Over the past several weeks we’ve developed a Web
service from start to finish and learned how to
expose product information. The Web service was developed with the .NET
Framework, and a proxy
class was created to test the functionality.

While developing a custom solution like the proxy class is
an option, many commercial products provide Web service integration, making it
easy to take advantage of the functionality provided by existing Web services.
Let’s take a look at some of these products.

Microsoft embraces the Web services revolution

Microsoft, along with other industry giants like IBM and
Sun, has embraced Web services in its productivity applications as well as
development tools. Web services is actually the
cornerstone of the Microsoft .NET programming model. A good example is Microsoft Office
InfoPath 2003.

You can create a data connection between an InfoPath form
and an external data source such as a Web service. Data connections are used to
query and submit data in an InfoPath form that receives data from a Web
service, or submits part or all of your form to a Web service. In addition,
form elements (such as a ListBox) may use a Web
service as its data source.

Microsoft’s
SharePoint Services technology in Windows Server 2003 provides tight
integration as well. SharePoint provides shared Web space for team members and
core sharing tools and services, such as document management, and shared lists
for contacts, announcements, and tasks. You can use SharePoint sites as the
primary Web portal and productivity space for your team or as an ad-hoc shared
space organized around a particular task, meeting, or document.

Microsoft Office Components for SharePoint Products and
Technologies is an add-on pack included with Microsoft Office 2003. It includes
a data retrieval services adaptor, which is a Web service that returns XML data
from multiple data retrieval services data sources or manipulates data on those
data sources. Data retrieval services are collections of data connectors that
are based on Simple Object Access Protocol
(SOAP) and XML.

The standard Microsoft development environment, Visual
Studio .NET, makes it easy to integrate your own or other Web services into an
application. A Web reference may be added to the project by right-clicking on
the project’s references or via the project drop-down menu. This allows you to
add Web services to a project from the local machine or via a Web address. In
addition, you may also use an online directory (UDDI).

Other products

Microsoft is not alone in embracing Web services. For this
reason, other software products make it easy to use Web services. A small
sample includes products like Lotus Domino (version 7), Oracle, and IBM DB2.

Other development tools or platforms like IBM’s WebSphere,
Macromedia’s ColdFusion, NetBeans,
and IntelliJ allow easy Web service creation and
integration of existing services regardless of the tools used to develop it.
For example, a .NET application may easily utilize a Web service developed with
Java and vice versa. The Web service is a block box to other applications.

Making a service available to the world

The Universal Description,
Discovery and Integration (UDDI) specifications define a registry service
for Web services and for other electronic and non-electronic services. A UDDI
registry service is a Web service that manages information about service
providers, service implementations, and service metadata. Service providers can
use UDDI to advertise the services they offer. Service consumers can use UDDI
to discover services that suit their requirements and to obtain the service
metadata needed to consume those services.

A business may deploy one or more private and/or public UDDI
registries. A private registry permits access to only authorized users. A
public registry does not restrict access to the registry. A business may choose
to deploy multiple registries in order to segregate internal and external
service information. An internal registry supports intranet applications, while
an external registry supports extranet applications. Industry groups may deploy
a UDDI registry to support public or private exchanges.

The Microsoft
UDDI SDK is a collection of UDDI client development components, sample
code, and reference documentation that enables programmers to interact with
UDDI-compliant servers. Using this SDK, software developers can add Web service
registration features to development tools, installation programs, or any other
software that needs to locate and bind with remote Web services.

Which companies are already using Web services?

While the technology continues to gain momentum, there are
many companies already offering Web services. The following list provides a
sampling and contains useful information for developers:

  • Amazon: Access the abundance
    of product information provided on the Amazon.com site.
  • PayPal: Integrate the online
    payment service in your application.
  • UPS:
    Package information via an easy to use interface.
  • eBay:
    eBay’s Web service initiatives continue to evolve, but accessing the
    numerous auctions and other eBay features opens up many possibilities.
  • Barnes
    & Noble    : Access book information via the Barnes & Noble site.
  • Google: Take advantage of the
    Internet’s best search engine.

This is only a subset; a Web search will reveal many more
companies that use Web services. In addition, there are numerous third-party
products available to make it easier to utilize these services. For instance,
the eShip
Web Service from Aivea makes it easy to include
shipping charges/information in an e-commerce application.

A world of possibilities

Web services provide a new application development paradigm.
It is another way to handle disconnected systems, so services may be developed
independently and combined to create solutions as necessary. Also, it’s possible
for you to alter the service implementation without affecting the systems that
utilize it. For example, our simple Web service provides product information
via easy-to-use method calls. You can change and redeploy the service code
without user knowledge (unless existing functionality is altered).

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