The AJAX Architecture and Scripting Services with E4X

61 Pages·2005·1.28 MB·English

by  Wayne Kovsky

Colorado Software Summit: October 23 – 28, 2005 © Copyright 2005, WSO2 Inc.
The AJAX Architecture and
Scripting Services with E4X
Paul Fremantle
VP of Technology
WSO2
[email protected]
www.wso2.com
Thanks to Anthony Elder, IBM, who co-wrote the examples,
and IBM who supported much of the effort in putting this together
Paul Fremantle — The AJAX Architecture and Scripting Services with E4X Page (cid:1)
Colorado Software Summit: October 23 – 28, 2005 © Copyright 2005, WSO2 Inc.
About the Presenter
(cid:1) Ex-IBM Senior Technical Staff Member
(cid:3) Led the creation and development of
• IBM Web Services Gateway
• Web Services Invocation Framework
• JWSDL / WSDL4J
(cid:1) VP of Technology at WSO2
(cid:3) www.wso2.com
(cid:3) A startup aiming to develop and support leading edge Open Source
Web services software
• Provides support, training and consultancy for Apache Axis 1.x
(cid:1) Co-Chair of the OASIS WS-Reliable eXchange Technical Committee
(cid:3) http://www.oasis-open.org/committees/tc_home.php?wg_abbrev=ws-rx
(cid:1) Co-author of “Building Web Services in Java 2nd Edition”
(cid:1) Blog http://www.bloglines.com/blog/paulfremantle
Paul Fremantle — The AJAX Architecture and Scripting Services with E4X Page (cid:1)
Colorado Software Summit: October 23 – 28, 2005 © Copyright 2005, WSO2 Inc.
Contents
(cid:1) Introducing AJAX
(cid:1) Advantages
(cid:1) Building AJAX clients for REST services
(cid:1) Rest and SOAP
(cid:1) Introducing E4X
(cid:1) Sample browser code
(cid:1) Writing server logic in E4X
(cid:1) Conclusions
Paul Fremantle — The AJAX Architecture and Scripting Services with E4X Page (cid:1)
Colorado Software Summit: October 23 – 28, 2005 © Copyright 2005, WSO2 Inc.
Introducing AJAX
(cid:1) Asynchronous JavaScript and XML
(cid:3) The practice of using “under the covers” XML/HTTP
conversations to enrich a web page
(cid:3) The requests do not constitute page refresh
(cid:3) Results in more intuitive applications
(cid:3) Remember the “network is the computer”?
• The network is the application?
(cid:3) Examples:
• Google – Maps, Mail, autocomplete
• Google maps can scroll round indefinitely, pulling in
information from the network as needed
Paul Fremantle — The AJAX Architecture and Scripting Services with E4X Page (cid:1)
Colorado Software Summit: October 23 – 28, 2005 © Copyright 2005, WSO2 Inc.
Why Use AJAX?
(cid:1) Er… it’s the latest thing?
(cid:1) Subliminal validation
(cid:3)Checking entries while the user is typing
(cid:3)Prompting users with possible answers
(cid:3)Minimising network delays by interleaving
network activity with user activity
Paul Fremantle — The AJAX Architecture and Scripting Services with E4X Page (cid:1)
Colorado Software Summit: October 23 – 28, 2005 © Copyright 2005, WSO2 Inc.
Normal Web Application
User active
User waiting
GET
HTML form (new page)
User active
User waiting browser POST server
HTML form (validated)
User active
User waiting POST
HTML response
User active
User gets form, submits, returned with marked
errors, resubmits, reads response
Paul Fremantle — The AJAX Architecture and Scripting Services with E4X Page (cid:1)
Colorado Software Summit: October 23 – 28, 2005 © Copyright 2005, WSO2 Inc.
AJAX Web Application
User active
User waiting GET
HTML form (new page)
browser server
XMLHttpRequest
User active
XMLHttpRequest
XMLHttpRequest
XMLHttpRequest
- No page refreshes – user is always in control
- Validation of one field can happen while user is
typing another.
- Validation can be less intrusive (like changing the
graphical attributes
Paul Fremantle — The AJAX Architecture and Scripting Services with E4X Page (cid:1)
Colorado Software Summit: October 23 – 28, 2005 © Copyright 2005, WSO2 Inc.
How Does It Work?
(cid:1) XMLHttpRequest
(cid:3)Introduced in IE
(cid:3)Supports programmatic sending of HTTP
requests and parsing the results
(cid:3)Not tied to XML – but much easier to correctly
parse
(cid:3)Usually uses DOM for parsing the XML
Paul Fremantle — The AJAX Architecture and Scripting Services with E4X Page (cid:1)
Colorado Software Summit: October 23 – 28, 2005 © Copyright 2005, WSO2 Inc.
Getting an XMLHttpRequest
(cid:2) Er… there is no standard, cross-browser, single
syntax (cid:1)
(cid:2) Microsoft syntax:
(cid:4) xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
• or
(cid:4) xmlhttp = new ActiveXObject(“Msxml2.XMLHTTP”);
(cid:2) Everyone else
(cid:4) xmlhttp = new XMLHttpRequest();
Paul Fremantle — The AJAX Architecture and Scripting Services with E4X Page (cid:1)
Colorado Software Summit: October 23 – 28, 2005 © Copyright 2005, WSO2 Inc.
One Size Fits All Code
var xmlhttp=false;
try {
xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
} catch (e) { try {
xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
} catch (E) { xmlhttp = false; }
}
if (!xmlhttp && typeof XMLHttpRequest!='undefined') {
xmlhttp = new XMLHttpRequest();
}
(cid:2) Thanks to:
• http://jibbering.com/2002/4/httprequest.html
Paul Fremantle — The AJAX Architecture and Scripting Services with E4X Page (cid:2)(cid:1)