Web Services

warrenaldo

Folks,

I did some basic stuff on web services when in college. But its been a while and i cannot remember what this is all about. Im readingthe techis jargon (from google) on the topic but i dont see any real world examples of how its used and what it does?

Can anybody help me undestand.

seamus

"Web Services" is a very vague term.

It really depends on context.

From my POV, a web service is one which allows remote access to it - be that Internet or intranet. Simple as. There are thousands of types of "Web Services".

From someone else's POV, a web service may be a particular type of commerce provided over the internet - e.g. they may see Amazon.com as one type of web service, and hotmail as another type of web service.

It really is a very vague term.

warrenaldo

you have confused me even more - by web services i mean distributed applications. This is the term that keeps on being thrown at me.

Are you saying that amazon is a web service - because its on the web and provides a service? This is not really what i mean?

mathie

A web service is basically just a program that can be accessed over the Interweb

A client usually talks to a web service via XML files (SOAP)

forbairt

warrenaldo wrote:

Are you saying that amazon is a web service - because its on the web and provides a service? This is not really what i mean?

Amazon provides an API that you can build on to sell their products ... (why bother .... cus of the affiliate schemes)

nice1franko

http://en.wikipedia.org/wiki/Web_service

http://www.w3schools.com/soap/default.asp

In it's simplest form, it's a bit like any ould RSS reader.

Say you want to make a little application that tells you the weather forecast. You have a Go btn and when user presses it you make a reqest to the soap server (i.e. "web service" provider) which might look something like (pseudo code):

String x = mySoapBroker.get("http://someweathersite.com/SOAP_SERVER/weatherPlease");

// now var x contians something like <?xml version="1.0" ?><weather>it's fairly pissin</weather> </xml>

Ginger

Do you understand functions?

Well, think of a web service as a function that is defined online and hosted online and the same way you use a function, you use the webservice

So for example you have a webservice that returns the details of a book based on an ISBN code (Amazon does this)

So in the liikes of Visual Studio, you add the web service as a reference, (think of this of using a #include in C), it means that you can create an object of the type of your webservice. When this happens you can use the function that it contains to do what you want.

So example

var myWebService = new AmazonWebService
var myReturnedXML

myReturnedXML = myWebService.GetBookDetailsByISBN(myISBNCode)

Now why use a webservice over a normal function.. Well this is the distributed applications. Imagine every time that amazon changed your system, you had to change yours.. wouldnt be very nice would it. With the web service idea, they present this function name to you and tell you that it requires some inputs and thats all you need to know. They change their code in whatever way they need to, all you care about is that you send in your ISBN code and get back your details.

Also it means that millions of people can use this and not have to write their own. Now distributed applications dont have all their components on the same computer they may not be even on the same network or country. The downside is in the case of the amazon example is that if your application is on your local computer and your internet access is broken or the service itself is offline, your application wont work



Hope this helps somewhat..

warrenaldo

Ginger - thate exactly what i was looking for - thanks to all.

Liam Byrne

Well put, Ginger (where's the smiley for "thumbs up" ??)

Ginger

Ta, I used to teach this stuff so its a case of find something taht people are familiar with and go from there.. its mostly the terms that get people. The idea is quite simple, the terminology can be very confusing alright