Soap

Simple Object Access Protocol (SOAP) by Kazi Huque

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Presentation Outline       

Definition Motivation Characteristics SOAP message format SOAP in code SOAP Security SOAP in action 2

What is SOAP? 

SOAP is a lightweight protocol intended for exchanging structured information in a decentralized, distributed environment. SOAP uses XML technologies to define an extensible messaging framework, which provides a message construct that can be exchanged over a variety of underlying protocols. The framework has been designed to be independent of any particular programming model and other implementationspecific semantics. 3

SOAP is the Foundation WS-Secure Conversation

WS-Policy

WS-Federation WS-Authorization WS-Trust

WS-Privacy

WS-Security SOAP 4

Simply Put... 

SOAP is a way for a program running in one operating system to communicate with a program running in either the same or a different operating system, using HTTP (or any other transport protocol) and XML.

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SOAP Messaging Framework 

XML-based messaging framework that is   

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1) extensible 2) interoperable 3) independent

Next we discuss these three characteristics in more detail

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Extensible 

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Simplicity remains one of SOAP's primary design goals SOAP defines a communication framework that allows for features such as security, routing, and reliability to be added later as layered extensions

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Interoperable 

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SOAP can be used over any transport protocol such as TCP, HTTP, SMTP SOAP provides an explicit binding today for HTTP

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Interoperable Cont…

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Independent 

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SOAP allows for any programming model and is not tied to RPC SOAP defines a model for processing individual, one-way messages SOAP also allows for any number of message exchange patterns (MEPs)

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One-Way Message

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Request/Response

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SOAP Message Format 

SOAP message consists of three parts: 

SOAP Envelope

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SOAP Header (optional)

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SOAP Body

From the http://schemas.xmlsoap.org/soap/envelope/ namespace 13

SOAP Envelope 

The SOAP Envelope construct defines an overall framework for expressing what is in a message and who should deal with it.

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SOAP Envelope Cont… 

The Envelope is the top element of the XML document representing the message. 



The Envelope element is always the root element of a SOAP message. The Envelope element contains an optional Header element followed by a mandatory Body element.

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SOAP Envelope Code <soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"> <soap:Header> <soap:Body> 16

SOAP Header 

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The Header element is a generic container for control information It may contain any number of elements from any namespace Header blocks should contain information that influences payload processing Header is optional 17

SOAP Header Code <soap:Header> <s:credentials xmlns:s="urn:examples-org:security"> <username>dave <password>evad

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SOAP Body 

The Body element represents the message payload

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SOAP Body Code <soap:Body> <x:TransferFunds xmlns:x="urn:examples-org:banking"> 22-342439 98-283843 100.00

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SOAP in Code SOAP Message Embedded in HTTP Request: <SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" SOAPENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"> <SOAP-ENV:Body> <m:GetLastTradePrice xmlns:m="Some-URI"> <symbol>DIS

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SOAP in Code Cont… SOAP Message Embedded in HTTP Response: <SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"/> <SOAP-ENV:Body> <m:GetLastTradePriceResponse xmlns:m="Some-URI"> 34.5

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SOAP Security 

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The SOAP specification does not define encryption for XML Web Services. This is left up to the implementer of the SOAP protocol.

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Issues About Security 

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Encryption places a dependency on the transport protocol Does the transport protocol support secure communication? What is the cost of encrypting all the data versus part of the data?

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SOAP Code with Encryption <%@ WebService Language="C#" Class="CreditCardService" %> using System.Web.Services; public class CreditCardService { [WebMethod] [EncryptionExtension(Encrypt=EncryptMode.Response)] public string GetCreditCardNumber() { return "MC: 4111-1111-1111-1111"; } } 25

Request Encrypted <soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <soap:Body>

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Response Encrypted <soap:Body> 83 151 243 32 53 95 86 13 190 134 188 241 198 209 72 114 122 38 180 34 194 138 16 97 221 195 239 86 26 152 94 27

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SOAP in Action Demo

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References 

Understanding SOAP Overall explanation of what SOAP is, and what it can do. http://msdn.microsoft.com/webservices/understanding/webservicebasics/default.aspx?pull =/library/en-us//dnsoap/html/understandsoap.asp

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W3C Note Explains how SOAP exchanges messages. Code level details. http://www.w3.org/TR/2000/NOTE-SOAP-20000508/

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