Use Dynamic URLs When Referencing Web Services

- J.D. Meier, Jason Taylor, Alex Mackman, Prashant Bansode

If you want to call a Web service, you must first add a Web reference to your project. This generates a proxy class through which you interact with the Web service. The proxy code initially contains a static Uniform Resource Locator (URL) for the Web service; for example, http://localhost or http://SomeWebServer.

Important: For Web services in your current solution that execute on your computer, always use http://localhost rather than http://MyComputerName to ensure that the reference remains valid on all computers.

The static URL that is embedded within the proxy is usually not the URL that you require in either the production or test environment. Typically, the required URL varies as your application moves from development to test to production. You have three options to address this issue:
  • You can programmatically set the Web service URL when you create an instance of the proxy class.
  • A more flexible approach that avoids a hard-coded URL in the proxy is to set the URL Behavior property of the Web service reference to Dynamic. This is the preferred approach. When you set the property to Dynamic, code is added to the proxy class to retrieve the Web service URL from a custom configuration section of the application configuration file—Web.config for a Web application or SomeApp.exe.config for a Windows application.
  • You can also generate the proxy by using the WSDL.exe command-line tool and specifying the /urlkey switch. This works in a similar way to setting the URL Behavior property in that it adds code to the proxy to retrieve the Web service URL, but in this case the URL is stored in the <applicationSettings> section of the application configuration file.

The dynamic URL approach also lets you provide a user configuration file, which can override the main application configuration file. This allows separate developers (and members of the test team) to temporarily redirect a Web service reference to an alternate location.

Additional Resources

  • For more information, see “Chapter 6 - Managing Source Control Dependencies in Visual Studio Team System” in this guide.

Last edited Jul 26, 2007 at 10:57 AM by prashantbansode, version 2

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