Web Services Part 1 Service-Oriented Architecture Overview ITEC

Web Services (Part 1) Service-Oriented Architecture Overview ITEC 625 Web Development Fall 2006 Reference: Web Services and Service-Oriented Architectures (The Savvy Manager’s Guide, Chapters 1 -3), Douglas K. Barry, Morgan Kaufmann, 2003

Basic Definitions l l l Web Services are the technologies that allow for making connections. Services are connected together using Web Services, the endpoint of a connection with an underlying computer system that supports the connection. Service-oriented architectures are made up from the combination of services (internal and external); the architecture of composite applications.

Expected Benefits from Web Services and Service-Oriented Architectures (Is it all hype? ) l l Expanded Information Technology options More flexible and responsive IT systems Reduced development time Reduced maintenance costs

The Story of a Business Trip (in the not-too-distant future) l l l l l Air travel, reservations, modifications Car rental, maps, directions Visiting customers Trip planning Calendar synchronization Customer notes Office communications Handheld device interaction Elmo graphic, p. 10.

Customer Contact Information (from External CRM Service) l l Ease of moving between CRM products due to online repository. Standardization of types of messages and data exchanges with the CRM systems. Assumption: Industry consortia able to develop the standards. Data transfers are via XML.

Online Calendar Services l l l l Traveler, spouse, manager, customer Each calendar potentially maintained by a different online service. User establishes rules for data. Software agent enforces the rules which can be used to monitor and report changes. Communication with other agents: travel, airline, hotel software agents. Standardization of data interchanges is critical. Auto retrieval from the online repository.

Updates to Customers/Clients l l Rules for notification of changes Automatic notification Via cell phone or text messaging for example. No more manual logging in to check if there are changes.

Travel Agency Service l l An external service Entirely automated • • • Based on user profile Preferred airline seating, rental car with GPS, preferred hotels, Containing rules for calendar updates • • • Handling of emails, notification of any schedule changes. Dinner changes, time changes Coordination with car rental for GPS rental. Priority customer information (e. g. , visits) sent to Travel Agency for scheduling. Interaction with other software agents

Other Services l l l Car Rental Service • • Receipt of updated itinerary Programming into GPS • Checking status of flights from handheld • • • Relatively easy to swap out one service provider for another. Services may be seen as commodities. Competition will result along lines of cost and innovation. Airlines and Hotel As always, standardization is key.

Analogies of Service-Oriented Architectures and Web Services l l l AV systems have parallels between component structure (s-o architecture) and connection paths (web services). Industry will define standard capabilities of CRM, ERP, other services which will become like commodities. Connections via Web Services using XML • Continued compatibility with EDI, CORBA, DCOM Future trends? Fewer organizations writing software, more buying software. Elmo graphic, p. 20.

Noteworthy Comments… l l Use of service-oriented architectures • Organizations of any size can use them. • • • No cost Fee-for-use basis Monthly fees Blurring of internal/external services • • Easily interchanged Vendors will compete on basis of features and innovations that are independent of connections. • • • User interfaces, automated software agents, rule-based systems, user profiles for customized interactions. Internal development will be difficult. Switching external services will become easy, if not satisfied with results.

The Basics of Web Services l l l Web Services Description Language (WSDL) Universal Description, Discovery, and Integration (UDDI) Simple Object Access Protocol (SOAP) XML Tagged message formats (rather than fixed record formats) Options besides XML Security and Authorization

Web Services Description Language (WSDL) l l l Forms the foundation for Web Services Service Providers first: • • Describe service using WSDL. Publish this definition to a directory of services which could use UDDI or other. Service Consumers then: • • • Issues query(s) to the directory to locate a service Receive details on requests and responses and how to communicate with that service. Send XML service request to provider using the WSDL Service Providers send XML service response based on WSDL back to the consumer. Elmo graphic, p. 23.

Universal Description, Discovery, and Integration (UDDI) l Search of UDDI registry is intended as means of discovering Web Services using WSDL • Contact information and • Web Services available for various organizations. l UDDI registry is also a way to keep up-to -date on the Web Services an organization currently uses.

Simple Object Access Protocol (SOAP) (no longer an acronym) l l Used to send all messages between directories, providers, and consumers. Generally uses HTTP for connections. This will help drive the adoption of Web Services. Elmo graphic, p. 25. • Customer. Info. Request • Customer. Info. Response

Using XML with WSDL l l l l Tagged message format Elmo graphic, p. 26. Data retrieved is not dependent upon the order of the tagged information. Unexpected or additional elements pose no problem (e. g. , in case of updated directory information) Elmo graphics, p. 27, 29, 30, 31, 32 Messages are much longer using XML Options besides XML • • E. g. , for performance reasons Provider/consumer must agree on formats, if not XML.

Security and Authorization l l Often the reason given for not using Web Services. Many topics being worked at OASIS and W 3 C • XML-based • Access, rights of resources, secure encoding, • • service provisioning Assertions, authentication, authorization Signatures, encryption, key management

Options besides XML l Both provider and consumer must agree on the message formats, if not XML.