The document discusses developing a simple multi-user application using HTML5 WebSockets without plugins. It provides an example of a simple Pong game and references the WebSocket specification and Java implementation using HTTPServlet and interfaces. The target is to understand how "web" applications can be interactive without plugins or applets.

1. Alberto Mancini
alberto@jooink.com
Francesca Tosi
francesca@jooink.com
6 Luglio 2011- Palazzo Corsini - Firenze

2. Target
http://www.jooink.com
Cercare di capire quanto le applicazioni
"web" possono essere interattive
... senza flash
... senza applets
... senza plugins
HTML5: WebSockets

3. Rules
• multi-user (almeno bi-)
• applicazione 'semplice'
• grafica banale
• GWT
• weekend-app (da sviluppare in un paio
di giorni)

4. App
Simple Sample - PONG

5. WebSocket
http://dev.w3.org/html5/websockets/
http://websocket.org/
"... a technology providing for bi-
directional, full-duplex communications
channels, over a single Transmission Control
Protocol (TCP) socket."

6. WebSocket var uri= "ws://...."
var ws = new WebSocket(uri);
ws.onmessage = function ...
[onopen,onclose, onerror]
ws.send(msg)
HTTPServlet +
public WebSocket
doWebSocketConnect(HttpServletRequest r,...)
interface Websocket {
public onOpen(Connection cnt);
public onClose(...);
}
interface Websocket.OnTextmessage {
public void onMessage(String msg)
}
cnt.sendMessage(String msg)
8

7. WebSocket var uri= "ws://...."
var ws = new WebSocket(uri);
ws.onmessage = function ...
[onopen,onclose, onerror]
ws.send(msg)
HTTPServlet +
public WebSocket
doWebSocketConnect(HttpServletRequest r,...)
interface Websocket {
public onOpen(Connection cnt)
public onClose(...)
}
interface Websocket.OnTextmessage {
public void onMessage(String msg)
}
cnt.sendMessage(String msg)
8

8. schema Case 1:

9. schema Case 2:

10. pong
play !! :-)
jooink1.jooink.com/pong

11. schema Case 3:

12. schema Case 4:

13. That's all
folks !
That's all
:-)
jooink1.jooink.com/pong
jooink1.jooink.com/box2dTest