three - tier no more: integration - ready applications with ajax and ws samisa abeysinghe...
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Three - Tier No More: Integration - Ready Applications with AJAX and WS
Samisa Abeysinghe (samisa@wso2.com)
WSO2 Inc.
Who am I?
A developer Apache Axis2/C and Axis C++
Member of Apache Software Foundation
Software Architect WSO2 Inc.
Agenda
Three-tier to Two-tier
XMLHttpRequest Characteristics
Introducing SOAPHttpRequest
Consuming Web Services
WS-* Support
REST vs. SOAP
Present and the Future
Three-tier to Two-tier
Web ClientWeb Server
App Server
HTTP SOAP
Web ClientApp Server
HTTP / SOAP
Case for Dropping a Tier
Web services – SOAP over HTTP
Web browser can handle XML
Let browser talk SOAP
First Generation - XMLHttpRequest
Construct XML representing SOAP envelope
SOAP is XML<envelope>
<header>...headers...</header><body>...payload...</body>
</envelope>
Send over HTTP
Concerns
You need to build the request SOAP envelope
Need to strip SOAP in response
First Generation Example
xmlhttp = new XMLHttpRequest();
xmlhttp.open("POST", "http://api.google.com/search/beta2",true);
xmlhttp.onreadystatechange=function() { if (xmlhttp.readyState==4) { alert(xmlhttp.responseText) } }
xmlhttp.setRequestHeader("Man", "POST http://api.google.com/search/beta2 HTTP/1.1")
xmlhttp.setRequestHeader("MessageType", "CALL")
xmlhttp.setRequestHeader("Content-Type", "text/xml")
First Generation Example (Contd.) xmlhttp.send("<?xml version='1.0' encoding='UTF-8'?>"+"\n\n"+
'<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">'+
'<soapenv:Body>'+
'<ns1:doSpellingSuggestion xmlns:ns1="urn:GoogleSearch"'+
' soapenv:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"'+
' xmlns:xsi="http://www.w3.org/1999/XMLSchema-instance"'+
' xmlns:xsd="http://www.w3.org/1999/XMLSchema">'+
'<key xsi:type="xsd:string">TcP7PPxQFHJtaZQO2OzWIPwdu2bUjYKD</key>'+
'<phrase xsi:type="xsd:string">salvasion</phrase>'+
'</ns1:doSpellingSuggestion>'+
'</soapenv:Body>'+
'</soapenv:Envelope>')
Next Generation - SOAPHttpRequest
Let AJAX handle SOAP for you
You just worry about request payload and response payload
Inherited form XMLHttpRequest
Hence same familiar API
Benefit
SOAP envelope is handled for you
Behind the Scenes
Used Apache Axis2/C as base
Implemented a Firefox extension
Extended Firefox AJAX API
Works both on Windows and Linux
Planning on an ActiveX object to support Microsoft IE
Objectives for SOAPHttpRequest
Use an API similar to XMLHttpRequest
Shorten learning curve
Leverage the power of an existing SOAP engine
Axis2/C is written with integration in mind as a portable C library
Written to support full web services stack
Consuming Web Services Invoking Google spell checker:
// create request object
var req = new SOAPHttpRequest();
// set SOAP version to be SOAP 1.1
req.soapVer = 1.1;
// set callback to be called on response
req.onreadystatechange = listenStatus;
// set up endpoint information; syntax:open(method, uri, isAsynchronous)
req.open("POST", "http://api.google.com/search/beta2", false);
// send request with payload
req.send (reqContent);
Consuming Web Services - Payload XML payload build using DOM API
//create the root nodevar req_node = document.createElementNS ("urn:GoogleSearch", "ns1:doSpellingSuggestion" );req_node. setAttribute ("xmlns:xsd", "http://www.w3.org/2001/XMLSchema" );//create the node for keyvar key_node = document.createElement ("key");key_node. setAttributeNS("http://www.w3.org/2001/XMLSchema-instance", "type", "xsd:string" );var key_text = document.createTextNode (key );key_node.appendChild(key_text);//create the node for phrase|var phrase_node = document.createElement ("phrase");phrase_node. setAttributeNS("http://www.w3.org/2001/XMLSchema-instance", "type", "xsd:string" );var phrase_text = document.createTextNode (phrase);phrase_node. appendChild(phrase_text );//attach nodesreq_node. appendChild (key_node );req_node. appendChild (phrase_node );reqContent = req_node; //attach nodesreq_node. appendChild (key_node );req_node. appendChild (phrase_node );reqContent = req_node;
Consuming Web Services - Callback
Captures result// responseXML contains response domvar resultContent = req. responseXML;
// Process result content as you wishHandleResponse (resultContent);
XML in/out Model
<?xml version="1.0" encoding="UTF-8"?> <soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"> <soapenv:Header></soapenv:Header><soapenv:Body> <ns1:doSpellingSuggestion xmlns:ns1="urn:GoogleSearch" soapenv:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" xmlns:xsi="http://www.w3.org/1999/XMLSchema-instance" xmlns:xsd="http://www.w3.org/1999/XMLSchema"> <key xsi:type="xsd:string">wCumFQpQFHL7+coIxlNKUGtyVsgrVAnb</key> <phrase xsi:type="xsd:string">tungsston</phrase> </ns1:doSpellingSuggestion> </soapenv:Body></soapenv:Envelope>
<?xml version='1.0' encoding='UTF-8'?><SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/1999/XMLSchema-instance" xmlns:xsd="http://www.w3.org/1999/XMLSchema"> <SOAP-ENV:Body> <ns1:doSpellingSuggestionResponse xmlns:ns1="urn:GoogleSearch" SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"> <return xsi:type="xsd:string">tungsten</return> </ns1:doSpellingSuggestionResponse> </SOAP-ENV:Body> </SOAP-ENV:Envelope>
Request
Response
Non-Blocking
Set the third parameter of open to truereq.open("POST", "http://api.google.com/search/beta2",
true);
WS-* Support
Axis2/C designed to support WS-*
Concept of modules
WS-Addressing built in
WS-Security and WS-Reliable Messaging available as separate modules
Advantage of using Axis2/C as base
Any module available at C level freely available at AJAX level
Axis2 Architecture
WS-Addressing
SOAP Header sample<soapenv:Header xmlns:wsa="http://www.w3.org/2005/08/addressing"> <wsa:To>http://localhost:9090/axis2/services/echo</wsa:To> <wsa:Action>http://ws.apache.org/axis2/c/samples/echoString</wsa:Action> <wsa:MessageID>cb00ebf2-39ad-1db1-36e2-001125ce1ac4</wsa:MessageID></soapenv:Header>
Need for addressing in enterprise
reply to : where to send the reply
fault to : where to send the fault
e.g. Booking flight: send bill to finance, if error let me know
WS-Addressing with AJAX
// engage addressing
req.engage ( "addressing", "version" );
// set WSA action
req.options({ wsa_action:"http://ws.apache.org/axis2/c/samples/echoString" } );
API allows you to select the version Addressing specific parameters could
be set as options
REST vs. SOAP
REST and SOAP are different religions
Both have devotees
At 30,000 feet
REST is light weight; SOAP is heavy weight
REST QoS based on transport; SOAP has array of message level QoS options
Both has use cases
You will need SOAP for some use cases
Present
You can try WSO2 Tungsten Firefox (v 1.5.0.1) extension
Open source with Apache 2.0 license
http://dist.wso2.net/products/tungsten/ajax/xpi/installation.html
Can consume Web services with XML in/out model
WS-Addressing and WS-Security UsernameToken integrated
Can use both on Linux and Windows with Firefox
Future
Full WS-Security, MTOM and WS-RM support
ActiveX object for Windows IE
WS-Policy, WS-Eventing coming up with Axis2/C
Would be available to AJAX extension
Conclusion
Full power of Web services stack available to AJAX programmer
Familiar API
Based on well designed, proved Apache Axis2 Web services architecture
Designed by industry leaders
C implementation: fast and portable design
Links
• WSO2 Tungsten XPI– http://dist.wso2.net/products/tungsten/ajax/xpi/
• Apache Axis2/C– http://ws.apache.org/axis2/c/
• This Presentation– http://people.apache.org/~samisa/
Thank you
Time for Q&A
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