By Johann Dumser, R&D Consultant (jdumser@techmetrix.net)
and
Jean-Christophe Cimetiere, CEO Techmetrix (jcc@techmetrix.com)
Printer Friendly Version
We've made
it - the whole concept of Web Service is taking off. Certain
companies have already taken the plunge and have joined
support and development groups in an effort to standardize Web
Service Description Languages, while others are concentrating
on hosting and referencing primary services. Here's how XML,
SOAP and, more recently, UDDI and WSDL are making this
possible.
Hosting
Web Services and supporting deployment
The XMethods site
is a portal which aims to promote Web Services. To this end,
its three founders offer, free of charge, the possibility of
using or offering Web Services of public interest with the aim
of boosting their creation, deployment and use. Various SOAP
implementations are available; these currently include a Java
implementation, ApacheSOAP, and a Perl implementation, SOAP::Lite.
To be
completely usable with most SOAP implementations, as XMethod
suggests, a Web Service should provide a complete description
which includes the following elements:
- SOAP End point URL: URL where the
SOAP server receives the SOAP request
E.g.:
http://www.server.com/rpcRouter
- SOAPAction: Some services may
demand a SOAPAction Header
E.g.:
urn:xmethodsSoapPing#pingHost
- Method Namespace URI: URI
(Univeral Resource Identifier) of the object for which
the method is called
E.g.:
urn:StockQuoteEngine
- Method Name(s): Name of the
available methods
E.g.: getStockQuote,
getMarketCap
- WSDL URL: URL of a file which
fully describes a service in WSDL format. The WSDL
description is all that is needed to execute the
service.
E.g.:
http://www.server.com/stockquote.wsdl
- Instructions: Instructions for
use of service
- Server Implementation: Writing
environment necessary for interoperability
E.g.:
SOAP::Lite for Perl v0.35
- Sample URL Client Code: Source
code of the downloadable example
E.g.:
http://www.server.com/sampleClient.java
|
The
examples shown on the XMethods site are very varied:
translation using BabelFish Altavista, Verification of Domain
Name, Ping Test, FedEx Package Tracking display of price of
books at Barnes&Nobles.
Each
service uses either the Perl implementation (SOAP::Lite) or
the Java one (ApacheSOAP), but other initiatives have led to
new listed implementations such as 4s4c.
For the
majority of these services the code of the client example is
available and ready for use. You simply need to configure your
station using an appropriate implementation. This rapid and
effective installation enables you to access SOAP services via
a simple process, which consists in invoking a SOAP object
which defines its end point, URI and the method to be called
corresponding to the service requested.
We carried
out interoperability tests between Java and Perl
implementations and these proved conclusive. We will discuss
these aspects in more detail in a later article.
In order
to avoid the security restrictions imposed by certain
companies, XMethods has made all its services available on
port 80 (standard port for HTTP). In addition, XMethods tries
as far as possible to provide the WSDL associated with each
service, as more and more implementations rely on this
description language to call Web Services.
Onto Page II
Printer Friendly Version
TechMetrix Research is a technically
focused analyst firm focused on e-business application development needs.
Based in Boston, Mass., the firm publishes comparison reports and product
reviews designed to aid enterprises with decision making and to keep pace
with the fast-moving e-business market.
TechMetrix is a U.S.-based subsidiary
of SQLI, a European company that offers on-site development services to
international organizations. SQLI specializes in e-business project
development.
Events
[
Home | Discussion Forum | How Do I... |
Lotus Notes Intranets |
Microsoft SharePoint |
Products |
Shopping
]
