Web Services Overview

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1 Web Services Overview Dr. Kanda Runapongsa Department of Computer Engineering Khon Kaen University 1 Outline What is Web Services? Why Web Services? Where is Web Services? Web Services Architecture and Standards Web Services Implementation and Tools 2 Dr. Kanda Runapongsa, Khon Kaen University 1

2 In Search of a Definition Web Services mean different things to different people Web Services = == = Web Application? Web Services Æ Computer to Computer Web Application Æ Computer to Human beings Web Services = == = e-commerce? e E-Commerce needs to also consider security 3 Web Services Definition by W3C A Web service is a software application identified by a URI Support direct interactions with other software applications Using XML based messages via Internet-based protocols 4 Dr. Kanda Runapongsa, Khon Kaen University 2

3 Distributed Computing Evolution 5 Traditional RPC vs. Web Services 6 Dr. Kanda Runapongsa, Khon Kaen University 3

4 Web Application vs. Web Services 7 Characteristics of Web Services XML based everywhere Message-based Programming language independent Could be dynamically located Could be dynamically assembled or aggregated Accessed over the internet Loosely coupled Based on industry standards 8 Dr. Kanda Runapongsa, Khon Kaen University 4

5 Service Aggregation User Stock Service Portal Input: Symbol Output: Price, News, Trade SetTrade Input: Symbol Output: Price News feed 1 Input: Symbol Output: News links Brokerage 1 Input: Symbol, Price, Qty Output: Analysis.. Brokerage n Input: Symbol, Price, Qty Output: Analysis News feed n Input: Symbol Output: News links 9 Outline What is Web Services? Why Web Services? Where is Web Services? Web Services Architecture and Standards Web Services Implementation and Tools 10 Dr. Kanda Runapongsa, Khon Kaen University 5

6 Why Web Services? Platform neutral Accessible in a standard way Accessible in an interoperable way Use simple and ubiquitous tools Relatively cheap Simplify enterprise integration 11 Why Web Services? Interoperable Connect across heterogeneous networks using ubiquitous web-based based standards Economical Recycle components, no installation and tight integration of software Automatic No human intervention required even for highly complex transactions Accessible Legacy assets & internal apps are exposed and accessible on the web Available Services on any device, anywhere, anytime Scalable No limits on scope of applications and amount of heterogeneous applications 12 Dr. Kanda Runapongsa, Khon Kaen University 6

Web Services Usage Example Growing need for a standard lightweight infrastructure for data exchange in e-business e applications Distributor Supplier XML XML

7 Web Services Usage Example Growing need for a standard lightweight infrastructure for data exchange in e-business e applications Distributor Supplier XML XML Internet XML Manufacturing Factory XML Logistics 13 Impact of Web Services on Software Application DisIntegration Integration 14 Dr. Kanda Runapongsa, Khon Kaen University 7

8 Macro Web Services Virtual Systems A web service is accessed programmatically by applications or other web services Bank Balance Net worth Stock Position Portfolio Biz News News World News 15 Micro Web Services Virtual Apps A web service is accessed programmatically by applications or other web services Spell Check Grammar Dictionary Word Processing C:\... Publishing 16 Dr. Kanda Runapongsa, Khon Kaen University 8

9 Three Laws of Computing Moore s s Law Computing power doubles every 18 months Gilder s s Law Network bandwidth capacity doubles every 12 months Metcalfe s s Law (Net Effect) Value of network increases exponentially as number of participants increases 17 Impact on Integration Trigger the N etwork Effect Metcalfe s s Law: Value of network increases exponentially as number of participants increases Custom integration Web Services 18 Dr. Kanda Runapongsa, Khon Kaen University 9

10 Myths about Web Services Web Services are something completely new: Not True! You have to write Web Services from scratch: Not True! J2EE Platform does not support web services: Not True! 19 Myth: Web Services is a New Concept Web services is distributed computing all over again only now it is based on the web Concept Interface Description Distributed Computing (CORBA/ Java) CORBA IDL, Java Interface Basic Web Services WSDL RPC Support Service Registry Messaging support Transaction support ORBS, ldl2java compilers, rmic CORBA naming service, JDNI CORBA Event/ Notification service, JMS CORBA Transaction service, JTS SOAP, compilers for WSDL UDDI?? 20 Dr. Kanda Runapongsa, Khon Kaen University 10

11 Other Popular Myths Surrounding Web Services Web services require only SOAP, WDL, UDDI We need more high-level semantics Web services are based on the RPC paradigm Document-driven model would be more popular communication model Web services must be based on HTTP Other transports such as SMTP can also be used 21 Outline What is Web Services? Why Web Services? Where is Web Services? Web Services Architecture and Standards Web Services Implementation and Tools 22 Dr. Kanda Runapongsa, Khon Kaen University 11

12 State of Web Services Technology/ Standards are still evolving SOAP, WSDL, UDDI are not enough Business web services is the next big thing, but more works are needed in Quality of Service, management Security, transaction, state and user context Work flow, Identify management Provisioning, Accounting Will be adopted in phases 23 Web Services Adoption Phases 1 st phase (current state) 2 nd 3 rd Concerted deployment internally within an organization mainly for interoperability SOAP over HTTP nd phase (1 to 2 years) Selective and non-aggregate deployment with trusted outside business partners Private registry deployment rd phase (at least 3 to 4 years away) Wider, more dynamic and aggregate deployment with outside business partners Public registry deployment 24 Dr. Kanda Runapongsa, Khon Kaen University 12

13 Web Services Adoption Phases 1 st phase Simple Web Services (N ow) Consumer-focused, stateless, SOAP over HTTP/ S 2 nd phase EAI Web Services (Begun) Deployed within organization boundaries to enable internal integration 3 rd phase Business Web Services (2004?) Deployed extranets to enable business transactions with trading partners, suppliers, and customers, ebxml & UBL 25 J2EE Business Web Services Service implementation platform standard ebxml and UBL Business web services standards More than 16 vendors and several open source projects support ebxml Australian gas industry uses ebxml Now Liberty Project Identify system standard 26 Dr. Kanda Runapongsa, Khon Kaen University 13

14 Business Web Services (B2 ) Architectural Components (ebxml) B2B collaboration Secure and reliable message delivery Non-repudiation Partner profile Repository for business data objects 27 Simple Web Services vs. B2B Collaboration (ebxml) Simple Web Services Simple interaction Consumer oriented Short-living process No business collaboration No partner profile Not secure, not reliable Does not support non- repudiation B2B Collaboration Complex interaction Business oriented Long-running process Supports business collaboration Supports partner profile Secure and reliable Supports non-repudiation 28 Dr. Kanda Runapongsa, Khon Kaen University 14

15 EAI vs. B2B Collaboration (ebxml) EAI Within a business organization Centralized control Implicit contract Small number of business process and participants B2B Collaboration Between business organizations Distributed control Explicit contract Potentially large number of business processes and participants 29 Trends Towards Service Orientation Evolution of EAI to web service standards XML RPC Î Asynchronous XML Messaging Towards de-centralization Componentized services Composable and composite services Data encapsulated within components Data ownership follows component ownership Brokered web services Flexible relationships Î Adaptive business 30 Dr. Kanda Runapongsa, Khon Kaen University 15

16 Outline What is Web Services? Why Web Services? Where is Web Services? Web Services Architecture and Standards Web Services Implementation and Tools 31 (Simplified) Web Service Architecture 1. Service Registers PUBLISH Registry 2. Client request Service Location FI ND Web Service Provider Service Client 3. Client calls Service BI ND 32 Dr. Kanda Runapongsa, Khon Kaen University 16

17 Operation Models for Web Services Web Service Provider Creates the Web service typically as SOAP- based service interfaces Deploys the service and make them available for invocation over a network Describes the Web service as a WSDL-based service description Registers the WSDL-based service description with a service broker, which is typically a UDDI registry 33 Operation Models for Web Services Registry Stores the service description as binding templates and URLs to WSDLs located in the service provider environment List various service types, descriptions, and locations of the services that help the service requesters find and subscribe to the required services 34 Dr. Kanda Runapongsa, Khon Kaen University 17

18 Operation Models for Web Services Service Clients Locates the required services by querying the UDDI registry Obtains the binding information and the URLs to identify the service provider Invokes the service provider Retrieves the WSDL Service description for those registered services Communicate with the service provider Exchange data or messages by invoking the available services in the service container 35 Web Services Interaction Diagram Request WSDL location 1 UDDI Registry 2 Dow nload WSDL WSDL Send SOAP messages With XML documents 3 Web Services 36 Dr. Kanda Runapongsa, Khon Kaen University 18

19 Simple Object Access Protocol (SOAP) Wire protocol similar to IIOP for CORA JRMP for RMI XML is used for data encoding Text based protocol vs. binary protocol Supports XML-based RPC 37 What SOAP is Not Not a component model So, it will not replace objects and components, i.e., EJB, JavaBeans Not a programming language So it will not replace java Not a solution for all So it will not replace other distributed computing technologies such as RMI 38 Dr. Kanda Runapongsa, Khon Kaen University 19

20 What does SOAP Define? Message Envelope Encoding Rules RPC Convention Binding with underlying protocols 39 SOAP Message Format SOAP Message Primary MIME part (text/xml) Attachment Attachment Attachment SOAP Envelope SOAP Header Header Entry Header Entry SOAP Body Body Entry Body Entry 40 Dr. Kanda Runapongsa, Khon Kaen University 20

21 SOAP Message Envelope Encoding information Header Optional Could contain context knowledge Security Transaction Body RPC methods and parameters Contains application data 41 SOAP Encoding Rules of expressing application-defined data types in XML Based on W3C XML schema Simple values Built-in in types from XML Schema, Part 2 (simple types, enumerations, arrays of bytes) Compound values Structs, arrays, complex types 42 Dr. Kanda Runapongsa, Khon Kaen University 21

22 What is WSDL? XML language for describing web services Web service is described as A set of communication endpoints (ports) Endpoint is made of two parts Abstract definitions of operations and messages Concrete binding to networking protocol (and corresponding endpoint address) and message format Why this separation? Enhance reusability (as we will see in UDDI reference to WSDL document) 43 Why WSDL? Enables automation of communication details between communicating partners Machines can read WSDL Machines can invoke a service defined in WSDL Discoverable through registry Arbitration 3 rd party can verify if communication conforms to WSDL 44 Dr. Kanda Runapongsa, Khon Kaen University 22

23 WSDL Document Example Simple service providing stock quotes A single operation called GetLastTradePrice Deployed using SOAP 1.1 over HTTP Request takes a ticket symbol of type string Response returns price as a float 45 Service Architecture 1. Service Registers PUBLISH UDDI Registry 2. Client request Service Location FI ND Web Service Provider 3. Client calls Service BI ND Service Client UDDI defines a way to publish and find information about Web services 46 Dr. Kanda Runapongsa, Khon Kaen University 23

24 UDDI (Universal Description, Discovery and Integration) White pages Address, contact, and known identifiers Yellow pages Industrial categorizations Industry: NAICS (Industry codes US Govt.) Product/ Services: UN/ SPSC (ECMA) Location: Geographical taxonomy Green pages Technical information about services 47 Web Services Protocols XML / Web services messages are formatted using XML SOAP / / xp/ Group Simple Object Access Protocol Defines the standard format for XML messages Functionally similar to RPC, CORBA, RMI 48 Dr. Kanda Runapongsa, Khon Kaen University 24

25 Web Services Protocols WSDL / / ws/ desc Web Services Description Language Describes a web services as a collection of ports and operations XML interface document similar to CORBA IDL or RMI/ EJB remote interface UDDI / Universal Description, Discovery and Integration Provides a searchable registry of web services Similar, but broader in scope compared with CORBA or JNDI registry 49 Other Web Services Standards ebxml A global electronic market place where enterprises of any size, anywhere can: Find each other electronically Conduct business through exchange of XML based business messages Business Language UBL (Universal Business Language) Business collaboration and choreography ebxml BPSS, ebxml CPP/ CPA, BPML, WSFL 50 Dr. Kanda Runapongsa, Khon Kaen University 25

26 Other Web Services Standards Component Model WSIA (Web Services for Interactive Application) Portal WSRP (Web Services for Remote Portals) Security XML Signature, XML Encryption, XKMS, XACML, SAML, Liberty, WS-Security Security Transaction BTP, WS-Transaction 51 Outline What is Web Services? Why Web Services? Where is Web Services? Web Services Architecture and Standards Web Services Implementation and Tools 52 Dr. Kanda Runapongsa, Khon Kaen University 26

27 Implementing Web Services Web Services enable new kinds of applications, but they do not constitute these applications, nor do they build these applications It is still necessary to use a programming language to design the client and server pieces of the communication Java, C/ C++, C#, ASP, VB, PHP, etc. Web services merely serve as the glue between the client and server applications Client App SOAP or XML- RPC W eb Service Server App 53 Web Services Vendors Microsoft.NET Microsoft s s new computing platform for building, deploying, and running Web Services IBM WebSphere Studio Provide artifacts such as server-side side and client-side deployment descriptions Sun ONE Integrateable able platform as opposed to.net being integrated and proprietary MindElectric Glue A free SOAP framework designed to speed time to market for developing web service components Instantly publish any Java object as a web service Apache Group Axis, SOAP Open source SOAP implementations 54 Dr. Kanda Runapongsa, Khon Kaen University 27

28 .N ET Platform.NET is Microsoft s s new computing platform for building, deploying, and running Web Services The framework consists of three main components The Common Language Runtime (CLR) provides a code execution and code management environment that operates on bytecodes conforming to the Internal Language format (IL).NET framework class library hierarchical, object- oriented, collection of classes ASP.NET componentized version of ASP All of this is integrated into Visual Studio.NET, providing a familiar GUI environment 55.N ET Web Services.NET is Microsoft s s attempt to create a RAD framework for distributed Web Services developers can write.net components in C++, C#, Visual Basic, Jscript, J#, or ASP tools can generate code in C# or Visual Basic class libraries abstract the details of the underlying specifications and protocols (SOAP, XML, WSDL, UDDI) CLR managed services allow developers to focus on developing service logic rather than lower level services (exception handling, security, garbage collecting, etc.) 56 Dr. Kanda Runapongsa, Khon Kaen University 28

29 Java and Web Services Web Services are built on industry specifications with the following goals: language and vendor independent facilitate collaboration between applications as well as information exchange The Java platform is also built on industry specifications and has similar goals: platform independency ( ( Write Once Run Anywhere? ) vendor neutrality extensibility, integration, and simplified connectivity As a vendor-neutral, neutral, platform-independent language, Java is perfect for implementing web service applications 57.NET or J2EE?.NET Allows the use of multiple programming languages Delivers a lot of easy to assemble out-of of-the-box functionality Provides a familiar GUI environment Provides a familiar GUI environment Restricted to MS Windows platform for the foreseeable future Developers are limited in terms of system design and data exchange models J2EE Cross-platform and cross-vendor Provides a wealth of choices for IDE s, application servers, XML parsers, SOAP engines, messaging platforms, etc. Allows developer flexibility in terms of design and data exchange models Development of Web Services is often complex Development is restricted to Java language or CORBA Flexibility can be overwhelming 58 Dr. Kanda Runapongsa, Khon Kaen University 29

30 Java APIs for Web Services SOAP Messaging JAXM (JSR 67), SAAJ, JAX-RPC (JSR 101), JMS WSDL Java API for WSDL (JSR 110) JAX-RPC (JSR 101) UDDI JAXR (JSR 67) 59 Java APIs for ebxml ebxml Message Service (TR&P) JAXM (JSR 67) with ebxml Message Service profile ebxml Registry/ Repository JAXR (JSR 93) CPP/ CPA Java API for ebxml CPP/ CPA (JSR 157) 60 Dr. Kanda Runapongsa, Khon Kaen University 30

31 J2EE Web Services Framework J2EE 1.4 (JSR 151) Web services for J2EE (JSR 109) JAX-RPC (JSR 101) JAXR Sends SOAP method calls to remote parties over the Internet and receives the results Provides a standard way to access business registries and share information SAAJ EJB Java APIs for XML Document Management JAXP (Java API for XML processing, JSR 05) Assembly language for XML document processing JAXB (Java API for XML data-binding, JSR 31) Higher level language for XML document processing Streaming API for XML (JSR 173) Pull-parsing API based on iterator Gives paring control to programmers 62 Dr. Kanda Runapongsa, Khon Kaen University 31

32 Java APIs for XML Security XML Digital Signature (JSR 105) XML Encryption (JSR 106) XML Trust Service (JSR 104) Secure Assertion Markup Language (SAML, JSR 155) WS-Security Security (JSR 183) 63 More Java APIs for Web Services XML Transactioning API for Java (JSR 156) Java API for OASIS BTP Web Services for J2ME (JSR 172) SOAP messaging for J2ME devices Web Services Metadata for J2EE (JSR 181) Metadata based Web Services 64 Dr. Kanda Runapongsa, Khon Kaen University 32

33 Why J2EE for Web Services Web service is just one of many service delivery channels of J2EE No architecture change is needed Existing J2EE components can be easily exposed as Web services Many benefits of J2EE are preserved for Web services Portability, Scalability, Reliability No single-vendor lock in 65 Where Are We Now? Java APIs for Web Services are being developed very rapidly Tools are available now for exposing existing J2EE components as Web services J2EE community has defined overall framework for Web Services (J2EE 1.4, JSR 109) 66 Dr. Kanda Runapongsa, Khon Kaen University 33

34 Design Goals J2EE Web Services Framework Portability of Web services component Over different vendor platforms Over different operational environments Leveraging existing J2EE programming models for service implementation Easy to program and deploy High-level Java APIs Use existing deployment model 67 J2EE Web Services Framework J2EE 1.4 Umbrella framework for Web Services JSR 109, JAX-RPC, JAXR, EJB 2.1, Servlet 2.4 JAX-RPC Defines client programming model Defines Servlet-based Web services endpoint model 68 Dr. Kanda Runapongsa, Khon Kaen University 34

35 J2EE Web Services Framework EJB 2.1 Defines Stateless Session Bean-based Web services endpoint model Servlet 2.4 Will be aligned with JAX-RPC JSR 109 Defines standard Web services packaging and deployment model 69 Web Services in J2EE Environment A set of endpoints (ports) operating on messages Ports are operating within a container Container provides runtime environment Contract for runtime environment are specified in JAX-RPC, EJB 2.1, JSR 109 Service is described in WSDL documents and published to a registry WSDL specifies a contract between service provider and client 70 Dr. Kanda Runapongsa, Khon Kaen University 35

36 Web Service Component and Container Container vs. Component model Web services components get executed within a container Components are portable (under J2EE 1.4) Web service components Web-tier (Servlet-based endpoint) EJB-tier (Stateless session bean-based based endpoint) 71 Web Services Tools for Java Platform Web Services Tools (Available Now!) Tools that come with reference implementations of Java APIs for Web Services (JAX-RPC, JAX-R) Systinet, Cape Clear, Apache SOAP IDE s s (Now) Sun ONE Studio with SOAP-RPC module from Sun JBuilder from Borland JDeveloper from Oracle WebGain from WebGain 72 Dr. Kanda Runapongsa, Khon Kaen University 36

37 Java Web Services Developer Pack (Java WSDP) Provide a convenient all-in in-one package Geared fro developers Contains JAXP, JAXM, SAAJ, JAX-RPC, JAXR Tomcat JSP Tag Library (JSTL) JSSE (Java Secure Socket Extension) Ant build tool Web application deployment tool Java WSDP Registry Server (UDDI server) Extensive tutorial 73 Summary Web Services Overview Definition Types loosely coupled, coarse-grained, asynchronous modular, self-contained, self-describing published, located, invoked across the web B2B facilitator componentized e-service e 74 Dr. Kanda Runapongsa, Khon Kaen University 37

extensible, integreatable Apache SOAP and Axis open source SOAP Web Services

38 Web Services Industry Summary Microsoft s s.net device integration IBM s s Dynamic e-business e flexibility Sun s s ONE extensible, integreatable Apache SOAP and Axis open source SOAP Web Services provides a new paradigm for program to program communication 75 Dr. Kanda Runapongsa, Khon Kaen University 38

(9A05803) WEB SERVICES (ELECTIVE - III)

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