Three - Tier No More: Integration - Ready Applications with AJAX and WS

1

• Three - Tier No More Integration - Ready
  Applications with AJAX and WS
• Samisa Abeysinghe (samisa_at_wso2.com)
• WSO2 Inc.

2
Who am I?

• A developer Apache Axis2/C and Axis C
• Member of Apache Software Foundation
• Software Architect WSO2 Inc.

3
Agenda

• Three-tier to Two-tier
• XMLHttpRequest Characteristics
• Introducing SOAPHttpRequest
• Consuming Web Services
• WS- Support
• REST vs. SOAP
• Present and the Future

4
Three-tier to Two-tier
Web Client
Web Server
App Server
HTTP
SOAP
Web Client
App Server
HTTP / SOAP
5
Case for Dropping a Tier

• Web services SOAP over HTTP
• Web browser can handle XML
• Let browser talk SOAP

6
First Generation - XMLHttpRequest

• Construct XML representing SOAP envelope
• SOAP is XMLltenvelopegt ltheadergt...headers...lt/he
  adergt ltbodygt...payload...lt/bodygtlt/envelopegt
• Send over HTTP
• Concerns
• You need to build the request SOAP envelope
• Need to strip SOAP in response

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First Generation Example

• xmlhttp new XMLHttpRequest()
• xmlhttp.open("POST", "http//api.google.com/searc
  h/beta2",true)
• xmlhttp.onreadystatechangefunction() if
  (xmlhttp.readyState4) alert(xmlhttp.respons
  eText)
• xmlhttp.setRequestHeader("Man", "POST
  http//api.google.com/search/beta2 HTTP/1.1")
• xmlhttp.setRequestHeader("MessageType", "CALL")
• xmlhttp.setRequestHeader("Content-Type",
  "text/xml")

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First Generation Example (Contd.)

• xmlhttp.send("lt?xml version'1.0'
  encoding'UTF-8'?gt""\n\n"
• 'ltsoapenvEnvelope xmlnssoapenv"http//schemas.x
  mlsoap.org/soap/envelope/"gt'
• 'ltsoapenvBodygt'
• 'ltns1doSpellingSuggestion xmlnsns1"urnGoogleSe
  arch"'
• ' soapenvencodingStyle"http//schemas.xmlsoap.or
  g/soap/encoding/"'
• ' xmlnsxsi"http//www.w3.org/1999/XMLSchema-inst
  ance"'
• ' xmlnsxsd"http//www.w3.org/1999/XMLSchema"gt'
• 'ltkey xsitype"xsdstring"gtTcP7PPxQFHJtaZQO2OzWIP
  wdu2bUjYKDlt/keygt'
• 'ltphrase xsitype"xsdstring"gtsalvasionlt/phrasegt'
  
• 'lt/ns1doSpellingSuggestiongt'
• 'lt/soapenvBodygt'
• 'lt/soapenvEnvelopegt')

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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

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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

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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

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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
  syntaxopen(method, uri, isAsynchronous)
• req.open("POST", "http//api.google.com/search/bet
  a2", false)
• // send request with payload
• req.send (reqContent)

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Consuming Web Services - Payload

• XML payload build using DOM API//create the root
  nodevar req_node document.createElementNS
  ("urnGoogleSearch", "ns1doSpellingSuggestion"
  )req_node. setAttribute ("xmlnsxsd",
  "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-i
  nstance", "type", "xsdstring" )var key_text
  document.createTextNode (key )key_node.appendChi
  ld(key_text)//create the node for phrasevar
  phrase_node document.createElement
  ("phrase")phrase_node. setAttributeNS("http//ww
  w.w3.org/2001/XMLSchema-instance", "type",
  "xsdstring" )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

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Consuming Web Services - Callback

• Captures result// responseXML contains response
  domvar resultContent req. responseXML//
  Process result content as you wishHandleResponse
  (resultContent)

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XML in/out Model
Request

• lt?xml version"1.0" encoding"UTF-8"?gt
  ltsoapenvEnvelope xmlnssoapenv"http//schemas.x
  mlsoap.org/soap/envelope/"gt
  ltsoapenvHeadergtlt/soapenvHeadergtltsoapenvBodygt
  ltns1doSpellingSuggestion
  xmlnsns1"urnGoogleSearch" soapenvencodingStyle
  "http//schemas.xmlsoap.org/soap/encoding/"
  xmlnsxsi"http//www.w3.org/1999/XMLSchema-instan
  ce" xmlnsxsd"http//www.w3.org/1999/XMLSchema"gt
  ltkey xsitype"xsdstring"gtwCumFQpQFHL
  7coIxlNKUGtyVsgrVAnblt/keygt ltphrase
  xsitype"xsdstring"gttungsstonlt/phrasegt
  lt/ns1doSpellingSuggestiongt lt/soapenvBodygtlt/soa
  penvEnvelopegt

Response

• lt?xml version'1.0' encoding'UTF-8'?gtltSOAP-ENVE
  nvelope xmlnsSOAP-ENV"http//schemas.xmlsoap.org
  /soap/envelope/" xmlnsxsi"http//www.w3.org/1999
  /XMLSchema-instance" xmlnsxsd"http//www.w3.org/
  1999/XMLSchema"gt ltSOAP-ENVBodygt
  ltns1doSpellingSuggestionResponse
  xmlnsns1"urnGoogleSearch" SOAP-ENVencodingStyl
  e"http//schemas.xmlsoap.org/soap/encoding/"gt
  ltreturn xsitype"xsdstring"gttungstenlt/r
  eturngt lt/ns1doSpellingSuggestionResponse
  gt lt/SOAP-ENVBodygt lt/SOAP-ENVEnvelopegt

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Non-Blocking

• Set the third parameter of open to true
• req.open("POST", "http//api.google.com/search/bet
  a2", true)

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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

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Axis2 Architecture
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WS-Addressing

• SOAP Header sampleltsoapenvHeader
  xmlnswsa"http//www.w3.org/2005/08/addressing"gt
  ltwsaTogthttp//localhost9090/axis2/services/e
  cholt/wsaTogt ltwsaActiongthttp//ws.apache.org/
  axis2/c/samples/echoStringlt/wsaActiongt
  ltwsaMessageIDgtcb00ebf2-39ad-1db1-36e2-001125ce1ac
  4lt/wsaMessageIDgtlt/soapenvHeadergt
• 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

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WS-Addressing with AJAX

• // engage addressing
• req.engage ( "addressing", "version" )
• // set WSA action
• req.options( wsa_action"http//ws.apache.org/ax
  is2/c/samples/echoString" )
• API allows you to select the version
• Addressing specific parameters could be set as
  options

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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

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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/in
  stallation.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

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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

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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

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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/

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• Thank you
• Time for QA