models • General idea • Holds a model • Understands #value and #value: • Notifies its dependents when its value changes • Simple, standard • Useful for widgets • Widgets access the value independently of the model • Uniform way to access the value

11. Meteoroid • Framework to create Live Web applications • Combines • Comet concept • Seaside features • Announcements • MVC pattern • Value Models

12. Meteoroid Layers • Meteoroid is divided in different layers • Every layer provides • More functionality • More abstraction

13. JavaScript Layer • Bottom Layer, less abstraction • Provides • A Comet connection • Message #pushScript: aScript • DOM manipulation self pushScript: 'alert(“Hello World”);'

14. Demo

15. Announcement Layer  More abstraction • Through MVC this layer will handle the dependencies • Add & remove View-Model dependencies automatically • Messages to update and insert JavaScript automatically MeteoroidComponent>>initialize self on: ValueChangedAnnouncement         of: self model         update: 'someDOM_ID'         callback: [:html :announcement :announcer| html text: announcer value         ]

16. Demo

17. Web Value Model Layer • Combines • Announcement layer • HTML widgets • Value Models  • Allows to create Web apps like Desktop apps

18. Web Value Model Layer (cont.) • WebValueModel • ValueModel Wrapper • Allows to use #change: and #announce: • Updateables Widgets • Access a Value Model • Value Model notifies a WebValueModel which updates the web widget 

19. Demo

20. Demo

21. That’s all, Thanks!