1. WEB SERVICES AN EVALUATION OF MODERN WEB SERVICE ARCHITECTURES Gordon Hew COMS E6125 Web Information Management Systems

2. Agenda  Introduction  Architectural Styles  Remote Procedure Call (RPC)  Serviced Oriented Architecture (SOA)  Representational State Transfer (REST)  Conclusion

3. Web Services & Architectural Styles  What are Web Services?  Why are they important?  What are some examples?  Why are Architectural Styles important?  What criteria will be using to evaluate these styles?

4. Remote Procedure Call (RPC)  RPC  Client invocation of a local representation of a remote method

5. Remote Procedure Call (RPC)  Example Technologies  XML-RPC  RPC Style SOAP  Advantages  Simple  Disadvantages  Tightly Coupled  Not Easily Scalable

6. Service Oriented Architecture (SOA)  SOA Principles  Separation of concerns  Service Orientation Loosely Coupled Formal Contracts Abstract Logic Composable Reusable Autonomous Stateless Discoverable

7. Service Oriented Architecture (SOA)  SOA Workflow

8. Service Oriented Architecture (SOA)  Primary Technologies  Document-centric SOAP  WSDL  UDDI  Advantages  Extensible  Scalable  Disadvantages  Excessive Configuration  Reliance on Tools

9. Representational State Transfer (REST)  REST Principles  Resource Oriented  Uniquely Addressable  Client-Server  Stateless  Cache  Uniform Interface  Layered System

10. Representational State Transfer (REST)  REST Workflow

11. Representational State Transfer (REST)  Example Framework  Restlet  Advantages  Extensible  Scalable  Content Types  Disadvantages  Data Size

12. Conclusion  REST is the best overall architecture style  Not too complex  Extensible  Interoperable  Scalable  Challenges to Adoption  Benefits are not immediately recognizable  Maturity  Investment in SOA

13. References  Carr, David F. "Will Enterprise Architects Get Any REST in 2008?" Baseline. 20 Dec. 2007. 10 Mar. 2008.  Erl, Thomas. "Exclusive SOA Web Services Journal Briefing – Thomas Erl on SOA." SOA World Magazine. 29 Oct. 2005. 01 Mar. 2008.  Felding, Roy T. Architectural Styles and the Design of Network-Based Software Architectures. Diss. Univ. of California, Irvine, 2000. 2 Feb 2008.  Gisolfi, Dan. "Web Services Architect, Part 3: is Web Services the Reincarnation of CORBA?" IBM DeveloperWorks. 01 July 2001. IBM. 13 Mar. 2008.  Mahmoud, Qusay H. "Service-Oriented Architecture (SOA) and Web Services: the Road to Enterprise Application Integration (EAI)." Sun Developer Network. Apr. 2005. 01 Mar. 2008.  Melgar, David. "Message-Centric Web Services Vs RPC-Style Invocations." SOA World Magazine. Mar. 2003. 08 Mar. 2008.  Peltz, Chris. "Applying Design Issues and Patterns in Web Services." DevX. 7 Jan. 2003. 08 Mar. 2008.  Richardson, Leonard, and Sam Ruby. RESTful Web Services. O'Reilly Media, Inc., 2007.  Vinoski, Steve. "Demystifying RESTful Data Coupling." Mar.-Apr. 2008. IEE. 01 Mar. 2008.  Vinoski, Steve. "REST Eye for the SOA Guy." IEEE Internet Computing 11 (2007): 82-84. 10 Mar. 2008.  Leventhal, Michael, and Zhang Sen. "True XML Web Services." XML Europe 2003 (2003). 13 Mar. 2008.