Developing Web Services: SunONE vs .NET

1. Developing Web Services: SunONE vs .NET Abner Mendoza mendoza@microagecs.com Selen Ustun selen@cs.tamu.edu

2. What is a Web Service? “A collection of functions that are packaged as a single entity and published to the network for use by other programs. Web Services are building blocks for creating open distributed systems, and allow companies and individuals to quickly and cheaply make their digital assets available worldwide." Graham Glass, CEO and Chief Architect of The Mind Electric

3. So, a Web Service is: • A self-describing software that can • discover and engage other Web Services or applications to complete tasks over the network, and • dynamically locate and interact with other components on the network, to provide a service, without intervention.

4. Technical Motivations for Web Services Technologists are looking for the simplicity and flexibilitypromised, but never delivered, by RPC architectures and object-oriented technologies.

5. Why not CORBA or DCOM? • DCOM is expressly a Microsoft-only architecture. • Although CORBA is intended to provide cross-platform interoperability, in reality it is too complex and semantically ambiguous to provide any level of interoperability without a large amount of manual integration work. • The specter of marshalling executable code and shipping it over the Internet has many security concerns, such as viruses and worms.

6. Why not CORBA or DCOM? • Each of these technologies handles key functionality in its own, propriety way. • CORBA’s payload parameter value format is the Common Data Representation (CDR) format, whereas DCOM uses the incompatible Network Data Representation (NDR) format (Web Services use XML). • CORBA uses Interoperable Object References (IORs) for endpoint naming, whereas DCOM uses OBJREFs (Web Services use URIs, which are generalized URLs).

7. Characteristics of Web Services They are: • described using a service description language • published to a registry of services • discovered through a standard mechanism (at runtime or design time) • invoked through a declared API, usually over a network • composed with other services

8. The Service-Oriented Architecture (SOA) Service Provider Publish Bind Service Registry Service Requester Find

9. Operations of SOA • Service providers publish (and unpublish) their services to a service registry. • Service requesters discover the desired Web Services by searching for their descriptions at the service registry. • Once the requester locates the desired service, its client binds with the service at the service provider and then invokes the service. • SOA is responsible for • describing and organizing the mechanisms and practices for these actions • Describing how Web Services can be combined into larger services.

10. Functional Components of SOA • Service Implementation • Develop a new Web Service and a new service interface • Develop a new Web Service when there is an existing service interface • Develop a new service interface for an existing application • Create a Web Service that wraps an existing application when you have an existing service interface

11. Functional Components of SOA • Publication • Author the Web Service description document. • Written in the Web Services Description Language (WDSL), this document describes what the Web Service will do, where it can be found, and how to invoke it. • Publish the Web Service description document on a Web server so that it is accessible to the desired audience. • Publish the existence of the document in a Web Services registry using the Universal Description, Discovery, and Integration (UDDI) specification.

12. Functional Components of SOA • Discovery • Once a Web Service appears in a registry, any application can discover the service and therefore locate the published Web Service description document. • UDDI registries support pattern queries for automated lookups and return the location of the WSDL file for the desired service. • The location of the file is in the form of a Uniform Resource Indicator (URI), which is a generalization of the Uniform Resource Locator (URL).

13. Functional Components of SOA • Invocation • Author a client using the Simple Object Access Protocol (SOAP). The downloaded WSDL file contains the necessary information for this. Since authoring happens on-the-fly, the Web Service can be invoked dynamically at runtime. • Make a SOAP call. The client then creates a SOAP message describing what it wants the remote Web Service to do and then sends it to the specified URI. Typically, the Web Service returns a SOAP message in the format detailed in the Web Service description document.

14. Architecting Web Services Service Conversations (WSCL) Service Composition (WSFL) UDDI Service Discovery Service Publication Security Management Transactions Quality of Service Service Description (WSDL) Endpoint Description (WSEL) Service Impl. Definition Service Interface Definition Wire Protocol (SOAP) XML Network (HTTP, SMTP, etc)

15. XML • A meta-language for defining the structure and meaning of data. • Aims at solving the problems related to getting computer systems to interact with each other on a programmatic level, by specifying a platform-neutral approach by which objects and programmatic functionality can be operated on a global, distributed basis.

16. ebXML • An XML application to facilitate the sharing of structured business documents. • The ebXML standards support a specific methodology for modeling business requirements and processes. • This makes it possible to define XML semantics for universal descriptions of business services and processes.

17. Simple Object Access Protocol (SOAP) • XML-based messaging and remote procedure call (RPC) specification that enables the exchange of information among distributed systems. • Advantages: • It is an open specification, available for anyone to use. • It is simple to write and is human-readable. • It is extensible, taking advantage of the power of XML to enable loose coupling between systems. • It is a flexible protocol that is useful in both request/response and message passing/queueing architectures. • It can be thought of as a simplified XML-based replacement for IIOP underlying CORBA and DCOM.

18. SOAP Implementations

19. Microsoft SOAP Toolkit • Can be found at http://msdn.Microsoft.com/soap • Requires Visual Basic runtime files, Windows Installer, Internet Explorer 5.0, IIS, and MSXML 3.0 SP1. • Contains: • A client-side component that enables an application to invoke Web Services operations that are described by a WSDL document. • A server side component that maps those operations to COM object method calls. These calls are described by the WSDL and Web Services Meta Language (WSML) files. • Marshalling and unmarshalling components. • A WSDL/WSML document-generator tool.

20. Apache SOAP • Open-source Apache SOAP 2.2 at http://xml.apache.org/soap • Originally developed by IBM, who donated it to the Apache foundation. • Requires: • Java 1.1 or higher, • Apache Jakarta Tomcat 3.2.1 Web server and servlet engine, • Apache Xerses XML parser 1.2.3, • JavaMail (mail.jar), and the JavaBeans Activation Framework.

21. SOAP Interoperability

22. SOAP Interoperability

23. SOAP Interoperability

24. SOAP Interoperability

25. Web Services Description Language (WSDL) • XML-based format for describing Web Services. • Describes: • which operations Web Services can execute, and • the format of the messages Web Services can send and receive. • The WSDL standard is currently at version 1.1 and the official source of the WSDL standard is in a W3C Note, which can be found at http://www.w3c.org/TR/wsdl • Bridges SOAP and UDDI

26. WSDL Implementations • Two most popular implementations are: • The Microsoft SOAP Toolkit – Primarily aimed at developers who want to work with SOAP in a Microsoft environment, although it does support Microsoft’s UDDI implementation. • The IBM Web Services Toolkit (WSTK) – Provides WSDL support, several security enhancements, UDDI integration, and support for the IBM WebSphere application server. Also includes the open-source Web Services Description Language for Java Toolkit (WSDL4J).

27. WSDL the Microsoft Way • WSDL files are generated with SOAP Toolkit. This file is standard WSDL, and it’s generated automatically. • However, Microsoft’s implementation requires another file to map the invoked Web Service operations to COM methods. • This additional file is expressed in the Web Services Markup Language (WSML), which is Microsoft’s propriety language for this particular purpose. • The Microsoft SOAP Toolkit generates WSML files automatically.

28. WSDL the IBM Way • WSTK runs on Linux or Windows 2000/NT 4 • Requires a recent installation of Java Development Kit (JDK). • Can be downloaded from http://www.alphaworks.ibm.com/tech/webservicestoolkit • By separating the service implementation from the service interface, the WSTK allows the service to be changed without affecting the interface. • This provides greater reuse and flexibility.

29. Universal Description, Discovery, and Integration (UDDI) • Platform independent, open framework for describing services, discovering businesses, and integrating business services using the Internet as well as public registries of Web Services designed to store information about businesses and the services they offer. • Is also a specification for building such registries, as well as an application programming interface (API) that exposes the functionality of the registries. • Essentially, it provides for the publication and discovery of Web Services.

30. UDDI Implementations • First two public UDDI registries made available are: • Microsoft’s (http://uddi.microsoft.com) • IBM’s (http://www-3.ibm.com/services/uddi/) • They both support UDDI 2.0 • Both operator sites host production and test registries. • It is possible to interact with both registries from either a Java or a Microsoft (Visual Basic or C#) platform.

31. The Microsoft UDDI SDK • Available at http://www.microsoft.com/downloads/release.asp?ReleaseID=30880 • Requires: • Windows 2000 Professional, Server, or Advanced Server • Visual Studio .NET Beta2 • SQL Server 2000 Desktop Engine (MSDE), Personal, Standard, or Enterprise Edition.

32. UDDI4J (IBM) • Java-based implementation of the UDDI APIs written by IBM and released as open-source. • Its home page is http://oss.software.ibm.com • The package is included in IBM’s Web Services Toolkit (WSTK). • WSTK toolkit is available at http://www.alphaworks.ibm.com/tech/webservicestoolkit

33. Sun Open Net Environment –Sun ONE • The Sun Open Net Environment (Sun ONE) is Sun’s standards-based software vision, architecture, platform, and expertise for building and deploying Web Services. • Web site: http://www.sun.com/sunone • Allows users to build open, Java-based Web Services that are attuned to a user’s location, available networked devices, group affiliation, and current tasks. • It uses J2EE APIs and XML technologies, such as EJBs, JSPs, JNDI, UDDI, ebXML, SOAP, WSDL, JAXP, etc.

34. Sun ONE Framework

35. Sun ONE Framework: The Directory • The iPlanet Directory Server suite of software delivers the software platform necessary to collect, distribute, manage, and protect the most valuable core information assets of an enterprise, such as: • customer, employee, partner, and supplier information, or • non-human entities, such as products, internal resources, and manufacturing equipment capable of providing services

36. Sun ONE Framework: The Portal • The iPlanet Portal Server provides a connection from the user in a particular community to the enterprise. • The iPlanet Portal Server content aggregation capabilities enable the aggregation of any HTML or XML encoded content as well as virtually any application that can be run on any major server OS, such as Microsoft Windows and X Windows-based applications running on the UNIX® operating system.

37. Sun ONE Framework: Application and Integration Servers • The iPlanet Application Server offers two capabilities • It enables access to legacy pieces of the business IT environment. • It provides a scalable platform to run Java technology-based business logic. • The iPlanet Integration Server allows an enterprise to integrate all of its internal services and make them available for use. • Together, they provide an environment for the execution of business logic, integrating of internal legacy application services and external data services.

38. Sun ONE Framework: Development Tools • Forte Tools offer an integrated development environment (IDE) for the Java, C, C++, and FORTRAN languages. • Forte Tools feature automatic loading of the capabilities that the developer needs, which • enables developers of all types to seamlessly access the plug-ins they need • speeds the development of a diversity of Web-based service components.

39. Web Services with J2EE

40. Web Services with J2EE • J2EE Application is hosted within a container, which provides qualities of service necessary for enterprise applications, such as transactions, security, and persistence services. • The business layer performs business processing and data logic. • In large-scale J2EE applications, business logic is built using Enterprise JavaBeans (EJB) components.

41. Web Services with J2EE • It connects to databases using Java Database Connectivity (JDBC) or SQL/J, or existing systems using the Java Connector Architecture (JCA). • It can also connect to business partners using web services technologies (SOAP, UDDI, WSDL, ebXML) through the Java APIs for XML (the JAX APIs).

42. Web Services with J2EE • Business partners can connect with J2EE applications through web services technologies (SOAP, UDDI, WSDL, ebXML). • A servlet, which is a request/response oriented Java object, can accept web service requests from business partners. The servlet uses the JAX APIs to perform web services operations.

43. Web Services with J2EE • Traditional 'thick' clients such as applets or applications connect directly to the EJB layer through the Internet Inter-ORB Protocol (IIOP) rather than web services, since generally the thick clients are written by the same organization that authored J2EE application, and therefore there is no need for XML-based web service collaboration.

44. Web Services with J2EE • Web browsers and wireless devices connect to JavaServer Pages (JSPs) which render user interfaces in HTML, XHTML, or WML.

45. Microsoft .NET Framework • Microsoft builds its Web Services using its new ASP.NET. • ASP.NET extends ASP by providing support for using any .NET programming language, use of existing components, better support for using XML to separate content from formatting and presentation, and compiled code.

46. Web Services with .NET

47. Web Services with .NET • The .NET application is hosted within a container, which provides qualities of service necessary for enterprise applications, such as transactions, security, and messaging services. • The business layer of the .NET application is built using .NET managed components.

48. Web Services with .NET • This layer performs business processing and data logic. It connects to databases using Active Data Objects (ADO.NET) and existing systems using services provided by Microsoft Host Integration Server 2000, such as the COM Transaction Integrator (COM TI). • It can also connect to business partners using web services technologies (SOAP, UDDI, WSDL).

49. Web Services with .NET • Business partners can connect with the .NET application through web services technologies (SOAP, UDDI, WSDL, BizTalk).

50. Web Services with .NET • Traditional 'thick' clients, web browsers, wireless devices connect to Active Server Pages (ASP.NET) which render user interfaces in HTML, XHTML, or WML. • Heavyweight user interfaces are built using Windows Forms.