WebSockets: The Current State of the Most Valuable HTML5 API for Java Developers
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WebSockets provide a standardized way for web browsers and servers to establish two-way communications channels over a single TCP connection. They allow for more efficient real-time messaging compared to older techniques like polling and long-polling. The WebSocket API defines client-side and server-side interfaces that allow for full-duplex communications that some popular Java application servers and web servers support natively. Common use cases that benefit from WebSockets include chat applications, online games, and real-time updating of social streams.
![WEBSOCKET INTERFACE
[Constructor(DOMString
url,
optional
(DOMString
or
DOMString[])
protocols)]
interface
WebSocket
:
EventTarget
{
readonly
attribute
DOMString
url;
//
ready
state
const
unsigned
short
CONNECTING
=
0;
const
unsigned
short
OPEN
=
1;
const
unsigned
short
CLOSING
=
2;
const
unsigned
short
CLOSED
=
3;
readonly
attribute
unsigned
short
readyState;
readonly
attribute
unsigned
long
bufferedAmount;
//
networking
[TreatNonCallableAsNull]
attribute
Function?
onopen;
[TreatNonCallableAsNull]
attribute
Function?
onerror;
[TreatNonCallableAsNull]
attribute
Function?
onclose;
readonly
attribute
DOMString
extensions;
readonly
attribute
DOMString
protocol;
void
close([Clamp]
optional
unsigned
short
code,
optional
DOMString
reason);
//
messaging
[TreatNonCallableAsNull]
attribute
Function?
onmessage;
attribute
DOMString
binaryType;
void
send(DOMString
data);
void
send(ArrayBufferView
data);
void
send(Blob
data);
};](https://image.slidesharecdn.com/websocketsprincetonjug-120726125018-phpapp02/85/WebSockets-The-Current-State-of-the-Most-Valuable-HTML5-API-for-Java-Developers-10-320.jpg)
WebSockets: The Current State of the Most Valuable HTML5 API for Java Developers
- 1. WEB SOCKETS CURRENT STATE FOR JAVA DEVELOPERS
- 2. Web SOCKETS CURRENT STATE FOR JAVA DEVELOPERS PRESENTED BY VIKTOR GAMOV
- 3. WEB SOCKETS AGENDA BIT OF MEET WEBSOCKETS Q&A HISTORY THE WEBSOCKETS IN ACTION SESSION ?
- 4. OPTIONS FOR “REALTIME” WEB “LEGACY” WEB POLLING LONG-POLLING STEAMING Browser sends HTTP requests at Browser sends a request to the regular intervals and server and the server keeps the Browser sends a complete immediately receives a request open for a set period request, but the server sends response. However, real- time of time. If a notification is and maintains an open data is often not that received within that period, a response that is continuously predictable, making response containing the updated and kept open unnecessary requests message is sent to the client. If indefinitely (or for a set period inevitable and as a result, a notification is not received of time) many connections are opened within the set time period, the and closed needlessly in low- server sends a response to message-rate situations terminate the open request.
- 5. WHAT IS WEBSOCKET “Reducing kilobytes of data to 2 bytes... and reducing latency from 150ms to 50 ms is far more than marginal. In fact, these two factors alone are enough to make WebSocket seriously interesting...” www.ietf.org/mail-archive/web/hybi/current/msg00784.html
- 6. WHAT IS WEBSOCKETS? WEB SOCKET STANDARD PROTOCOL CLIENT-SIDE API SERVER-SIDE API Websocket is a HTML5 specification True real-time server standardized technology introduces WebSocket updates. Expected large (described in RFC6455) client side object. No penetration in Java to support low-overhead plugin required. world with upcoming bidirectional traffic from JavaEE 7 spec and your Web browser. JSR-356
- 7. WEBSOCKET HANDSHAKE To Start full-duplex communication client should send UPGRADE request 1 2 3 4 SEND RECEIVE CHANGE LISTEN UPGRADE UPGRADE READYSTATE MESSAGE REQUEST RESPONSE TO OPEN EVENT
- 10. WEBSOCKET INTERFACE [Constructor(DOMString url, optional (DOMString or DOMString[]) protocols)] interface WebSocket : EventTarget { readonly attribute DOMString url; // ready state const unsigned short CONNECTING = 0; const unsigned short OPEN = 1; const unsigned short CLOSING = 2; const unsigned short CLOSED = 3; readonly attribute unsigned short readyState; readonly attribute unsigned long bufferedAmount; // networking [TreatNonCallableAsNull] attribute Function? onopen; [TreatNonCallableAsNull] attribute Function? onerror; [TreatNonCallableAsNull] attribute Function? onclose; readonly attribute DOMString extensions; readonly attribute DOMString protocol; void close([Clamp] optional unsigned short code, optional DOMString reason); // messaging [TreatNonCallableAsNull] attribute Function? onmessage; attribute DOMString binaryType; void send(DOMString data); void send(ArrayBufferView data); void send(Blob data); };
- 11. CLIENT-SIDE WEBSOCKET API var ws; if (window.WebSocket) { output("WebSocket supported in your browser"); ws = new WebSocket("ws://www.websockets.org"); // Set event handlers. ws.onopen = function () { output("onopen"); }; ws.onmessage = function (e) { // e.data contains received string. output("echo from server : " + e.data); }; ws.onclose = function () { output("onclose"); }; ws.onerror = function () { output("onerror"); }; } else {output("WebSocket not supported in your browser");}
- 12. JAVA EE 7 SERVER-SIDE API package org.javaee.glassfishwebsocket; import org.glassfish.websocket.api.annotations.WebSocket; import org.glassfish.websocket.api.annotations.WebSocketMessage; @WebSocket(path = "/echo") public class EchoBean { @WebSocketMessage public String echo(String message) { System.out.println("##################### Message received"); return message + " (from your server)"; } }
- 13. TOMCAT 7.0.29 SERVER-SIDE API SHOW THE CODE Not enough room for code in this slide ;-)
- 14. PROGRAMMING WEBSOCKETS Client-side frameworks ✦jquery.socket.js ✦https://github.com/flowersinthesand/jquery-socket/wiki ✦atmosphere.js ✦https://github.com/Atmosphere/atmosphere/wiki/jQuery.atmosphere.js-API ✦socket.io
- 15. WEBSOCKET SUPPORT JAVA-based Web servers with native support. The WebServer has API for WebSocket ✦Netty 3.3.x ✦Jetty 7.x, 8.x ✦Glassfish 3.1.2 ✦Tomcat 7.0.27
- 16. WHAT SHOULD WE DO? WE CAN DO IT!
- 17. WHAT IS ATMOSPHERE Atmosphere https://github.com/Atmosphere/atmosphere/ ✦portable framework for ✦long-polling ✦Streaming ✦Server-Send Events ✦WebSockets ✦can auto select best transport ✦abstracting from actual underlying container mechanism
- 18. THINKING ABOUT USE CASES ?
- 19. USE CASE OUR CLIENTS WebSockets really shine with following applications: ✦Live trading/sports ticker ✦Controlling medical equipment over the web ✦Chat applications ✦Multiplayer online games ✦Realtime updating social streams
- 20. BUNCH OF USEFUL LINKS ✦http://www.w3.org/TR/websockets/ MUST! ✦http://tools.ietf.org/html/rfc6455 MUST! ✦http://tomcat.apache.org/tomcat-7.0-doc/web-socket-howto.html ✦http://websocket-sdk.java.net/Introduction.html ✦https://github.com/Atmosphere/atmosphere/wiki/Supported- WebServers-and-Browsers ✦http://autobahn.ws/testsuite
- 21. Q AND A Q&A Put your questions
- 22. CONTACT US WWW.FARATASYSTEMS.COM [email protected]
- 23. FIND ME TWITTER GITHUB WWW.TWITTER.COM/GAMUSSA WWW.GITHUB.COM/GAMUSSA
- 24. THANK YOU THANK YOU FOR YOUR ATTENTION HTTP://WWW.FARATASYSTEMS.COM