Web Services Erdogan Dogdu CSC 4360 6360 Computer Science Department Georgia State University Adapted from Mark Sapossnek Boston Uni presentation Learning Objectives Understand the coming Web Services revolution Fundamentals of Web Services Be able to create and debug a Web Service Using the NET Framework SDK Using Visual Studio NET Using Sun Microsystem s Java Web Services Development Pack JWSDP Agenda Web Services Overview Underlying Technologies Developing a Web Service Consuming Web Services Miscellaneous NET My Services Demo using Sun s JWSDP Web Services Overview Business Today CEO challenges Revamp customer service Overhaul supply chain Speed up the decision process CIO challenges Reorient IT architecture Connect with a limitless number of external constituents Extend processes to external constituents Web Services Overview Internet Business Processes Span Companies Web Services Overview Technology Fabric Must Span Companies Too Web Services Overview Drivers Companies suppliers partners and customers must be able to work together Faster than ever before Over the Internet Or risk death by isolation Leverage Internet cost structure Web Services Overview Possible Solutions Distributed computing Web sites portals Web Services Web Services Overview Distributed Computing Client server model Doesn t scale Not secure Distributed object model Components packaging and interoperability Remoting remote method invocation COM CORBA Java RMI and EJB Not Internet friendly Interoperability issues poor non existent standards Tightly coupled still doesn t scale Web Services Overview Distributed Computing 3 tier Application Architecture Great way to build scalable Web applications But such applications are silos Integration is an afterthought They can be integrated behind the firewall Even that can be a problem They do not provide a way to integrate across the firewall i e over the Internet Web Services Overview Portals Ads Mail Other Calendar Svcs Weather Finance News Web Services Overview Portal Limitations No standard way to expose functionality Integration is expensive and error prone Hard to outsource Not designed to be used outside original scope The problem HTML is designed for presentation to people Can t repurpose it in a general reliable way Don t even think about screen scraping Web Services Overview What Is a Web Service The solution Web Services A Web Service exposes functionality to a consumer Over the Internet or intranet A programmable URL Functions you can call over the Internet Based on Web standards HTTP XML SOAP WSDL UDDI with more to come Can be implemented in any language on any platform Black boxes Component like reusable Web Services Overview What Is a Web Service A Web Service combines the best features of distributed computing and portals and eliminates the worst Provides a mechanism for invoking methods remotely Uses Web standards e g HTTP XML to do so Web Services Overview What Is a Web Service Web Services allow you to interconnect Different companies Many any devices Applications Different clients Not just browsers Distribution and integration of application logic Enable the programmable Web Not just the purely interactive Web Web Services are loosely coupled Web Services Overview What is a Web Service New paradigm for Internet development Deliver applications as services Richer customer driven experience Continuous delivery of value bits Third generation Internet Web Services Overview Evolution of the Web HTML HTML HTML XML HTML XML Generation 1 Generation 2 Generation 3 Static HTML Web Applications Web Services Web Services Overview Benefits Everyone Leverage existing infrastructure Build or buy development decisions Minimize development time costs Enterprises Integration imperative Dynamic easy B2B relationships New Web based businesses Greater personalization New services new revenue streams Be everywhere vs single destination Web Services Overview Possibilities Scenario Planning a trip Go to Expedia site or Travelocity or Log in Find the flights you want Don t have to reenter seat meal airline frequent flyer info System can find lowest price fare by looking at your calendar s Purchase tickets w o entering credit card Flight info automatically added to your calendar and your spouse s calendar Book rental car hotel w your preferences added to calendar On day of trip get notified of flight status via email toast pager cell phone Web Services Overview Application Model Partner Web Service Other Web Services Internet XML End Users YourCompany com Application Business Logic Tier Data Access and Storage Tier Other Applications Partner Web Service Web Services Overview Sample Web Services E commerce order books office supplies other products Track packages UPS FedEx Weather Maps Telephone redirection customizable rules and messages Agenda Web Services Overview Underlying Technologies Developing a Web Service Consuming Web Services Miscellaneous NET My Services Underlying Technologies XML Is the Glue h Tec Inn ov og l o n y I P TCP Connectivity ati on FTP E ma il Go pher Connect the Web L M T H Presentation Web P ages Browse the Web XML Connecting Applications Web Serv ices Program the Web Underlying Technologies Web Services Stack Standards Directory Publish Find Services UDDI Description Formal Service Descriptions WSDL Wire Format Service Interactions SOAP Universal Data Format XML Ubiquitous Communications Internet Simple Open Broad Industry Support Underlying Technologies Web Services Stack Discovery Directory allows potential clients to locate relevant Web Services UDDI A Description language defines the format of methods provided by a Web Service WSDL Underlying Technologies Web Services Stack UDDI Description WSDL http www ibuyspy com ibuyspycs InstantOrder asmx wsdl Request Service Description Return Service Description XML Wire Format Request Service Return Service Response XML SOAP Web Service Web Service Client Link to Discovery Document XML UDDI or other directory service Directory http www uddi org Locate a Service Underlying Technologies Web Service Wire Format The Web Service Wire Format specifies how specific messages are exchanged HTTP GET HTTP POST SOAP HTTP GET and HTTP POST use a minimal HTTP interface to invoke Web Services Limited support for data types SOAP provides a robust HTTP XML interface Extensive support for data types XML Overview XML Basics XML is designed to represent and transfer structured data In HTML p Jan 15 2000 p In XML
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