Web Services – A Primer Mark Resmer, eCollege Les Smith, SCT UBC, October

Topics of Discussion  The Vision of Web services  Evolution of distributed computing  Definitions of Web services  Applications of Web services  Maturity of standards  Common concerns  Recommendations

The vision “The great promise of Web services is that distributed components will be able to work together seamlessly. Instead of devoting massive resources to system integration, Web services have an automatic way of telling other services how they want to communicate. As a result, entire architectures will be snapped together like a bunch of Lego blocks.“

Web services in context  The last two major defining events in technology were based on simple ubiquitous protocols – not big complex frameworks  The next defining event will follow the same pattern SOAP, WSDL, and UDDI – not DCOM and CORBA Typically, widespread effects lag protocol introduction  Common interfaces into applications regardless of native language Web services work with.NET and J2EE technologies rather than as a competing technology.

Evolution of distributed computing  “Web services technology is not a revolution in the world of computing but an evolution of the old concepts of component-based software development.”  Evolved from prior protocols for distributed computing—such as DCOM, DCE, CORBA and Java RMI Author: Uche Ogbuji 9/28/2002

Timeline of Distributed Computing Author: Uche Ogbuji 9/28/2002

The web services hype cycle

What are web services? Web services are XML interfaces providing data and services to other applications and enabling loosely coupled integration through the Web Web Services expose useful functionality to Web users through a standard Web protocol Web services provide a way to describe their interfaces in enough detail to allow a user to build a client application to talk to them Web services are registered so that potential users can find them easily

Web services building blocks Description Message format Encoding Transport Discovery

Understanding the acronyms SOAP  Simple Object Access Protocol  XML message protocol for web services WSDL  Web Services Description Language  Provides descriptions of SOAP services UDDI  Universal Description, Discovery and Integration  Stores WSDL and other information about web services

How do web services work? Web service requestor UDDI service Web service provider publish Register Web Service (at development time) 1 bind Retrieve WSDL Definition 3 WSDL Document call Call Web Service 4 SOAP service Based on a diagram by Justin Tilton find 2 look up web service

What can you do with them?  Grading in a browser is not ideal Screen refresh issues Limited computation Simple user interface  Grading in Excel would be much better… …but download/upload is inconvenient… …and there’s always the chance that you can mess up the formatting in the off-line copy  The answer – a connected Excel gradebook Template contains call to web service to get list of courses taught by faculty member Selecting a course calls web service that populates spreadsheet with list of assignments and another one to populate student roster Selecting an assignment calls web service to populate table with grades Changing a value calls a web service to update the database Excel gradebook Result – an Excel gradebook that “automagically” populates the Course Management System database

Why are Web Services important?  Revolution in software industry business models The “Third Way” after licensed software distribution and ASPs – potentially combines best features of both  Leveling the playing field Nobody is an industry leader in web services yet Rare opportunity for real innovation  Improved productivity Seamless integration of remote and desktop applications Can utilize public software repositories Less programming effort (cost savings)

Web services – deployment examples Provider Institution HTML DB Internet Browser Current application HTML Excel SOAP Web Service SOAP Browser SOAP HTML Excel MQ Server Yes

The emerging standards stack

H.E. standards groups  PESC – Postsecondary Electronics Standards Council Specifications for transcripts & Financial Aid  IMS Global Learning Consortium Multiple specifications for eLearning  Internet2/Mace – (Shibboleth) Identity Management using SAML  National Student Clearinghouse Web service for verification of enrollment, degree & loan data

Who is working on web services?  Systems vendors Microsoft Oracle IBM Sun BEA and others…  Applications vendors eCollege SCT Blackboard PeopleSoft im+m …and others  Non-profit organizations HEKATE IMS uPortal OKI

What are the big challenges ahead?  Orchestration/choreog raphy Web services are not transactional and provide basic "request/ response" functionality. Requires business rules, security and identity to assure consistency of transactions  Performance lots of message manipulation  Quality of service How to ensure that distributed applications are always available How to develop trust models for remote services  Business models Subscription models – what are the metrics? Pay-as you go models CoOp models …or what?

Recommendations  Participate in standards development activities to stay abreast of developments  Do not wait until everything is finalized. Start now with SOAP and WSDL  Do not let security concerns hold up Web services development … SSL and SAML or WS-Security will suffice for now  Evaluate your vendor’s support of Web services standards  Do not expect Web services to transform your business immediately; first use Web services to transform your processes

Where to find out more       Yes