DemonstrationWorking ofIntroductionUse service interactionsExecution modelArchitectureweb servicesWebof web services
“A software system designed tosupport interoperable machine-to-machine interactionover a network. It has an interface described in amachine-processable format (specifically Web ServicesDescription Language WSDL). Other systems interactwith the web service in a manner prescribed by itsdescription using SOAP messages, typically conveyedusing HTTP with an XML serialization in conjunctionwith other Web-related standards."
By using Web services, your application can publish itsfunction or message to the rest of the worldWeb services use XML to code and to decode data, andSOAP to transport itWith Web services, .NET application on Win 2k serverssystem can connect with other java application.
Web services are application componentWeb services are platform independentWeb services are self-describingWeb services can be discovered using UDDIWeb services can be used by other applicationsXML is the basis for Web services
Remote Service request ServerDeveloper Web Service Service response
Architectural role Service provider Service requester Service registryInteraction Publish operation Find operation Bind operation
The basic Web services platform is XML + HTTP. XML provides a language which can be used between different platforms and programming languages and still express complex messages and functions. WSDL (Web Services DescriptionDiscovery and Integration) UDDI (Universal Description, Language)Web Service Object Access Protocol) SOAP (Simple Platform element
WSDL is written in XMLWSDL is an XML documentWSDL is used to describe Web servicesWSDL is also used to locate Web servicesIt specifies the location of the service and the operations(or methods) the service exposes.
Element Definition<type> The data types used by the web service<message> The messages used by the web service<port type> The operations performed by the web service<binding> The communication protocols used <binding type="glossaryTerms" name="b1"><message name="getTermRequest"> <soap:binding style="document" The <message> element defines the data elements of an operation. <part name="term" type="xs:string"/><portType name="glossaryTerms"> more parts. The/> Eachtransport="http://schemas.xmlsoap.org/soap/http" parts can be</message> can consist of one or message <operation> <operation name="setTerm"> compared to the parameters of a function call in a traditional <soap:operation soapAction="http://example.com/getTerm"/> programming language. message="newTermValues"/> <input name="newTerm"<message name="getTermResponse"> <input><soap:body use="literal"/></input> </operation> <part<output><soap:body use="literal"/></output> name="value" type="xs:string"/></portType ></message> </operation> </binding>
SOAP is a communication protocolSOAP is for communication between applicationsSOAP is a format for sending messagesSOAP communicates via InternetSOAP is platform independent
SOAP is language independentSOAP is based on XMLSOAP is simple and extensibleSOAP allows you to get around firewalls
Element Definition<envelope> identifies the XML document as a SOAP message<header> contains header information<body> call and response information <?xml version="1.0"?><soap:Envelope ww.w3.org/2001/12/soap-envelope" <soap:Envelope soap:encodingStyle=http://www.w3.org/2001/12/soap-encoding>xmlns:soap="http://www.w3.org/2001/12/soap-envelope”> <soap:Header> xmlns:soap="http://www.w3.org/2001/12/soap-envelope"<soap:Body> <m:Trans xmlns:m="http://www.w3schools.com/transaction/" soap:encodingStyle="http://www.w3.org/2001/12/soap-encoding"> <m:GetPrice xmlns:m="http://www.w3schools.com/prices"> soap:mustUnderstand="1">234 ... <m:Item>Apples</m:Item> </m:Trans> Message information goes here </soap:Header>... </m:GetPrice> ... ...</soap:Body> </soap:Envelope> </soap:Envelope></soap:Envelope>
Specification for a distributed registry of Web services.Platform independent, open frameworkUses WSDL to describe interfaces to web services.UDDI is seen with SOAP and WSDL as one of the threefoundation standards of web services.
UDDI is an open industry initiative enabling businessesto discover each other and define how they interactover the Internet
Broker WSDL UDDI WSDL Service Servicerequester provider SOAP
Where to find web service SERVER A DISCOVERY Web service is located in server B SERVICECLIENT How exactly to invoke SERVER B Description is send in WSDL WEB SOAP request for method SERVICE SOAP response Web service invocation
HTTP Web Server with .asmx Pages Web Server with Browser .aspx Pages HTTP EXE XMLP HTTP PROXY XMLClient Server Service Fig. Web Service Execution Model
Reusable application-components.Connect existing software.This allows us to hide the details of how a service isimplemented; only URL and data types are requiredIt is largely irrelevant to the client whether the service isdeveloped with Java or ASP.NET or if it is running onWindows, Linux or any other platform
Creating web servicesConsuming web services in web applicationsConsuming web services in windows applications