1. WEB SERVICES
DAVIDE ZERBINO

2. Summary: Introduction Definition Web Service Model
Web Service Architecture
Web Service in action
Advantages
Web Service Development Lifecycle
Tools
References

3. Introduction
A Software Service is a something that accepts digital requests and returns digital responses e.g. C function, a Java Object
A computer application can be thought of as a well-orchestrated set of services
Web Services are a new breed of software component that is a language, platform, and location indipendent
Is accessible over the web
Web services are an abbrevation for Web of Services
Distributed applications will be assembled from a web of software services

4. Web Service
Is registred and can be located through a Web service registry.
Communicate using XML message over standard Web protocols.
Support loosely-coupled connections between systems.

5. Definition of Web Service
“A Web service is an interface that describes a collection of operations that are network-accessibile through standardized XML messaging.”
Heather Kreger
IBM Software Group

6. The Web Services Model
The Web service architecture is based upon the interactions between three roles:
Service
Registry
application that is looking for and invoking an interaction with a service
owner of the services
searchable registry where service provider publish
their service descriptions and where service find service
Service registry
Service
Requestor
Service
Provider

7. The Web Services Model Others element are: Service Description Service
Registry
Requestor
Provider
Service registry
Service

8. The Web Services Model Others element are:
Description
Contains details of the interface and
implementation of the service
Service registry
It is a software module deployed on the
network-accessible platforms provided by
the service provider

9. The Web Services Model
The interactions involve the publish, find and bind operation
Service
Registry
Requestor
Provider
Find
Publish
Service registry
Bind

10. The Web Service Stack Security Management Quality of services
HTTP, FTP, , MQ, etc
SOAP
WSDL
UDDI
WSFL
Standard Tecnologies
Requirements
Network
Service Description
XML-Based Messaging
Service publication
Service Discovery
Service Flow

11. Web services must be network-accessible
The Network
Web services must be network-accessible
For its ubiquity
HTTP is the standard network protocol for internet-available Web Services
Others network protocols are SMTP, FTP and for intranet domain: MQSeries, CORBA

12. XML-based Messaging
Represent the use of XML as the basis for the messaging protocol
The current industry standard for XML messaging is SOAP
IBM, Microsoft, Sun and others submitted SOAP to the W3C
SOAP (Simple Object Access Protocol)
Is a simple and lightweight XML-based mechanism for exchanging structured data beetween network applications

13. SOAP Lightweight communication protocol
For communication between applications one-way, request/response, multicast, etc..
Designed to communicate via HTTP
Not tied to any component technology
Not tied to any programming language
Based on XML
Simple and extensible

14. SOAP SOAP consists of three parts:
An envelope that defines a framework for describing what is in a message
A set of encoding rules for expressing istances of application-defined data types
A convention for representing remote procedure calls and responses

15. SOAP 1 4 3 2 web service Application SOAP Network protocol
Request/Response 1 4 3 2

16. Service Description: From XML to Web services
Service provider comunicates all the specifications through service description
The service description combined with SOAP infrastructure hides details as platform, programming language from the service requestror’s application and the service provider’s Web Service
Web service uses WSDL for base-level service description

17. WSDL WSDL: Web Service Definition Language
is an XML-based language used to define Web Services and describe how to access them
Industry standard W3C
Service
Implementation
Definition
Interface
Service
Port
Binding
PortType
Message
Type

18. Discovery and Publication: UDDI
Stands for Universal Description, Discovery and Integration
Defines a way to publish and discover information about web services
Collaboration between Microsoft, IBM, Ariba that resulted in the creation of web service registry
Not standard

19. UDDI
Defines a data structure standard for representing service description information in XML
The core component of the UDDI project is the UDDI business registration, an XML file used to describe a business entity and its Web services

20. UDDI The UDDI Business Registry can be used at a business level
To check whether a given partner has particular Web service interfaces.
To find companies in a given industry with a given type of services.
To locate information about how a partner or intended partner has exposed a Web service in order to learn the technical details required to interact with that service

21. WSFL Overview
Web Service Flow Language (WSFL) is an XML language for the description of Web Services Composition
It is possible to produce web services by composing web services
Intra-enterprise web services might collaborate to present a single Web Service Interface to the public
Web services from different eneterprises might collaborate to perform business to business transactions
Service Flow described how service-to-service communications, collaborations and flows are performed.

22. Web Service in Action: B2B
Customer
Supplier
Credit Bureau
Check validity
Service
Account Service
Warehouse

23. Advantages Interoperability:
Any web services can interact with any other web service
Ubiquity:
Web services communicate using HTTP and XML.
Low Barrier to Entry:
The concepts behind web services are easy to understand and toolkits are frely available from many vendors
Industry Support:
All the major vendor are supporting SOAP and the surrounding web services standards

24. Web Services Development Lifecycle
The development lifecycle can have four phase:
BUILD :
development and testing of the web service implementation
definition of the services interface description
definition of the service implementation description
DEPLOY :
publication of the services interface and service implementation
RUN :
The web service is available for invocation
The web service is fully deployed, operational and network-accessible from the services provider
Now the service requestor can perform the find and bind operations
MANAGE :
Covers ongoing management and administration of the web services application

25. Tools Microsoft SOAP Toolkit 2.0
Microsoft Visual Studio .NET and .NET Framework
Apache SOAP Toolkit and AXIS
IBM Web Services Toolkit
SUN JavaTM 2 Platform, Enterprise Edition (J2EE)

26. Example: Airport Weather Service
Interface:
getLocation()
getWind()
getTemperature()
getSky()
getPressure()
getHumidity()
getSummary()
Airport Weather
More informations:
Web Interface:

27. References About SOAP : http://www.w3c.org/TR/soap About WSDL :
About UDDI :
About WSFL :

28. Other Papers About Web service Architecture:
Web Services Conceptual Architecture (WSCA 1.0) -Heather Kreger - IBM SW Group
About Web service development lifecycle:
Web Services Development Concepts (WSDC 1.0) -Peter Brittenham- IBM SW Group
About Web service model:
Web Services : Building Blocks for Distributed System -Graham Glass -

29. The End

30. Web Server in Action (2/2)
HTTP
WSDL
SOAP
Application
Interoperability

31. XML XML: eXtensible Markup Languages
A version of HTML that allows any kind of data to be represented in a simple and portable way
<giocatore id = 212>
<nome> Davide <\nome>
<cognome> Zerbino <\cognome>
<\giocatore>