Overview of Web Services

1
Overview of Web Services
ECE1770 Expert Topic Assignment

• Fan Chen
• Alvin Mok

2
Outline

• What are Web Services How Web Services Emerge
• Web Services ArchitectureOperations
• Web Services Core Protocols
• Some Issues
• Web Services and other Middleware Platforms
• Introduction to Microsoft .NET

3
What are Web Services?

• Web Services are evolving, middleware platform
  that facilitate program-to-program interactions.
• A service is a software entity that can be
  discovered and invoked by other software systems.
• Definition from standardization body W3C
• A Web service is a software system identified by
  a URI, whose public interfaces and bindings are
  defined and described using XML. Its definition
  can be discovered by other software systems.These
  systems may then interact with the Web service in
  a manner prescribed by its definition, using XML
  based messages conveyed by internet protocols

4
How Web Services Emerge

• Web-based Applications Exploiting
• E-Business Urging the program-to-program
  interactions and and integration across
  heterogeneous platforms
• It came to the market at the time when demand for
  such technology was growing rapidly
• The existing middleware technologies were not
  implemented with the Web in mind
• It is backed by many key organizations (both
  commercial and non-commercial)

5
Web Services Standardization Bodies

• W3CWorld Wide Web Consortium
• the most notable web organization founded in
  1994 by the inventor of the web
• Web Architecture, Document formats, interaction,
  etc
• OASIS Organization of Structured Information
  Standards
• Drives the development, convergence and adoption
  of e-business standards
• Service register and publish, Security,
  Transaction,etc
• WS-I Web Services Interoperation Organization
• Initiated by IBM, Microsoft and other vendors
• Articulate/promote a common Web Services vision
• Integrate specifications from various standards
  bodies

6
Web Services Basic Architecture

• Web services are consistent with established
  Service-Oriented Architecture(SOA) principles.
• Web Services Component
• Service
• Service Description
• Web services Roles
• Service providers.
• Service brokers
• Service requestors.
• Web Services Operations
• Publish
• Find
• Interact

7
The Conceptual Web Service Stacks

• Format XML,Extensible Markup Language, to define
  structures of documents

• Search and Find UDDI
• Universal Discovery Description and Integration,
  for registries of Web services
• Description WSDL
• Web Services Description Language, to describe
  networked XML-based services
• Messaging SOAP
• Simple Object Access Protocol, to define a
  uniform way of passing XML-encoded data.
• Transport Internet Protocol,HTTP, STMP, etc.

8
Operations and Message Flow
9
Some Issues

• Technology Areas to be Standardized
• Security Inter-enterprise communications secure
  (XKMS, XACML,etc)
• Business Process Management (WSFL)
• Quality of Service and Reliable Messaging
• SystemNetwork Management
• Chaos There are tons of proposals from vendors
  but none of them has been universally accepted.
• Different implementation for core protocols
  Commercial and open-source toolkits vary widely.
• A long way to go before web services cover the
  full range of requirements for e-business!

10
Web Services and Other Middleware Platforms-A
Vision or Over-simplification?-
No one-size-fits-all solution!
11
Applicability-Examples
Web Interface Web Services
Secure Architecture with Firewall Web Services
Legacy Component( other CORBA EJB) CORBA
Mobile Environment/Thin Client Web Services
Performance CORBA
12
Web Services and CORBA-A Possible Integration
Scenario-

• SOAP request Generated
• Gateway maps WSDL to IDL, builds COBRA request
  and send to the server
• SOAP response is build out of the COBRA response

13
Web Services and Java

• Java community sees XML as complementary
• Java for algorithms, communications
• XML as a universal data interchange format
• Java API for XMLJAXP, JAX-RPC, JAXM, JAXR
• J2EE Web Services Developer Pack
• Only for interoperation outside Java world
• JMS, RMI, RMI/IIOP between Java applications

14
-Thank You-