Accessing a web service

In its simplest form, an access to a web service is like a function call. Instead of the function call referencing a library on your computer, it references remote functionality over the Internet.

One feature of web services is that they are self-describing. A person who makes a web service available also publishes a description of the API to the web service as a Web Services Description Language (WSDL) file.

A WSDL file is an XML-formatted document that includes information about the web service, including the following information:

  • Operations that you can call on the web service

  • Input parameters that you pass to each operation

  • Return values from an operation

Consuming web services typically is a two-step process:

  1. Parse the WSDL file of the web service to determine its interface.

    A web service makes its associated WSDL file available over the Internet. You must know the URL of the WSDL file defining the service. For example, you can access the WSDL file for the TemperatureService web service at the following URL:

    www.xmethods.net/sd/2001/TemperatureService.wsdl

    For an overview of WSDL syntax, see Working with WSDL files.

  2. Make a request to the web service.

    The following example runs an operation on the Temperature web service to retrieve the temperature in ZIP code 55987: 

    <cfinvoke  
     webservice="http://www.xmethods.net/sd/2001/TemperatureService.wsdl" 
     method="getTemp" 
     returnvariable="aTemp"> 
       <cfinvokeargument name="zipcode" value="55987"/> 
</cfinvoke> 
<cfoutput>The temperature at ZIP code 55987 is #aTemp#</cfoutput>

For more information on consuming web services, see Consuming web services.