Welcome!

Microsoft Cloud Authors: Andreas Grabner, Stackify Blog, Liz McMillan, David H Deans, Automic Blog

Related Topics: Microsoft Cloud

Microsoft Cloud: Article

.NET Feature — Creating Custom WCF Behaviors

Apply cross-cutting logic to your services

Now that you've seen how to use an interceptor to create common logic (see Listing 1), and how to use a behavior to load that interceptor (see Listing 2), let's see how the behavior can be instructed to load via configuration files. You may first want to refer back to Listing 1 to see that the InsertLogging class inherits from the BehaviorExtensionElement class; this is the first thing you'll need to do if you want to use configured behaviors. When this is done, you must override that class's BehaviorType property and CreateBehavior method, as is shown in Listing 3.

The BehaviorType property in Listing 3 returns the type of behavior, which happens to be InsertLogging. CreateBehavior is a "creational method" that returns an instantiation of a new InsertLogging object. Altogether, this provides the configuration system the information it requires to load the behavior class at the appropriate time.

Let's move on to see what you'll need to put in your configuration files to associate a behavior with a specific service. The first part of the system.serviceModel section from web.config is presented in Listing 4.

The key thing to notice in Listing 4 is the behaviorConfiguration attribute. This tells the configuration system that a specific behavior, in this case one named LogBehavior, should be configured for use with this service. Listing 5 shows the behaviors section where you can see the actual definition for that behavior. Note that it has an element named LoggingBehavior, which indicates the "extension" to be associated with LogBehavior.

Listing 5 shows that the behaviorExtensions element contains a directive to add a custom .Net type named WCF.Behaviors.InsertLogging that can be found in the assembly named WCF.Behaviors. If you have set up your configuration file properly then the WCF runtime will acquire this information prior to opening the ServiceHost and will execute the logic found in Listing 3 and then the logic in Listing 2. If all has gone according to plan up to this point then when a message flows into any service endpoint, the common logging logic found in Listing 1 will be executed.

How To Inject Client Information into the SOAP Headers
Now let's see how we can use a client-side Message Inspector and a Contract Behavior so that we can track which applications use a given version of a contract. Let's say that we always want to enforce this behavior, so we decide to use attributes to tell the WCF runtime to always load the behavior on the client. Listing 6 shows a portion of a class named InsertClientInfo. Notice that it inherits from the Attribute class and also implements IClientMessageInspector and IContractBehavior.

In summary, the logic in Listing 6 creates a custom MessageHeader using the ClientInfo type (see Listing 9), and adds that header to the request message. This all occurs before that message is sent through the proxy's channel stack and over the wire to the service. To put this interceptor into the WCF runtime on the proxy side, we can create code in the ApplyClientBehavior method so that a reference to the InsertClientInfo class will be added into the MessageInspectors collection of the proxy's clientRuntime. This is shown in Listing 7.

Now we have to alter the client proxy code so the ApplyClientBehavior method will be invoked. To do this we can either edit the output file produced by Svcutil.exe, or if we use the Visual Studio IDE to add a service reference to a project, we can edit the .cs file that it adds. Listing 8 shows how an attribute may be added to the code for the client proxy.

In this case, I used Visual Studio to add the service reference; this is why you see information from the CodeDom. Since I want to capture client information for all calls to a given service contract, I have to know the name of either the service interface class or the class that implements this interface. Lucky for me, I happen to know that the interface is named IBargainAirService. To tell the WCF runtime that it should load a behavior, the IBargainAirService interface has been decorated with the [WCF.Behaviors.InsertClientInfo] attribute. By choosing to decorate the IBargainAirService interface with this attribute, the effect will be that all classes in the proxy that implement this interface will have this behavior applied to them. Now, whenever a client opens a channel factory out to the service, the logic in Listing 7 will be invoked, and when the client sends a message out to the endpoint that contains this contract, the code in Listing 6 will step in to intercept the call. Pretty cool, eh?

Conclusion
We've covered a lot of ground in this article, from the WCF architecture that supports extensibility, to a few code samples showing some of the possibilities. I hope that you can now see how this powerful feature may be tapped to apply cross-cutting logic to your services. Perhaps you've even caught a glimpse of the endless possibilities that lie beyond.

More Stories By Rob Daigneau

Rob Daigneau is the Director of Architecture for Monster.com, one of the most visited web sites in the world. Rob has over 18 years of experience designing and implementing enterprise-class applications for a broad array of industries from manufacturing, to financial services, to retail. He is also a frequent speaker at conferences such as VS Live! and DevTeach, and writes on a number of industry-related topics for .NET Developer's Journal as well as at www.DesignPatternsFor.Net

Comments (2) View Comments

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


Most Recent Comments
John Fitzpatrick 05/14/08 02:56:29 PM EDT

Great article. The step by step description was really helpful and made this complicated topic digestible.
Thanks

Sachin 11/13/07 10:41:34 PM EST

Hi,

I saw this article and i am very impressed by this message logging idea. If you can send me the sample code for the given article then i will try to inject the policy injection for tracing and exception handling in the WCF services using Application Block.

Regards,

Sachin

@ThingsExpo Stories
The current age of digital transformation means that IT organizations must adapt their toolset to cover all digital experiences, beyond just the end users’. Today’s businesses can no longer focus solely on the digital interactions they manage with employees or customers; they must now contend with non-traditional factors. Whether it's the power of brand to make or break a company, the need to monitor across all locations 24/7, or the ability to proactively resolve issues, companies must adapt to...
SYS-CON Events announced today that Datanami has been named “Media Sponsor” of SYS-CON's 21st International Cloud Expo, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Datanami is a communication channel dedicated to providing insight, analysis and up-to-the-minute information about emerging trends and solutions in Big Data. The publication sheds light on all cutting-edge technologies including networking, storage and applications, and the...
SYS-CON Events announced today that EnterpriseTech has been named “Media Sponsor” of SYS-CON's 21st International Cloud Expo, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. EnterpriseTech is a professional resource for news and intelligence covering the migration of high-end technologies into the enterprise and business-IT industry, with a special focus on high-tech solutions in new product development, workload management, increased effi...
SYS-CON Events announced today that MobiDev, a client-oriented software development company, will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place October 31-November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. MobiDev is a software company that develops and delivers turn-key mobile apps, websites, web services, and complex software systems for startups and enterprises. Since 2009 it has grown from a small group of passionate engineers and business...
SYS-CON Events announced today that GrapeUp, the leading provider of rapid product development at the speed of business, will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place October 31-November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Grape Up is a software company, specialized in cloud native application development and professional services related to Cloud Foundry PaaS. With five expert teams that operate in various sectors of the market acr...
SYS-CON Events announced today that Ayehu will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place on October 31 - November 2, 2017 at the Santa Clara Convention Center in Santa Clara California. Ayehu provides IT Process Automation & Orchestration solutions for IT and Security professionals to identify and resolve critical incidents and enable rapid containment, eradication, and recovery from cyber security breaches. Ayehu provides customers greater control over IT infras...
Artificial intelligence, machine learning, neural networks. We’re in the midst of a wave of excitement around AI such as hasn’t been seen for a few decades. But those previous periods of inflated expectations led to troughs of disappointment. Will this time be different? Most likely. Applications of AI such as predictive analytics are already decreasing costs and improving reliability of industrial machinery. Furthermore, the funding and research going into AI now comes from a wide range of com...
In this presentation, Striim CTO and founder Steve Wilkes will discuss practical strategies for counteracting fraud and cyberattacks by leveraging real-time streaming analytics. In his session at @ThingsExpo, Steve Wilkes, Founder and Chief Technology Officer at Striim, will provide a detailed look into leveraging streaming data management to correlate events in real time, and identify potential breaches across IoT and non-IoT systems throughout the enterprise. Strategies for processing massive ...
SYS-CON Events announced today that Conference Guru has been named “Media Sponsor” of SYS-CON's 21st International Cloud Expo, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. A valuable conference experience generates new contacts, sales leads, potential strategic partners and potential investors; helps gather competitive intelligence and even provides inspiration for new products and services. Conference Guru works with conference organi...
SYS-CON Events announced today that Cloud Academy named "Bronze Sponsor" of 21st International Cloud Expo which will take place October 31 - November 2, 2017 at the Santa Clara Convention Center in Santa Clara, CA. Cloud Academy is the industry’s most innovative, vendor-neutral cloud technology training platform. Cloud Academy provides continuous learning solutions for individuals and enterprise teams for Amazon Web Services, Microsoft Azure, Google Cloud Platform, and the most popular cloud com...
SYS-CON Events announced today that CA Technologies has been named "Platinum Sponsor" of SYS-CON's 21st International Cloud Expo®, which will take place October 31-November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. CA Technologies helps customers succeed in a future where every business - from apparel to energy - is being rewritten by software. From planning to development to management to security, CA creates software that fuels transformation for companies in the applic...
SYS-CON Events announced today that TMC has been named “Media Sponsor” of SYS-CON's 21st International Cloud Expo and Big Data at Cloud Expo, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Global buyers rely on TMC’s content-driven marketplaces to make purchase decisions and navigate markets. Learn how we can help you reach your marketing goals.
Internet of @ThingsExpo, taking place October 31 - November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with 21st Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. The Internet of Things (IoT) is the most profound change in personal and enterprise IT since the creation of the Worldwide Web more than 20 years ago. All major researchers estimate there will be tens of billions devic...
"MobiDev is a Ukraine-based software development company. We do mobile development, and we're specialists in that. But we do full stack software development for entrepreneurs, for emerging companies, and for enterprise ventures," explained Alan Winters, U.S. Head of Business Development at MobiDev, in this SYS-CON.tv interview at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
SYS-CON Events announced today that IBM has been named “Diamond Sponsor” of SYS-CON's 21st Cloud Expo, which will take place on October 31 through November 2nd 2017 at the Santa Clara Convention Center in Santa Clara, California.
SYS-CON Events announced today that Telecom Reseller has been named “Media Sponsor” of SYS-CON's 21st International Cloud Expo, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Telecom Reseller reports on Unified Communications, UCaaS, BPaaS for enterprise and SMBs. They report extensively on both customer premises based solutions such as IP-PBX as well as cloud based and hosted platforms.
We build IoT infrastructure products - when you have to integrate different devices, different systems and cloud you have to build an application to do that but we eliminate the need to build an application. Our products can integrate any device, any system, any cloud regardless of protocol," explained Peter Jung, Chief Product Officer at Pulzze Systems, in this SYS-CON.tv interview at @ThingsExpo, held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA
Multiple data types are pouring into IoT deployments. Data is coming in small packages as well as enormous files and data streams of many sizes. Widespread use of mobile devices adds to the total. In this power panel at @ThingsExpo, moderated by Conference Chair Roger Strukhoff, panelists looked at the tools and environments that are being put to use in IoT deployments, as well as the team skills a modern enterprise IT shop needs to keep things running, get a handle on all this data, and deliver...
The current age of digital transformation means that IT organizations must adapt their toolset to cover all digital experiences, beyond just the end users’. Today’s businesses can no longer focus solely on the digital interactions they manage with employees or customers; they must now contend with non-traditional factors. Whether it's the power of brand to make or break a company, the need to monitor across all locations 24/7, or the ability to proactively resolve issues, companies must adapt to...
SYS-CON Events announced today that Enzu will exhibit at SYS-CON's 21st Int\ernational Cloud Expo®, which will take place October 31-November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Enzu’s mission is to be the leading provider of enterprise cloud solutions worldwide. Enzu enables online businesses to use its IT infrastructure to their competitive advantage. By offering a suite of proven hosting and management services, Enzu wants companies to focus on the core of their ...