• www.xmethods.net is a website that lists a large number of Web Services. But this list is not ordered in a way that makes it easy to find a Web Service.
• UDDI is an initative that aims to make it easier to locate Web Services.
• UDDI means Universal Description, Discovery and Integration.
• UDDI is targetted at two kinds of customers: those businesses who want to publish what services they offer and those businesses who need to locate a service and access it from some program.
• More details about UDDI can be obtained at http://www.uddi.org/.
• If you go to http://www.xmethods.net/, you will get a WWW page listing the 30 WWW Services most recently added to this website.
• However, half way down this WWW page, there is a link labelled FULL LIST.
• If you click on this link, you will get the full list of Web Services known to www.xmethods.net.
• Towards the bottom of the full list, there is a Web Service described as:

  0514: Publisher:       dpchiesa 
  0515: Service Name:    ZipToCityState 
  0516: Description:     Retrieves valid City+State pairs for a given 
  0517:                  US Zip Code, or longitude/latitude for a zipcode. 
  0518:                  Also retrieves zipcodes for city/state pairs
  0519: Implementation:  MS .NET
  

• If you click on the ZipToCityState link, you will get more details about this Web Service.
• In particular, it says that a WSDL document is available at:

  http://www.winisp.net/cheeso/zips/ZipService.asmx?WSDL
  

The above URL ends in .asmx?WSDL. The .asmx is a sure sign that this Web Service has been implemented using Microsoft's .NET Framework. As explained earlier, one of the benefits of using .NET for Web Services is that WWW pages that can be used to test a Web Service are dynamically generated. You can go to the first of these WWW pages by using the above URL without the last 5 characters, i.e., by going to:
http://www.winisp.net/cheeso/zips/ZipService.asmx

You should get a WWW page saying:

0520: The following operations are supported. For a formal definition, 
0521: please review the Service Description.
0522:    * ZipToLatLong
0523:    * CityToZip
0524:    * ZipToCityAndState
0525:    * CityTo1Zip
0526:    * ZipTo1CityAndState

This is a list of the names of the methods provided by the Web Service. If you now click on one of these names, e.g., ZipTo1CityAndState, another WWW page is dynamically generated. It is the WWW page at:
http://www.winisp.net/cheeso/zips/ZipService.asmx?op=ZipTo1CityAndState
This WWW page provides a textbox and an Invoke button.

If you type a zipcode like 94042 into the textbox and click on the Invoke button, the browser will contact the webserver at www.winisp.net to get it to execute the ZipTo1CityAndState method. After a little time, your browser will give you the following WWW page:

0527: <?xml version="1.0" encoding="utf-8"?>
0528: <string xmlns="http://dinoch.dyndns.org/webservices/">
0529: MOUNTAIN VIEW CA
0530: </string> 

You may have to click on View Page Source to see this XML.

You could use the techniques described in Section 4 of this document to provide a program that accesses this Web Service.