- Reverse Ajax
Reverse Ajax refers to an Ajax
design pattern that uses long-livedHTTP connections to enable low-latency communication between aweb server and a browser. Basically it is a way of sending data from client to server and a mechanism for pushing server data back to the browser. [cite book
title=Comet and Reverse Ajax: The Next Generation Ajax 2.0
first=Dave
last=Crane
coauthors=McCarthy, Phil
publisher=Apress
isbn=1590599985
year=2008
month=July
language=English] [cite web
url=http://today.java.net/pub/a/today/2007/03/22/developing-applications-using-reverse-ajax.html
title=Developing Applications using Reverse Ajax
first=Katherine
last=Martin
publisher=java.net, O'Reilly and CollabNet
date=2007-03-22 ]This server–client communication takes one of two forms:
* Client polling, the client repetitively queries (polls) the server and waits for an answer.
* Server pushing, a connection between a server and client is kept open, the server sends data when available.Reverse Ajax describes the implementation of any of these models, including a combination of both. The design pattern is also known as "Ajax Push", "Full Duplex Ajax" and "Streaming Ajax".
Examples
The following is a simple example. Imagine we have 2 clients and 1 server, client1 to sends the message "hello" to every other client.
With traditional Ajax (polling)::*client1 sends the message "hello":* server receives the message "hello":* client2 polls the server:* client2 receives the message "hello" :* client1 polls the server:* client1 receives the message "hello"
With reverse Ajax (pushing)::* client1 sends the message "hello":* server receives the message "hello":* server sends the message "hello" to all clients
Note that with reverse Ajax less traffic is generated and the message has been transferred with less delay (low-latency).
ee also
*Ajax
*BOSH
*Comet
*Icefaces
*Push technology
*Pull technology References
External links
* [http://www.obviously.com/tech_tips/slow_load_technique The Slow Load Technique/Reverse AJAX - Simulating Server Push in a Standard Web Browser]
* [http://gmapsdotnetcontrol.blogspot.com/2006/08/exploring-reverse-ajax-ajax.html Exploring Reverse Ajax]
* [http://ajaxian.com/archives/reverse-ajax-with-dwr Reverse Ajax with DWR (an Java Ajax framework)]
* [http://www.lightstreamer.com/Lightstreamer_Paradigm.pdf Changing the Web Paradigm - Moving from traditional Web applications to Streaming-AJAX]
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