Dave Elliman

1
A Web Service Client

• Dave Elliman

2
Web services

• Describe themselves using WSDL
• XML Web Service Description Language
• This means there are tools available to produce
  proxies/skeletons/stubs
• For .net we have the command wsdl
• For Java (in JEE) there is wsdl2java

3
For example

• http//www.xmlme.com/WSShakespeare.asmx
• Add ?wsdl to see the xml definition
• Add ?wsdl to see the xml definition
• We can build a client to access this
• wsdl http//www.xmlme.com/WSShakespeare.asmx?wsdl
  
• This produced a C file Shakespeare.cs which
  contains everything needed to access the web
  service
• I then created a C console application in VS2005

4
Hello World
using System using System.Collections.Generic us
ing System.Text namespace speare class
Program static void Main(string
args) Console.Out.WriteLine(
"Hello World")
5
To include the proxy

• I added Shakespeare.cs to the project
• I needed to add a reference System.Web.Services

6
I called the proxy methods
using System using System.Collections.Generic us
ing System.Text class Program static
void Main(string args) String
phrase, speech Shakespeare
shakespeare new Shakespeare() for
( ) phrase
Console.ReadLine() if
(phrase.Equals("quit")) break
String result shakespeare.GetSpeech(phrase)
Console.Out.WriteLine(result)

7
Reflections on that

• It was very easy!
• It was a synchronous method call (RPC)
• In fact it used xml/SOAP
• It was not especially fast in execution
• The client was arbitrary
• Could have been in a web page (ASP.NET)
• Could have been Windows Forms
• Could have been WPF
• Could have been Silverlight

8
Important Lessons

• A Web Service leaves the choice of client open
• Code to connect is easily generated by tools
• Could have used Java tools and JavaFX / Swing as
  easily as .Net clients