Introduction to Web Services

Transcription

1 Introduction to Web Services Jane Hsu Issues What is a Web Service? Why are Web Services interesting? What e-commerce business models do Web Services enable? What security and privacy issues need to be addressed for Web Services to be successful? What are the platforms supporting web services? Microsoft s.net Platform Sun J2EE Copyright (C) 2004 Jane Hsu 2

2 The basic business proposition of web services I want to be able to do business across the Internet with my customers, partners, and suppliers without having to know the intimate details of how they built their IT systems. Applications, programming languages, operating systems and hardware are still needed to build the Web services and the software that invokes them. Process Automation, Workflow, Data transformation, and Systems management are required to deploy Copyright (C) 2004 Jane Hsu 3 Web as Powerful Archive Copyright (C) 2004 Jane Hsu 4

3 Example: Yahoo! Stock Ticker Vast databases of historical stock prices accessible at Browser-oriented userfriendly displays Programs need to mimic users to request the information and then scrape the screens Inefficient and fragile Need a better mechanism! Copyright (C) 2004 Jane Hsu 5 Service Oriented Architecture Service Requestors Find Bind Internet Publish Service Providers Service Brokers Legacy System Copyright (C) 2004 Jane Hsu 6

4 Loosely-Coupled Web Applications XML/HTTP Web Services XML/HTTP XML/HTTP Copyright (C) 2004 Jane Hsu 7 Interoperability Intra-business: EAI Inter-business: B2Bi Supply chain management Copyright (C) 2004 Jane Hsu 8

5 Software Design Principles Abstraction Abstract & reuse useful functions in programs Abstraction hides implementation details Componentization Share code among programs by creating reusable software components Save time coding, debugging & testing Reusable components have value Components are local (i.e. live on your machine) Copyright (C) 2004 Jane Hsu 9 Componentizing To help different software applications communicate with one another Earlier development efforts COM (Microsoft) CORBA (Sun/Java) Web services are based on key standards Extensible Markup Language (XML) Simple Object Access Protocol (SOAP) Universal Description, Discovery and Integration (UDDI) Web Services Description Language (WSDL) Copyright (C) 2004 Jane Hsu 10

6 Software Engineering Coverage Web Services DCOM Java RMI Message Oriented Middleware CORBA Subroutine RPC DLL Centralized Client-Server Distributed Objects Web Services Black box Standard interface Network standards Open directory Copyright (C) 2004 Jane Hsu 11 Distributed Component Technology CORBA DCOM Java RMI SOAP Communication IIOP RPC IIOR or JRMP HTTP Message Format CDR NDR Java Ser. Format XML Spec. Language OMG IDL IDL Java WSDL Search Mechanism Naming Service Windows Registry RMI Registry UDDI Copyright (C) 2004 Jane Hsu 12

7 Web Services A web service is any software component that Is available over the Internet Programming the Web Remote procedure calls over the Web Web sites with no user interface Uses standard web messaging protocols (XML/SOAP) Is platform independent. i.e. Components are not tied to any one operating system or programming language. Enables highly distributed information systems Copyright (C) 2004 Jane Hsu 13 Web Services vs. Web Applications Web Services Web Application Interface program-program human-program Language XML HTML Service Index Search vis UDDI Search via search engine Application domain B2B B2C Protocols SOAP + HTTP/HTTPS/SMTP HTTP/HTTPS Copyright (C) 2004 Jane Hsu 14

8 Features of Web Services Services as Components reuse Platform-Free Standards-based Open Standards SOAP UDDI WSDL etc. Dynamic Integration On-demand Out-sourced Interoperability Incremental Deployment Copyright (C) 2004 Jane Hsu 15 Why will Web Services Succeed? Real Business Value is Delivered! Allows for Applications on demand & Utility-based Computing Faster deployments, Lower skill levels, Faster ROI Based on real and open Standards with ubiquity TCP/IP, HTTP, XML, SOAP, WSDL... Utilizes existing infrastructure We made the right choices this time Loose coupling, simple, business driven Early Industry Deployments Major Vendors totally committed (IBM, Microsoft, Sun, etc.) Customers already in production using web services Fastest Adoption rate of any technology in a long time Can cut cost of integration by up to 20% (McKinsey) -- the single biggest IT cost New business models & types of applications are possible Copyright (C) 2004 Jane Hsu 16

9 Three Standards Based on XML UDDI (Universal Description Discovery and Integration) Yellow pages directory for services White/green pages WSDL (Web Service Description Language) Document describing the message exchange contract SOAP (Simple Object Access Protocol) XML-based protocol for messaging Copyright (C) 2004 Jane Hsu 17 Web Services Technology Stack Service Flow (WFMS) Service Discovery & Publication (UDDI) Service Description (WSDL) Service Invocation & Messaging (SOAP) XML (XML Schema, Namespace) Security (WS-Sec) Quality of Service Management Network (HTTP, SMTP, FTP) Copyright (C) 2004 Jane Hsu 18

10 Evolution of UDDI Goal: automated discovery and execution of e- commerce transactions Universal Business Registry (UBR) White pages: company contact information Yellow pages: categorization/standard taxonomies Green pages: technical information about services exposed Web service infrastructure UDDI.org is comprised of more than 200 major software developers and e-business leaders Copyright (C) 2004 Jane Hsu 19 White Pages Business Name Text Description list of multi-language text strings Contact info names, phone numbers, fax numbers, web sites Known Identifiers list of identifiers that a business may be known by D-U-N-S (UDDI registry generated unique number for each business) Copyright (C) 2004 Jane Hsu 20

11 Yellow Pages Business categories 5 standard taxonomies in Version 2.0 Industry: NAICS (Industry codes - US Govt.) Product/Services: Standard Industrial Classification, USPSC Location: Geographical taxonomy (GGC, ISOGT) Implemented as name-value pairs to allow any valid taxonomy identifier to be attached to the business white page Copyright (C) 2004 Jane Hsu 21 Green Pages New set of information businesses use to describe how to do e-commerce with them Nested model Business processes Service descriptions Binding information Programming/platform/implementation independent Services can also be categorized Copyright (C) 2004 Jane Hsu 22

12 More Details UDDI SOAP WSDL Copyright (C) 2004 Jane Hsu 23 BPEL: An Emerging Standard Goal: specification for automating complex business processes. BPEL (Business Process Execution Language for Web services) will make it easier for businesses to create Web services applications that automate multi-step business processes, e.g. insurance claims The proposal was led by IBM, Microsoft, BEA Systems, and SAP. Submitted to the OASIS (Organization for the Advancement of Structured Information Standards) technical committee under royalty-free terms. Copyright (C) 2004 Jane Hsu 24

13 Digital Trust Services Framework By VeriSign Authentication Authorization Transaction service, e.g. bill payment Security standards: XKMS (XML Key Management Specification) SAML (Security Assertions Markup Language) Copyright (C) 2004 Jane Hsu 25 The Web Programming Model More loosely coupled that traditional distributed programming models like RPC, DCOM, and CORBA. Simple Web client-server interaction Exchange Messages that carry MIME-typed data Semantics of a message can be modified using headers The destination of a message is specified indirectly using a URL, and this level of indirection can be leveraged to implement load balancing, session tracking and other features Copyright (C) 2004 Jane Hsu 26

14 Architectural Characteristics of WS Distributed Loosely-coupled Standards-based Process-centric Copyright (C) 2004 Jane Hsu 27 Promise of Web Service CIOs surveyed by Basex Inc. 60% expect their Web services initiatives to be profitable within the next two years. 90% see it happening within the next five years. Jupiter Media Metrix survey of IT managers 50% see web services technology as a way to cut software integration costs. Copyright (C) 2004 Jane Hsu 28

15 Web Services: The Trend A September survey of IT execs by Forrester Research reported that 85% of respondents planned to deploy Web services by Up from 71% a year ago. IT managers see web services technology as a way to cut software integration costs. Copyright (C) 2004 Jane Hsu 29 Web Services (In Practice) Web Service Consumer Find a Service Link to WSDL document How do we talk? (WSDL) yourservice.com/?wsdl XML with service descriptions Let me talk to you (SOAP) XML/SOAP BODY UDDI Web Service Design-Time or Dynamic Runtime Copyright (C) 2004 Jane Hsu 30

16 Web Services Platforms Application Servers: Provide tools for application development and Support efficient execution of applications.net Microsoft J2EE IBM WebSphere Oracle Oracle 9i Application Server Sun Sun ONE (iplanet) HP HP Web Service Platform, espeak BEA Systems WebLogic Sybase EAServer Open Source: JBoss, JOnAS Copyright (C) 2004 Jane Hsu 31 Web Services Supporters Microsoft.NET My Services IBM Sun HP BEA Systems Oracle Copyright (C) 2004 Jane Hsu 32

17 Microsoft Next year the software giant will release.net My Services, an initiative formerly known as HailStorm that will deliver content, shopping, banking and other services over a variety of devices ranging from cell phones to PCs and handhelds. The massive operation will employ a global network of Web servers to house all manner of personal information, including accounts, address books, credit card numbers and photographs. On the infrastructure end, Microsoft is selling a family of e-business software for companies to create and run Web services, which include its forthcoming Visual Studio.Net development tools. Copyright (C) 2004 Jane Hsu 33 IBM Big Blue has built support for Web services into its WebSphere application-server software and offers Visual Age tools for building applications. WebSphere includes technology that runs transactions for Web sites and links to IBM's DB2 database software, which stores vast amounts of corporate and Web information, and its Tivoli Web services manager, which monitors performance of such products. IBM's Global Services arm is also said to be planning a move into the hosting end of Web services. Copyright (C) 2004 Jane Hsu 34

18 Sun The company is building support for Web services standards SOAP, UDDI and WSDL into its iplanet e- business software products, including its applicationserver software. By the end of 2002, Sun will add the existing Web services standards into Java 2 Enterprise Edition (J2EE), the Java standard for writing business software. The company says it will also release a tool for building Web services next year and is working on technology that will allow Java-based Web services to be compatible with Microsoft's.Net operations. Copyright (C) 2004 Jane Hsu 35 HP The computing giant has the potential to be a major player, but it remains to be seen whether the hardware maker can make inroads into the software market. "HP and BEA are likely to have a significant play, and Sun's iplanet is making some headway and will eventually catch up. HP has an edge because they had the idea before with E-speak," said analyst Mike Gilpin of Giga Information Group. Copyright (C) 2004 Jane Hsu 36

19 BEA Systems BEA was not as focused on Web services as IBM a few years ago. As the market leader in application-server infrastructure software, BEA is typically one of the quickest to get products out, and is expected to be highly competitive. BEA WebLogic Server won the 2002 Web Services Journal Editor's Choice Awards. Best Web Services Application Server Best Middleware - BEA WebLogic BEA's integrated development environment simplifies the creation of Web services for a broad range of developers. Copyright (C) 2004 Jane Hsu 37 Oracle The database leader is moving in two directions on Web services. First it is adding support for XML, SOAP, UDDI and WSDL to its 9i database-management software, application-server software and development tools so that its customers can use Web services in new systems. Second, it is developing Web-outfitted versions of its sales and customer relationship management software. Oracle 9i Application Server Web Services Copyright (C) 2004 Jane Hsu 38

20 Web Services: Promises vs. Reality Promises Can compose services Distributed Platform-independent Heterogeneous Can be discovered via UDDI registry All potentially developed and deployed independently Reality Yes Yes Yes Yes?? Copyright (C) 2004 Jane Hsu 39 Web Services Online Resources W3C Web Services Standards SOAP document AXIS document WSDL document UDDI document Copyright (C) 2004 Jane Hsu 40

21 The Alphabet Soup of Web Services SOAP, UDDI, WSDL, XML GXA (Global XML Web Services Architecture) WS-Security WS-Routing WS-Referral WS-Policy WS-Addressing SDIG DIME (Direct Internet Message Encapsulation) SOA (Service Oriented Architecture) Copyright (C) 2004 Jane Hsu 41 Midterm Report Pick a specific topic from the list Sign up at Present it in class on March 14 th, 2004 Submit your slides Extra bonus Install and demonstrate how it works Comparison of competing technologies/platforms Maximum team size: 2 students Copyright (C) 2004 Jane Hsu 42