Web Services (Part 1) Service-Oriented Architecture Overview

1
Web Services (Part 1)Service-Oriented
Architecture Overview

• ITEC 625 Web Development
• Fall 2006
• Reference
• Web Services and Service-Oriented Architectures
  (The Savvy Managers Guide, Chapters 1-3),
  Douglas K. Barry, Morgan Kaufmann, 2003

2
Basic Definitions

• 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.

3
Expected Benefits fromWeb Services and
Service-Oriented Architectures(Is it all hype?)

• Expanded Information Technology options
• More flexible and responsive IT systems
• Reduced development time
• Reduced maintenance costs

4
The Story of a Business Trip (in the
not-too-distant future)

• 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.

5
Customer Contact Information(from External CRM
Service)

• 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.

6
Online Calendar Services

• 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.

7
Updates to Customers/Clients

• 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.

8
Travel Agency Service

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

9
Other Services

• Car Rental Service
• Receipt of updated itinerary
• Programming into GPS
• Airlines and Hotel
• Checking status of flights from handheld
• As always, standardization is key.
• 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.

10
Analogies ofService-Oriented Architecturesand
Web Services

• 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.

11
Noteworthy Comments

• 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.

12
The Basics of Web Services

• 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

13
Web Services Description Language (WSDL)

• 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.

14
Universal Description, Discovery, and Integration
(UDDI)

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

15
Simple Object Access Protocol (SOAP) (no longer
an acronym)

• 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.
• CustomerInfoRequest
• CustomerInfoResponse

16
Using XML with WSDL

• 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.

17
Security and Authorization

• Often the reason given for not using Web
  Services.
• Many topics being worked at OASIS and W3C
• XML-based
• Access, rights of resources, secure encoding,
  service provisioning
• Assertions, authentication, authorization
• Signatures, encryption, key management

18
Options besides XML

• Both provider and consumer must agree on the
  message formats, if not XML.