Sharing makes sense for your organisation and its customers and web
services can deliver information online toend-users and to
disparate systems. Danny Bradbury reports.
For an industry that prides itself on innovation, IT has a poor
track record for solving the problem of data integration. We are
better off now than we were in the early 1980s, when hardware and
operating systems were designed not to talk to rival suppliers'
systems, but connecting applications is still far from intuitive.
Web services is the latest computing model which is supposed to
change all of that.
The term web services, for some users, still means nothing more
than providing online applications, but this misses the point. It
is a distinct technology concept built using technology standards
that were ratified over the last few years. Ignoring it now could
be seriously expensive in the future.
Web services need not operate over the World Wide Web at all.
Whereas the web focuses on providing readable information and
services to customers and employees alike via a browser, web
services aim to make this data available to other applications, in
a standard format. This may be done over the web, or via other
mechanisms such as e-mail.
XML was designed to solve the problem of software applications not
understanding the information that humans can read on the web.
Developed as a way of building languages to represent any type of
information, XML is used to create languages to exchange
application-specific information, such as shipping data or legal
documents.
A web service is an XML-based data feed produced by a software
application that can be read by other applications. For example, a
bank could provide trading system data as a web service for
investors using desktop applications, or a distribution company
could expose its stock database as a web service so that a
retailer's applications could read and analyse the data directly,
rather than an employee re-keying that information into the retail
systems.
This focus on data exchange has defined the initial goal of web
services: integration. "The original argument was to make systems
work better together," says Rob Hailstone, software infrastructure
research director at market research firm IDC. "It was driven by
the recognition that to be a supplier in tomorrow's market you had
to make your systems work with your competitors' systems."
Before web services appeared, enterprise application integration
was supposed to solve the data integration problem, but the systems
were expensive. Some systems were designed in a hub-and-spoke
architecture under which legacy applications would feed their data
into a central system using adapters to translate it into formats
suitable for other applications.
Laurent Seraphin, product director at software tools developer
Borland, says web services are geared to a more point-to-point
integration model, in which XML-enabled applications talk to each
other directly using standard data protocols. Theoretically, this
would have the advantage of making applications more
scalable.
The promise of web services, says Hailstone, is that they create
the opportunity for cross-company application integration, merging
supply chains and making it possible for organisations to work
together more flexibly.
Nevertheless, there are some potential problems with web services
that should not be underestimated. First, says Alan Wilson, a
research analyst at analyst firm Butler Group, cross-company
integration is not yet possible in many cases because users have
not established the necessary processes. "There have been lots of
hiccups. People don't yet know what they are doing internally," he
says.
Second, the fundamental web services protocols that have been
established are inadequate to support robust business transactions,
says Hailstone. "When you get into practical implementations you
get all the security and digital rights issues and the other extra
things that people need to do, such as process management," he
says.
The standards governing this part of the web services story are
still being ratified in many cases, and user organisations will
remain cautious until these protocols have been nailed down. But
despite their immaturity, web services should not be ignored. Apart
from the benefits already addressed, you could expose one of your
core competences and sell it to business customers or consumers.
Eric Austvold, an analyst at US-based analysis firm AMR Research,
advises organisations to test web services technology early but
avoid promising unrealistic business results while web services
remain relatively unproven. Initial use of the technologies should
be in point-to-point integration of applications in a secured
private network, he says.
Many users may prefer to stick with existing legacy integration
products that work effectively. However, when planning integration
with internal and external applications in the future, this
technology will become increasingly important. Building a strategy
to evaluate it now will prepare you for its possible adoption when
it matures.
The terms explained
eXtensible Markup Language
XML, defined by the World Wide Web Consortium, was an offshoot of
the more complex SGML standard. It is a meta-language designed to
create other languages that can describe business-specific
data
Simple Object Access Protocol
Soap is an XML-based language designed to encode web service
requests. It can be transported via http (the transport protocol
used by web applications) or by other mechanisms such as
e-mail
Service-oriented architectures
Because web services use standard protocols, they can be loosely
coupled, so in theory they can be strung together in an ad-hoc way
without extra coding taking place. Such collections of web
services, marshalled together in a flexible way to create
applications, are termed SOAs
Universal Description, Discovery and
Integration
UDDI is a directory standard that lets suppliers list their details
and the web services that they offer. These directories can be used
internally and on the internet to allow users to browse for web
services that fulfil their needs
Web Services Description Language
WSDL is an XML data format designed to describe the details about a
web service and what it is capable of. It is intended for use with
a UDDI directory
Web Services Interoperability
WS-I is a consortium of companies which creates standard guidelines
for the use of web services. It produces best-practice scenarios
for using web services and testing tools to ensure that they work
together effectively.