SOAP TECHNOLOGY

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SOAP TECHNOLOGY

• What is SOAP ?
• SOAP is a simple, lightweight XML protocol for
  exchanging exchanging structured and typed
  information on the Web
• Extensible
• No application semantics and no transport
  semantics

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Who is drafting SOAP ?

• UserLand, Ariba, CommerceOne, Compaq,
  Developmentor, HP, IBM, IONA, Lotus, Microsoft,
  SUN and SAP.
• SOAP specification v1.1 already a W3C standard.
  v1.2 has recently been submitted.

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Why SOAP?

• Important need in Internet application
  development to allow communication between apps.
• The politics of serialization Several large
  factions each loyal to its own particular RPC (
  remote procedure call ) protocol - DCOM, CORBA ,
  Java RMI
• SOAP addresses the interoperability issue at the
  data serialization level

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Bringing down the walls

• These systems could interact using bridges but
  they add costs and hurt performance.
• Made decisions to standardize on one or the other
  then used message-oriented middleware for
  integration.
• If Web browsers can, why not remote services?
• SOAP - simplicity, flexibility,
  platform-neutrality and text-based.

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RPC revisited

• SOAP - a standard way of serializing the info.
  needed to invoke remote services into a format
  and transported across the wire, then recreated
  at destination.
• To understand SOAP better a look at DCOMs RPC
  architecture.
• Primary design goal of DCOM was location
  transparency.

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DCOM Architecture

• Location transparency in DCOM using the
  proxy/stub architecture. DCOM uses the NDR
  serialization scheme.
• SOAP uses XML to structure the data serialization.

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SOAP and...HTTP ?!

• More than a data serialization format to do real
  RPC.transfer messages to the server and return
  the response.
• DCOM and CORBA are incompatible when addressing
  endpoints, activating remote objects...
• HTTP most conducive Internet Protocol for RPC via
  SOAP msgs
  -URLs,Synch. Blocking, Scalable ,Secure

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The Firewall blues

• DCOM and CORBA IIOP not firewall friendly, use
  oddly-numbered ports etc.
• HTTP traffic over port 80 usually can talk
  through firewalls.
• SOAP messages treated as a new MIME type to be
  carried in a HTTP payload so HTTP headers
  indicate packet has SOAP request , better
  firewall control.

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SOAP building block
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SOAP Building block ( contd )

• A SOAP message is an ordinary XML document.
• The XML document contains the following XML
  elements
• - A SOAP envelope , defines message content
• - A SOAP header(optional), contains header
  information
• - A SOAP body, that contains call and response
  information

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A SOAP Example

• A SOAP request embedded in an HTTP Request
• ltSOAP-ENVEnvelopegt
• lt SOAP-ENVBodygt
• ltxmlnsmhttp//www.stock.org/stock/gt
• lt mGetStockPricegt
• lt StockNamegtIBMlt/StockNamegt
• lt/mGetStockPricegt
• lt/SOAP-ENVBodygt
• lt/SOAP-ENVEnvelopegt

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A SOAP Example (Contd )

• A SOAP response embedded in an HTTP Response
• ltSOAP-ENVEnvelopegt
• lt SOAP-ENVBodygt
• ltxmlnsmhttp//www.stock.org/stock/gt
• lt mGetStockPriceResponsegt
• lt StockNamegt113.81lt/StockNamegt
• lt/mGetStockPriceResponsegt
• lt/SOAP-ENVBodygt
• lt/SOAP-ENVEnvelopegt

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SOAP Summary

• SOAP is
• - a lightweight comm. protocol
• - is based on XML
• - designed to communicate via HTTP
• - not tied to any component technology or
  programming language.
• - simple and extensible
• - a W3C standard

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Thankyou!