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COMS 6125
Web Enhanced Information
Management
Luba Leyzerenok
[email protected]
Web Services technology
and its advantages
for e-business commerce
Introduction: what led to Web
Services?
The World Wide Web was originally designed for
information exchange where humans are the
primary user of the Web.
As World Wide Web was growing into a standard
mechanism for e-commerce, each e-service
exposed its interfaces in an ad-hoc manner, with
no uniform access methods. This led to almost
non-existent interoperability between e-services.
There was a great need for technology that will
provide application to application communication
and, therefore, a machine user.
What is Web Services?
W3C group defines Web Services as “a software
system designed to support interoperable machineto-machine interaction over a network. It has an
interface described in a machine-processable
format (WSDL). Other systems interact with the
Web service in a manner prescribed by its
description using SOAP messages, typically
conveyed using HTTP with an XML serialization
in conjunction with other Web-related standards.
The development of the standard technologies that
are used in building Web services made machineto-machine interaction possible. ”
Web Services benefits
(business perspective)
Web services allow business processes to be made
easily available over the Internet to the external
and internal partners.
The ease of integration allows business to be built
quickly by utilizing vast number of Web services
available on the Internet.
Web services benefits
(technical perspective)
Standard technologies used in building Web
services allow easy integration of different
applications and make machine-to-machine (or
application-to-application) communication not
only possible, but also quick and easy.
Web services provide a mechanism for building
systems that consist of loosely coupled
components that can be composed dynamically.
The web service implementation details, such as
the language in which the web service is
implemented, are irrelevant to an application that
is invoking this web service.
Web Services technology
overview.
Service Provider - The purpose of web service is
to provide users with some functionality on behalf
of its owners. Web service provider implements
the Web Service, describes it and publishes it to
one or more Service Registry.
Service Requestor - Service requestor is a
consumer (human or application) of a web service
who wishes to use some web service. A consumer
utilizes the services of the web service directly by
connecting to the web service and sending SOAP
messages.
Web Services technology
overview. (cont)
Service Registry - The service registry is the
central repository of service available on the
Internet or private (Intranet) network.
Web Services protocol stock
The Web services architecture can also be
considered as a set of its underlying technologies.
It might be useful to think of Web services as a
layered set of technologies.
Web Services protocol stock
(cont)
Discovery
UDDI
Description
WSDL
Messaging
SOAP, XML,
XML-RPC
Transport
HTTP, FTP,
SMTP
Messaging Layer: XML and
SOAP
Web services use XML messages to exchange
information between service requestor and the
service provider.
SOAP is a standard and extensible XML based
protocol for exchanging messages between
applications.
SOAP messages are written entirely in XML, and
therefore they are extensible, platform and
language independent.
Description Layer: WSDL
WSDL is an XML language for describing Web
services.
Web services descriptions are based on the
abstract model of what a particular web service
offers.
Developers use WSDL to describe the webservices details, such as what operations service
provides and what input/outputs are associated
with the given service. Description also includes
what messages are exchanged between the
provider and requestor.
Discovery Layer: UDDI
The discovery process is a process by which the
service requestor finds an appropriate service
provider.
UDDI is the most well known registry
specification. The purpose of the UDDI is to
connect service requestors with service providers.
Service providers use UDDI to advertise their web
services. Service requestors use UDDI to find the
services that fit their needs and they query the
registry either at design time or dynamically at
runtime.
Web Services Advantages
Web services are built using set of open industry
standards, such as XML, SOAP, WSDL and
UDDI, which proved their scalability. Moreover, it
minimizes the possibility of industry domination
by a single vendor.
Language and platform agnostic.
Interoperability and ease of integration.
Dynamic interaction: change of the web services
by one of the partners does not require change by
web service users (given that the API stayed the
same).
Web Services Advantages (cont)
From the business point of view, the Web services
promise the easy and quick integration of
application functionality.
Loose component coupling. This makes it very
easy for developers and business to change
different components if required.
Conclusion
In general, the Web services are most beneficial
when:
The applications must operate over the Internet
where speed and reliability cannot be guaranteed.
There is no ability to control that requestors and
providers are upgraded at once.
When the platform and vendor neutrality is
important.
When an existing application needs to be exposed
for use over a network.