[thelist] Web services - what's the difference?

Dougal Campbell dougal at gunters.org
Fri Dec 13 10:34:01 CST 2002

On Fri, 13 Dec 2002, Peter-Paul Koch wrote:

> Hi,
> I'm having some trouble understanding the concept of web services.

So is most of the web industry :)

> So currently I'm thinking that the term 'web services' is one more in the
> long string of meaningless market-isms that engulfs the Web. The idea behind
> web services is solid, of course, but there isn't much difference with the
> old situation.

When *I* think of web services, I think in terms of an API, rather than
in terms of a single application. A web service is typically a
well-defined method of remotely calling a function, without having to
worry about the exact implementation of the function. It's most useful
when you have multiple servers that need access to the same set of
functions, and/or when you want to expose some of your information to
the outside world programatically.

For example, I work for a company in the trucking industry. Our
customers want to get tracking information about their shipments
(similar to how you can get your tracking/delivery info from UPS or
FedEx). The tracking information will include things like the addresses
of the shipper and consignee (recipient), the terminal locations that
picked up and delivered the shipment, who signed for it, dates and
times, etc. I can code up a lot of the lookup functions as web services,
because they are generally useful, both internally and externally.

So, I code up an API for functions like "which terminal services this
zip code?", or "return the full address and phone number for the
terminal with termid XYZ", or "return tracking details for tracking ID
nnnnnnnn", "what is the standard delivery time between these two zip
codes?", etc. Not only can *I* use these functions internally to build
tracking information web pages, but our customers can use it to embed
our tracking info into their own web sites.

Why would we want that? Let's say that MY customer is a furniture store,
Foo Furniture. FF uses us as their shipper. John Q. Public goes to Foo,
and buys a houseful of furniture and tells Foo to deliver it to their
home. Foo gives JQP a tracking number, and links it to *our* tracking
number. When JQP checks the Foo website to track the status of their
delivery, the Foo server contacts the web service that we provide, gets
back an XML dataset, parses it out, and presents some results back to
John, who never has to know, or indeed care, that a third party is doing
the delivery, or that the other web site was contacted to get the
tracking info.

Clear as mud?

Ernest MacDougal Campbell III, MCP+I, MCSE <dougal at gunters.org>
http://dougal.gunters.org/             http://spam.gunters.org/
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