Web Services Architecture Presentation for ECE8813 Spring 2003 By: Mohamed Mansour.
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Web Services Architecture
Presentation for ECE8813Spring 2003By: Mohamed Mansour
What is a Web Service
Any piece of software that makes itself available over the Internet and uses a standardized XML messaging system
Roles
Service Provider Service Requestor Discovery Agencies
Wire Protocol
Transport HTTP (or other Internet protocols)
Packaging SOAP (or other packaging protocols)
Extensions Context, routing, policy
SOAP Example
<SOAP:Envelope xmlns:SOAP=http://schames.xmlsoap.org/soap/envelope/
<SOAP:Header>
<!– contents of header goes here -- >
</SOAP:Header>
<SOAP:Body>
<!– contents of body goes here -- >
</SOAP:Body>
End-to-End Scenario
Requestor
SOAP run-time
SOAP message
Network Layer
HTTP Request
Server (Provider)
SOAP run-time
Network Layer
Deliver HTTP
Dispatch to appropriateruntime
Description Stack
Interface, Implementation Described in a WSDL (Web Service Description
Language) document Minimum layers for any web service
Stack Components
WSDL Example<message name="GetStockQuotesSoapIn"> <part name="parameters" element="s0:GetStockQuotes" /> </message>
<message name="GetStockQuotesHttpPostOut"> <part name="Body" element="s0:ArrayOfQuote" /> </message>
<portType name="StockQuotesSoap"> <operation name="GetStockQuotes"> <input message="s0:GetStockQuotesSoapIn" /> <output message="s0:GetStockQuotesSoapOut" /> </operation></portType>
WSDL Example – contd.
<service name="StockQuotes"> <port name="StockQuotesSoap" binding="s0:StockQuotesSoap"> <soap:address location="http://www.swanandmokashi.com/HomePage/WebServices/StockQuotes.asmx" /> </port></service>
WSDL Example – contd.<binding name="StockQuotesSoap" type="s0:StockQuotesSoap"> <soap:binding transport="http://schemas.xmlsoap.org/soap/http" style="document" /> <operation name="GetStockQuotes"> <soap:operation soapAction="http://swanandmokashi.com/GetStockQuotes" style="document" /> <input> <soap:body use="literal" /> </input> <output> <soap:body use="literal" /> </output> </operation></binding>
WSDL Example – contd.
<service name="StockQuotes"> <port name="StockQuotesSoap" binding="s0:StockQuotesSoap"> <soap:address location="http://.... /> </port> <port name="StockQuotesHttpGet" binding="s0:StockQuotesHttpGet"> <http:address location="http://......" /> </port> <port name="StockQuotesHttpPost" binding="s0:StockQuotesHttpPost"> <http:address location="http://......" /> </port></service>
Description Stack – contd. Policy
additional description to specify the business context, qualities of service, security requirements and offerings, and management requirements.
Presentation how to render the input and output messages on a screen for a
user to interact with. This is particularly useful for rendering Web services to users on many different types of devices.
Orchestration An orchestration description reflects a simple choreography of
Web service invocations between two business partners to complete a multi-step business interaction.
Composition Service Level Agreements Business Level Agreements
Discovery Stack
Publication Providers produce their service descriptions in a
UDDI document. Direct publish (ftp, CD-ROM, …) UDDI registry
Discovery Discovery methods parallel publication methods
Inspection Web Service Inspection Language (WSIL) a de-centralized, light weight method
Resources
http://www.w3.org/TR/2002/ http://www.xmethods.com http://www.alphaworks.ibm.com/webservices http://www.microsoft.com/webservices http://java.sun.com/webservices http://www.borland.com/webservices
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