More on SOAP extensions

In a previous tip, I explained how SOAP Extensions allow you to plug in and capture/manipulate the SOAP message in ASP.NET as it travels through the ASP.NET Web service chain of events -- from IIS to the ASP.NET ISAPI extension, through the HTTP modules down to the HTTP Handler. I also explained how there are four events (BeforeDeserialize, AfterDeserialize, BeforeSerialize and AfterSerialize) that allow you to inspect or modify the SOAP request message before/after it is deserialized into an object, and before/after the response object is turned back into a SOAP message. Now, I give you the code for the SoapLogger utility. This source code uses some pretty advanced features of .NET, such as the creation of custom attributes, manipulation of memory and file streams, and inheriting and overriding .NET Framework classes and methods (respectively) to implement your own functionality. To use this example, do the following:

1. Create a new C# class library project called "SoapLogger".
2. Download the source code and paste it into the Class1.cs file that was provided by Visual Studio.NET when you created the new project. Be sure to remove any existing code from that file before pasting this code into it.
3. Compile the project. It will create a new assembly in the bin directory of your project called SoapLogger.dll
4. Open the Web services project you want to add logging to. Open the actual ASMX file (or rather, its code behind file .cs or .vb).
5. Add a reference to the SoapLogger.dll by right-clicking the project name in the solution explorer and selecting "Add reference..." and the Add Reference dialog will appear.
6. Find your SoapLogger assembly in the list (or use the browse feature) and create a reference to the component.
7. Add an attribute to the Web Method you want to log. For example, I used the following code in the method signature to log the results of the UpdateAffiliateDetail Web Method:

   (Notice the underscores in VB.NET!)

   Alternatively, you can send in a location if you don't like the default location and name using a property of the SoapLogger attribute:

8. Compile and test your Web service. Once you do, you will see a log file that contains the SOAP messages for each time your Web Method is called.

Here's the C# code:

Notice that the SoapLogger class derives from the SoapExtension class. This is how you "plug into" the architecture of the HTTP Handler for Web services. Then, you must override several methods, such as Initialize, GetInitializer (allows you to retrieve the properties of the attribute, or set default values), ChainStream (allows you to copy off the memory stream for processing) and most importantly the ProcessMessage method, that allows you to determine which stage the SOAP request/response is currently in. If you take a look in the example above in the ProcessMessage method, I only test for two ...

Digg This!     StumbleUpon     Del.icio.us

RELATED CONTENT SOAP Denmark is first to adopt Universal Business Language XML-based financial standard gets new support SOAP test tool adds WS-Security, MIME support Survey: IT spending back from the dead WASP Server adds to XML Schema support IBM, Microsoft on opposite sides of standards fence WS orchestration 'power struggle' under way, IDC says Internet millionaire gives integration a whirl WS-I accepting comments on latest efforts Grand Central adds directory to integration service Microsoft .NET Web services Microsoft preps .NET 4.0 - framework improves on REST, MVC, JQuery support How do I balance throughput requirements and interoperability? APM software traces transactions across tiers, technologies How you can learn M Grammar for Oslo modeling Legacy modernization opens Windows for publisher Former .NET Web developers ride Ruby and Rails application framework Microsoft Oslo at PDC: Dial 'M' for modeling language Yahoo proxy fight looms New Microsoft site for architects LAMP coders go hybrid route Microsoft .NET Web services Research .NET Developer Programming Indigo DataSets and Web services don't mix Security in .NET 2.0 Tracking down managed memory leaks Handling exceptions in .NET .NET Compact Framework graphics The Data Access Application Block A great .NET resource: .Net2TheMax Delegates vs. interfaces in .NET Project structure best practices

RELATED GLOSSARY TERMS Terms from Whatis.com − the technology online dictionary Common Language Infrastructure  (SearchSOA.com) Visual J#  (SearchSOA.com)

RELATED RESOURCES 2020software.com, trial software downloads for accounting software, ERP software, CRM software and business software systems Search Bitpipe.com for the latest white papers and business webcasts Whatis.com, the online computer dictionary

SoapMessageStages -- BeforeDeserialize and AfterSerialize. Why is that? Because this is when the message is actually a SOAP message, and is not in its object form.

You can extend this sample and build all sorts of inspection and logging into your Web service applications. This should give you plenty of meat to cut your teeth on. Until next time...

About the Author

[IMAGE]Robert Tabor is a Microsoft Certified Professional in Visual Basic with over six years of experience developing n-tier Microsoft-centric applications for some of the world's most prestigious companies and consulting organizations, such as Ernst & Young, KPMG, Cambridge Technology Partners, Sprint, American Heart Association, and the Mary Kay Corporation. Bob is the author of Microsoft .NET XML Web services by Sams Publishing, and contributes to SoapWebservices.com and LearnVisualStudio.NET. He is currently working on initiatives within Mary Kay, the second largest eCommerce site in retail volume on the net, of how to utilize .NET within their e-business group.

Rate this Tip To rate tips, you must be a member of SearchSOA.com. Register now to start rating these tips. Log in if you are already a member. DISCLAIMER: Our Tips Exchange is a forum for you to share technical advice and expertise with your peers and to learn from other enterprise IT professionals. TechTarget provides the infrastructure to facilitate this sharing of information. However, we cannot guarantee the accuracy or validity of the material submitted. You agree that your use of the Ask The Expert services and your reliance on any questions, answers, information or other materials received through this Web site is at your own risk.