web services ppt
TRANSCRIPT
Introduction to Web Services
Jane Hsu
Copyright (C) 2004 Jane Hsu 2
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 PlatformSun J2EE
Copyright (C) 2004 Jane Hsu 3
The basic business proposition of web services…
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
I want to be able to do business across the Internet withI want to be able to do business across the Internet withmy customers, partners, and suppliers my customers, partners, and suppliers
withoutwithout having to know the intimate details having to know the intimate details of how they built their IT systemsof how they built their IT systems..
Copyright (C) 2004 Jane Hsu 4
Web as Powerful Archive
Copyright (C) 2004 Jane Hsu 5
Example: Yahoo! Stock Ticker
Vast databases of historical stock prices accessible at http://finance.yahoo.com
Browser-oriented user-friendly displays
Programs need to mimic users to request the information and then “scrape the screens”
Inefficient and fragile
Need a better mechanism!
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Service Providers
Service Oriented Architecture
Service Requestors
ServiceBrokers
LegacySystem
InternetPublishFind
Bind
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Loosely-Coupled Web Applications
Web Services
XML/HTTP
XML/HTTPXML/HTTP
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Interoperability
Intra-business:
EAI
Inter-business:
B2Bi
Supply chain management
Copyright (C) 2004 Jane Hsu 9
Software Design Principles
AbstractionAbstract & reuse useful functions in programs
Abstraction hides implementation details
ComponentizationShare 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 10
Componentizing
To help different software applications communicate with one another
Earlier development effortsCOM (Microsoft)
CORBA (Sun/Java)
Web services are based on key standardsExtensible Markup Language (XML)
Simple Object Access Protocol (SOAP)
Universal Description, Discovery and Integration (UDDI)
Web Services Description Language (WSDL)
Copyright (C) 2004 Jane Hsu 11
Software Engineering
Web Services
Java RMI
Message Oriented Middleware
CORBA
RPC
DLL
Subroutine
DCOM
1970 1980 1991 1996 1996 2000
Coverage
Black box Standard interface Network standards Open directoryCentralized Client-Server Distributed Objects Web Services
Copyright (C) 2004 Jane Hsu 12
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 MechanismNamingService
WindowsRegistry
RMI Registry UDDI
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Web Services
A web service is any software component thatIs 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 14
Web Services vs. Web Applications
Web Services Web Application
Interface program-program human-program
Language XML HTML
Service Index Search vis UDDISearch via searchengine
Application domain B2B B2C
ProtocolsSOAP +HTTP/HTTPS/SMTP
HTTP/HTTPS
Copyright (C) 2004 Jane Hsu 15
Features of Web Services
Services as Componentsreuse
Platform-FreeStandards-based
Open StandardsSOAP、UDDI、WSDL etc.
Dynamic IntegrationOn-demandOut-sourced
InteroperabilityIncremental Deployment
Copyright (C) 2004 Jane Hsu 16
Why will Web Services Succeed?
Allows for Applications on demand & “Utility-based” ComputingFaster deployments, Lower skill levels, Faster ROI
Based on real and open Standards with ubiquityTCP/IP, HTTP, XML, SOAP, WSDL ...Utilizes existing infrastructure
We made the right choices this timeLoose coupling, simple, business driven
Early Industry DeploymentsMajor Vendors totally committed (IBM, Microsoft, Sun, etc.)Customers already in production using web servicesFastest Adoption rate of any technology in a long time
Can cut cost of integration by up to 20% (McKinsey) -- the single biggest IT costNew business models & types of applications are possible
Real Business Value is Delivered!Real Business Value is Delivered!
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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 18
Web Services Technology Stack
Service Flow (WFMS)
Service Discovery & Publication (UDDI)
Service Description (WSDL)
Service Invocation & Messaging (SOAP)
XML (XML Schema, Namespace)
Network (HTTP, SMTP, FTP)
Man
agem
ent
Qu
ality of S
ervice
Secu
rity (WS
-Sec)
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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
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White Pages
Business Name
Text Descriptionlist of multi-language text strings
Contact infonames, 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)
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Yellow Pages
Business categories5 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 22
Green Pages
New set of information businesses use to describe how to “do e-commerce” with them
Nested modelBusiness processes
Service descriptions
Binding information
Programming/platform/implementation independent
Services can also be categorized
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More Details
UDDI
SOAP
WSDL
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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 claimsThe 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 25
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 26
The Web Programming Model
More loosely coupled that traditional distributed programming models like RPC, DCOM, and CORBA.
Simple Web client-server interactionExchange 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 27
Architectural Characteristics of WS
Distributed
Loosely-coupled
Standards-based
Process-centric
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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 29
Web Services: The Trend
A September survey of IT execs by Forrester Research reported that
85% of respondents planned to deploy Web services by 2004.
Up from 71% a year ago.
IT managers see web services technology as a way to cut software integration costs.
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Let me talk to you (SOAP)Let me talk to you (SOAP)
Web Services (In Practice)
DesignDesign--Time or DynamicTime or Dynamic RuntimeRuntime
How do we talk? (WSDL)How do we talk? (WSDL)
http://http://yourservice.comyourservice.com/?WSDL/?WSDL
XML with service descriptionsXML with service descriptions
http://yourservice.com/svc1http://yourservice.com/svc1
XML/SOAP BODYXML/SOAP BODY
Web Web ServiceService
WebWebService Service
ConsumerConsumer
UDDIUDDI
Find a ServiceFind a Service
http://http://www.uddi.orgwww.uddi.org
Link to WSDL documentLink to WSDL document
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Web Services Platforms
Application Servers: Provide tools for application development and Support efficient execution of applications
.NET MicrosoftJ2EE
IBM WebSphereOracle Oracle 9i Application ServerSun Sun ONE (iPlanet)HP HP Web Service Platform, eSpeakBEA Systems WebLogicSybase EAServer
Open Source: JBoss, JOnAS
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Web Services Supporters
Microsoft .NET My Services
IBM
Sun
HP
BEA Systems
Oracle
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Microsoft
Next year the software giant will release .Net My Services, an initiative formerly known as HailStormthat 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 e-mail 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 34
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 35
Sun
The company is building support for Web services standards SOAP, UDDI and WSDL into its iPlanet e-business software products, including its application-server 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 36
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 37
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 ServerBest 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 38
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
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Web Services: Promises vs. Reality
PromisesCan compose servicesDistributedPlatform-independentHeterogeneousCan be discovered via UDDI registryAll potentially developed and deployed independently
RealityYesYesYesYes?
?
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Web Services Online Resources
W3C Web Services Standardshttp://www.w3c.org/2002/ws/
SOAP documenthttp://www.w3.org/TR/2003/REC-soap12-part0-20030624/
AXIS documenthttp://ws.apache.org/axis/java/architecture-guide.html
WSDL documenthttp://www.w3.org/TR/2003/WD-wsdl20-20031110
UDDI documenthttp://uddi.org/pubs/uddi-v3.0.1-20031014.htm
Copyright (C) 2004 Jane Hsu 41
The Alphabet Soup of Web Services
SOAP, UDDI, WSDL, XMLGXA (Global XML Web Services Architecture)
WS-SecurityWS-RoutingWS-Referral
WS-PolicyWS-AddressingSDIGDIME (Direct Internet Message Encapsulation)SOA (Service Oriented Architecture)
Copyright (C) 2004 Jane Hsu 42
Midterm Report
Pick a specific topic from the listSign up at http://www.csie.ntu.edu.tw/~r92109/pmwiki/pmwiki.php/Main/PresentList
Present it in class on March 14th, 2004Submit your slides
Extra bonusInstall and demonstrate how it works
Comparison of competing technologies/platforms
Maximum team size: 2 students