Microsoft BizTalk 2010: Line of Business Systems Integration

If you read the product documentation, you will find that the ASDK-based adapters are built on top of the WCF Channel model and surface as custom WCF bindings. What this means is that WCF clients are able to communicate with ASDK-based adapters as if they were WCF services. Likely, the very first question you want to ask is whether the ASDK-based adapters are in fact WCF services just presented under the new fancy name. No, they are not! The use of the acronym WCF in the WCF LOB Adapter SDK is somewhat misleading; WCF forms the basis of the technology but the software does not revolve around web services. To understand how the adapters fit into the WCF infrastructure, let's recall some of the WCF fundamentals.

In order to establish communication process with clients, any WCF service must expose at least one endpoint. The WCF endpoints are based on three elements, known as the "A, B, and C" of the WCF. These three elements are:

Communication between client and service is conducted through communication channels; one channel on the client side and its equivalent on the server side. On the server side, when you instantiate the ServiceHost class, it instantiates a channel listener, which in turn builds a communication channel for the service. On the client side, the proxy creates a channel factory, which is responsible for building the channel for the client. The channels consist of binding elements, each responsible for its own part of message processing to form a stack of binding elements.

As you can notice in the previous diagram, the bottom layer in the communication channel is a transport layer, and that's exactly where the ASDK-based adapter fits within the channel stack.

The great thing about WCF is that it has been designed with extensibility in mind, which allows you to use custom transport bindings tailored to your specific needs. Much like the standard WCF transports, such as TCP, named pipes, HTTP, and MSMQ, the ASDK-based adapters are just a custom transport binding elements consumable from BizTalk applications using a standard WCF-custom adapter. As you can see in the following image, in the outbound scenario, the ASDK-based adapter instead of sending a message over the network like standard WCF transports, just communicates with the LOB system and then sends a response message to the client.

In the inbound scenario, ASDK-based adapter either monitors or listens for a notification from the target LOB system for particular events and generates a message containing event-specific data for the hosting application. We go into more details later in this and subsequent chapters.

One of the frequently asked questions in relation to the new adapters is what is the reasoning behind introducing the ASDK technology? What's wrong with good old fashioned WCF-services that have been used for years to provide access to LOB applications and are perfectly consumable from virtually all applications? Why did Microsoft re-invent the wheel? Well, these are absolutely valid questions and here is the answer. There is nothing wrong with the WCF-services; they are as good as they have always been, but there is one big "but"—only if the LOB application is relatively static. Imagine the situation where your LOB application is evolving and you, as a developer, have to expose new metadata to the client applications? You either have to update existing contracts, or implement new ones with subsequent configuration steps applied to both the host and WCF-service. This has been a major pain for the development teams working on the LOB side.

In contrast, the ASDK-based adapters provide design time metadata discovery and resolution automatically, with no efforts from the development team to make new metadata (or functionality, according to our definition of the metadata) available for consumption. Details of this process are beyond the scope of this chapter, but if you are interested in diving deeper, the sample adapters provided with the WCF LOB Adapters SDK are at your disposal. Take a look at how the Contoso sample adapter located in the C:\Program Files\WCF LOB Adapter SDK\Documents\Samples directory implements the IMetadata*group of interfaces and the magic behind the automatic metadata discovery and resolution will become clear. Implementation of the IMetadata* interfaces does require substantial efforts from the adapter developers, but the end result is certainly worth it.

Now that you are familiar with the architectural foundations, let's proceed with installation of the adapters.

The installation procedure of the BizTalk Adapter Pack 2010 is not complicated, but as with everything BizTalk, requires accuracy and some patience. The very first thing to do is make sure your system meets the prerequisite requirements. You have to have the following components installed on your computer:

Once you've completed the verification, you can proceed with the installation, which essentially is a sequence of the following steps:

From the steps above, installation of the additional client libraries is the most time consuming and error prone process. We will explore this topic in detail in the chapter dedicated to the SAP adapter.

Even though installing the WCF LOB Adapter SDK and BizTalk Adapter Pack are straightforward procedures, there is a pitfall in a 64-bit environment. If your computer is running under a 32-bit operating system, you have to install only 32-bit versions of the WCF LOB Adapter SDK and BizTalk Adapter Pack. In a 64-bit environment, the picture is a bit more complicated. First you have to install 64-bit version of the WCF LOB Adapter SDK and 64-bit version of the BizTalk Adapter Pack 2010. Then, if you are using design time tools like Visual Studio and BizTalk Admin Console or 32-bit BizTalk host instances at the runtime, you will have to install 32-bit version of the BizTalk Adapter pack and the client libraries. This probably sounds counterintuitive, but if you take into account that Visual Studio and BizTalk Admin Console are 32-bit applications and therefore can interact only with 32-bit components, such requirement becomes clear. So, don't be surprised if the BizTalk setup program run in a 64-bit environment offers you to install both 32 and 64-bit versions of the BizTalk Adapter pack 2010. Now that we are familiar with the requirements, we can begin the installation of the ASDK Adapters.

Installing the BizTalk Adapter Pack 2010

We will now install the BizTalk Adapter Pack 2010. Note, that if you are in a 64-bit environment, the setup offers to install both 32 and 64-bit versions of the BizTalk Adapter Pack 2010.

Here is the process to follow:

1. 1. In the main adapter setup window, click the link to install the relevant version of the BizTalk Adapter Pack.

2. 2. On the Welcome screen, click Next.

3. 3. Accept the license terms and click Next.

4. 4. On the Choose Setup Type screen, click the Custom button.

5. 5. On the Custom Setup screen, select the adapters you want to use and click Next.

6. 6. Click Install to begin installation.

7. 7. When the installation completes, click Finish to finalize the procedure and close the setup window.

To complete the installation of the BizTalk Adapter Pack 2010, you have to install additional client components for all adapters except SQL. For the SAP adapter covered in this book, we will provide step-by-step guidance in chapter 4. If you are planning to use the SQL adapter only, no further steps are required and at this point, you have everything you need for using and developing with the SQL adapter.

In this section, we will show you how to use the tools provided by the ASDK to enable BizTalk applications for consumption of the ASDK-based adapters. For this purpose, we will employ the Echo adapter, one of the two sample adapters supplied with the ASDK. This is a very simple adapter simulating operations to a fictitious LOB system, but at this point, we don't need anything complicated since the ASDK tools work in exactly the same fashion regardless of the adapter. So, simplicity of the Echo adapter is to our benefit—we will concentrate on the essence, leaving the complexity of the real-world adaptors to their respective chapters. As an additional bonus, the Echo adapter comes with full source code located in C:\Program Files\WCF LOB Adapter SDK\Documents\Samples directory and an installation package. As of the moment of writing this book, the setup package for the Echo adapter was not updated for use with the Visual Studio 2010 and .NET 4.0; to make you life easier, we prepared setup for .NET 4.0 32/64 bit environments and put the packages in the ZIP file containing code samples for the book. If you didn't download the samples yet, please do it now.

Echo adapter

Let's start with a brief discussion of the functionality provided by the Echo adapter. Like its big brothers from the BizTalk Adapter Pack 2010, the Echo adapter supports two message exchange patterns.

• Inbound: In the inbound scenario, the Echo adapter, being a part of the receive port infrastructure, monitors a specified file folder for new files with TXT extension; once a new file arrives, the adapter sends a notification to the BizTalk application. The notification takes the form of an XML message conforming to the following XSD schema:

• The path element contains the name of the folder being monitored for new files; the content element, as its name suggests, holds the content of a new file. If you wish to map this operation to the functionality provided by the real world adapters from BizTalk Adapters Pack 2010, it resembles the notification operations supported by the SQL adapter. When configured for notification, the adapter notifies the client application that there are data in the database meeting the specified criteria. We will discuss these operations in detail in subsequent chapters.

• Outbound: In the outbound scenario, being a part of the send port infrastructure, the adapter echoes (or repeats) an incoming string a specified number of times then sends the response back to a caller. The XSD schema for request and response messages are shown in the following image:

• The real world analogy for the EchoString operation is executing for example a select statement against a specified table by the SQL adapter and sending the result set back to a client.

To make its operations fully configurable, the Echo adapter exposes two binding properties:

• Count. This property specifies how many times incoming messages have to be echoed/repeated.

• FileSystemWatcherFolder. We will use this property to specify the folder to monitor for new *.txt files.

Since the Echo adapter is not automatically installed with the WCF LOB Adapter SDK, we will have to take care of it. The installation is straightforward and unlikely to cause difficulties.

Here are the steps:

1. 1. Navigate to C:\LOBIntegration\Chapter01\EchoAdapter\Setup32 directory and get familiar with the readme.doc file.

2. 2. Launch setup.exe and follow the setup wizard. Accept the default values for all screens.

3. 3. If you are working in a 64-bit environment, now navigate to C:\LOBIntegration\Chapter01\EchoAdapter\Setup64 and repeat the procedure.

Now that you have installed the Echo adapter, we can proceed with building the BizTalk application consuming the Echo adapter. For your convenience, we provided a complete and ready to deploy application identical to what we are going to build. The application is located in the C:\LOBIntegration\Chapter01\Walkthrough directory; you can use it as a reference to be sure that you are on the right track building your own application.

Building the BizTalk application

Our BizTalk application will consist of a single orchestration acting in a pretty much "pass-through" mode. The orchestration will receive an inbound OnReceiveEcho message from the Echo adapter, construct an outbound EchoString message by mapping the content element of the inbound message to the aName element of the outbound message, and then submit it to the adapter for echoing. The response will be received by the orchestration and written to the Application Event Log. When we complete the walkthrough, the orchestration will resemble the following image:

Here is the process to follow:

1. 1. To get started, verify that the c:\temp folder exists on your computer. If not, please create it. If you recall, the adapter exposes the FileSystemWatcherFolder property to specify the folder to monitor for the files with *.txt extension. We will use the default value which is c:\temp.

2. 2. Open Visual Studio and create a new BizTalk project with the settings shown in the following image. For the location, you can specify a folder of your choice.

3. 3. Now, the most important part. We need to generate the schemas representing the operations exposed by the adapter that you intend to use with the current application. The tool of choice for the task is the Consume Adapter Service plug-in, a metadata browser and artifacts generation tool, which you installed recently as a part of the ASDK. Besides XSD schemas, this plugin also generates a physical port binding file. This means that you can configure the port automatically by importing the binding file using the BizTalk Administration Console. The binding file typically contains physical port configuration settings including the connection string to the target LOB and the port SOAP actions based on the operations for which metadata were generated.

   • To reach the Consume Adapter Service window, first right-click on the EchoAdapterSample project and choose Add | Add Generated Items.

   • Once the Add Generated Items window appears, in the Installed Templates column, select Consume Adapter Service and click the Add button to open the Consume Adapter Service Wizard window.

   • The very first thing we need to do here is choose echoAdapterBinding from the Select a binding: drop down. If you don't see echoAdapterBinding in the drop down, make sure you installed the 32-bit version of the adapter.

   • Once the binding is set, click the Configure button to bring up the Configure Adapter dialog to configure the connection string and set credentials, URI, and binding properties.

   • The first step to generating the artifacts is establishing a connection to the target system. Most LOB systems require valid client credentials as part of the connection procedure and our Echo system is not an exception, though it is quite forgiving—after selecting Username for the Client credential type drop down, you can type in anything you like for the User name and Password, but please don't leave them blank.

   • Further, besides valid credentials, in order to establish a connection we have to provide additional parameters such as host name, port number, and other LOB application specific parameters—this is what the URI Properties tab is for. Switch to this tab and note the properties presented there. As with the user name and password, you can type in anything you like or accept the defaults.

   • While the Echo Adapter requires only three elements to build the connection URI, the real-world adapters from the BizTalk Adapters Pack 2010 require more details in order to connect to their LOB systems. For comparison, the following image shows the properties required to establish a connection to SAP:

   • Finally, we need to configure the bindings exposed by the adapter by setting the properties presented on the Binding Properties tab. For our scenario, we can accept the default values for all properties.

   • Now, click OK to close the Configure Adapter dialog and return to the Consume Adapter Service window. Note that the Configure a URI text box now contains a configured connection string, which is built from the URI properties tab values.

   • Provided the connection string we've built is correct, clicking the Connect button establishes an active connection to the Echo system. If the connection is accepted, we will see the category tree populated with outbound categories—the outbound contract type is what the Consume Adapter Service plugin chooses by default.

   • Next, we need to select the operations that we want to use in our application and add them to the list of desired operations. In the Select a category tree click the Echo Category node, then in the Available categories and operations panel, select EchoString and click the Add button. This action adds EchoString to the list of desired operations at the bottom of the screen. The last step is to help the Consume Adapter Service add-in to generate descriptive file names by setting the file name prefix at the bottom of the screen to EchoOutbound.

   • Finally, click OK to close the Consume Adapter Service Wizard window and return to Visual Studio, where we see two new files added to our BizTalk project. One file is the XSD schema for the EchoString operation, the other is an XML binding file. After deploying the application, you will import this file using the BizTalk Admin Console to create a physical WCF-Custom send port configured to perform the EchoString operation.

     Unfortunately, one of the inconveniences we have to deal with is that the Consume Adapter Service add-in doesn't allow generating artifacts for different contract types in one run. To generate the schema and binding file for the inbound operation, we need to open the Consume Adapter Service add-in again and repeat the procedure. On the Security tab, specify the username and password, for the properties on the URI Properties and Binding Properties tabs, you can accept the default values.

   • Then, once you've established a successful connection, select Service in the Select contract type drop down, click EchoCategory in the Select a category panel, and add OnReceiveEcho to the list of desired operations. Set the Filename Prefix at the bottom of the screen to EchoInbound.

   • Click OK to return to Visual Studio. Our Visual Studio solution with two new added files should now look like this:

   • Finally, to complete the schemas, double click the EchoOutbound.xsd file to open the schema editor and distinguish the EchoStringResult field. We will use this field in our orchestration.

   • Technically speaking, at this point, we have all bits and pieces required to build our BizTalk application. Before we proceed, let's make a few cosmetic changes.

     • First, rename the WcfSendPort_EchoAdapterBinding_Custom.bindinginfo.xml to SendPort.Bindinginfo.xml. Similarly, rename the WcfReceivePort_EchoAdapterBinding_Custom.bindinginfo.xml to ReceivePort.Bindinginfo.xml.

     • Next, we need to give more descriptive names for the receive port and receive location. Open the ReceivePort.bindinginfo.xml file, and change the ReceivePort and ReceiveLocation Name attributes as follows:

   • For the SendPort.bindinginfo.xml file, locate the SendPort node and change the Name attribute to SendEchoString.

4. 4. Now that we have prepared all the artifacts, we can proceed and build our sample application.

5. 5. Add a BizTalk orchestration to the project and name it ProcessEcho.

6. 6. Switch to the OrchestrationView and create three orchestration messages with the following values:

   • Identifier: msgReceiveNotification, Message Type: Walkthrough.EchoInbound

   • Identifier: msgEchoStringRequest, Type: Walkthrough.EchoOutbound.EchoString

   • Identifier: msgEchoStringResponse, Type: Walkthrough.EchoOutbound.EchoStringResponse

7. 7. To construct the outbound message, add a map to the project and name it.

8. 8. Inbound_To_Outbound.

9. 9. Specify OnReceiveEcho as the source message type, for the destination schema, specify EchoOutbound, and select EchoString as the root node. Once the source and destination schemas are set, connect the content and aName elements.

10. 10. Next, we need to sketch the orchestration flow. From the toolbox, drag on the orchestration surface the shapes in the order and with the properties as follows:

    • Shape: Receive, Name: ReceiveNotification, Activate: True, Message: msgReceiveNotification

    • Shape: Construct, Name: ConstructEchoOutbound, Message Constructed: msgEchoStringRequest. Inside the Construct drag the Transform shape and configure it with the following values: Name: Transform, Input Messages: msgReceiveNotification, Map Name: Inbound_To_Outbound, Output Messages: msgEchoStringRequest

    • Shape: Send, Name: SendEchoString, Message: msgEchoStringRequest

    • Shape: Receive, Name: ReceiveEchoResponse, Message: msgEchoStringResponse

    • Shape: Expression, Name: WriteToLog

11. 11. Configure the WriteToLog expression shape to execute the following code:

12. 12. To enable the orchestration for receiving and sending messages, we need to add two logical orchestration ports. The first port will be a one-way port for receiving an initial inbound message; the second will be a Request-Response port for sending an outbound message to the adapter for processing and receiving a response. Right-click on the Port Surface and select New Configured Port to start the Port Configuration Wizard. Here are the settings for the first one-way port.

    • Name: ReceiveInitialEcho

    • Port Type: Create New Port, Port Type Name: InitialEchoType, Communication Pattern: One-Way, Access Restriction: Internal

    • Port Direction of Communication: I will always be receiving messages on this port, Port Binding: Specify later

13. 13. Run the Wizard one more time to create a logical port for the outbound operation.

    • Name: SendEchoString

    • Port Type: Create New Port, Port Type Name: SendEchoStringType, Communication Pattern: Request-Response, Access Restriction: Internal

    • Port Direction of Communication: I will always be sending request, and receiving response on this port, Port Binding: Specify later

14. 14. Join the logical ports with the relevant shapes. Connect Request of the ReceiveNotification receive port with the ReceiveNotification shape. For the SendEchoString send port, connect Request with the SendEchoString shape, and Response with the ReceiveEchoResponse shape. When you finish, the orchestration should match the following image:

15. 15. Build the application and address error messages, if any.

16. 16. The last thing to do before we deploy the application is specify a strong name key for the application assembly, and provide the name for the BizTalk application. In the Solution Explorer, right-click on the project name and select Properties. From the Project Properties window, switch to the Signing tab to specify a strong name key file. You can either generate a new, or use any existing key file from your computer. Then, activate the Deployment tab and type Chapter01_Walkthrough for the application name.

17. 17. Almost there; we are finally at the deployment stage. Go to the BizTalk Admin Console and create a new application named Chapter01_Walkthrough. You have to create the application first; otherwise Visual Studio will deploy the solution in the default application in the group.

18. 18. In the Solution Explorer, right-click on the solution name, select Deploy, and wait for the message confirming that the deployment succeeded.

19. 19. To complete the deployment, we need to create the application physical ports. This is where the binding files, generated for us by the Consume Adapter Service plugin, come into play. Open the BizTalk Administration Console, expand the Applications node, right-click Chapter01_Walkthrough, and select Import|Bindings. Navigate to the solution directory and import the binding file for the receive port. Then, repeat the procedure to import the bindings for the send port. Disregard a pop-up message informing you of the application name not matching and click Yes.

20. 20. For security reasons, the Consume Adapter Service addin doesn't include the usernames and passwords when generating binding files. For the physical ports, we have to set them manually using the WCF-Custom Transport Properties window. Let's start with the send port. In BizTalk Administration Console, double-click the SendEchoString port, then click Configure, switch to the Credentials tab, and type in any username and password.

21. 21. Specify the username and password for the receive location. In the BizTalk Admin Console, double-click the EchoWcfCustom_ReceiveNotification receive location and then click Configure to open the WCF-Custom Transport Properties window. As you can see, for the receive location, this window has a slightly different look. There is no Credentials tab; instead, you have to switch to the Other tab and specify the username and password there.

22. 22. The last step before we start the application is to bind the orchestration. In the BizTalk Administration Console, double click ProcessEcho orchestration to open the Orchestration Properties window. Activate the Bindings tab and set the properties as shown in the following image:

23. 23. Click OK to close the Orchestration Properties window and then start the application.

If we submit a file to the c:\temp folder monitored by the adapter, we will get the following error message:

The adapter failed to transmit message going to send port "SendEchoString" with URL " echo://host/temp?EchoPrefix=pre ". It will be retransmitted after the retry interval specified for this Send Port. Details:"Microsoft.ServiceModel.Channels.Common.UnsupportedOperationException: Incorrect Action
<BtsActionMapping xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<Operation Name="EchoString" Action="Echo/EchoString" />
</BtsActionMapping>. Correct the specified Action, or refer to the documentation on the allowed formats for the Actions. Note that Actions are case-sensitive.

The problem is exactly what the error message is telling us—the SOAP action settings applied to the send port are not understood by the adapter. One of the most often asked questions on the MSDN forums is "I imported bindings with the SOAP action settings as generated by the Consume Adapter Service plug-in, so why are they nor understood by the adapter?". We will demystify the subject and shed some light on how the WCF-custom adapter processes the actions shortly, right after we finish the walkthrough. For now, to fix the problem and complete the application, go to the BizTalk Admin Console and do the following:

1. 1. Double-click the SendEchoString send port. In the Send Port Properties windows click Configure to open the WCF-Custom Transport Properties window.

2. 2. In the Action text box of the SOAP Action Header section, note the value of the Name attribute, which is EchoString. What you have to do is to make your orchestration logical send port name match the value of the Name attribute. The first option is to change the logical port name from Operation_1 to EchoString and then, of course, to re-deploy the application.

3. 3. An alternative option, if you don't want to redeploy the application, is to set the Name attribute value to Operation_1, so that the content of the Action box looks as follows:

4. 4. Although from a pure technical standpoint this is a perfectly valid solution, using such non-descriptive names is a questionable practice and should be avoided. We presented it here with the only purpose being to illustrate the concept. The best approach is not to leave the operation name with the default value Operation_1, but to give it a descriptive name upon designing the orchestration and then adjust the physical port action mapping.

   So, let's do it right and just change the logical port operation name to EchoString. Once done, re-deploy the application. Now, you can create a file containing a single word "Echo", drop it to the C:\temp folder, and watch the event log for the echoed messages returned by the Echo adapter. Please don't forget, the file must have a TXT extension.

Now, as promised, let's take a deeper look at the SOAP actions and how the WCF-Custom adapter deals with them. The idea behind the SOAP actions is quite simple. Essentially, the SOAP action is just a tag attached to the incoming WCF messages telling the adapter what operation it has to perform.

To illustrate the concept by a concrete example, let's refer to the source code provided with the Echo adapter. The point of our interest is the Execute method of the Microsoft.ServiceModel.Channels.Common.IOutboundHandler interface. This interface is one of the core interfaces that all ASDK-based adapters supporting outbound operations must implement. The Execute is called by the ASDK runtime to perform an outbound operation. Here is the implementation:

The code is self-explanatory and as you can clearly see, is action-centric. If the action coming with the SOAP header is recognized, the adapter performs the requested operation, if not, then the adapter responds with "Invalid Operation" exception. Since the Echo adapter exposes only one operation, using actions may seem unnecessary, but imagine the situation when an adapter exposes multiple operations? In such cases, using the SOAP actions is quite a logical way to help the adapter to decide what operation to perform.

There are two different ways to associate a BizTalk message with the appropriate SOAP action (or to attach the appropriate processing tag as you wish). One is to configure physical send ports using so called Action Mappings. The other is to set the actions dynamically at runtime.

Action Mappings

You will use the Action Mappings in the majority of cases—this is the easiest way to configure physical ports since the Consume Adapter Service Wizard does most of the job. For each operation that you selected at the design time, the Consume Adapter Service Wizard will generate a corresponding Operation entry inside the BtsActionMapping wrapper and place the mapping into the physical port binding file it will generate. In the general form, the action mapping looks as follows:

To process the actions mappings and attach the SOAP actions tags to incoming messages, the WCF-Custom adapter uses the following algorithm:

When the outbound message leaves an orchestration, the orchestration instance sets the BTS.Operation context property with the logical port operation name. Once the subscription mechanism pulls the message from the message box and hands it over to the physical port for processing, the WCF-Custom adapter tries to look up the actions map for the Operation with the Name matching the BTS.Operation property. If a match is found, then the adapter attaches the corresponding Action value to the message and sends it to the custom binding for execution. If a match was not found, then the WCF-Custom adapter treats the entire BtsActionMapping as one big action, so the custom binding will get the following action:<BtsActionMapping><Operation Name="Operation 1" Action =......</BtsActionMapping> with quite a predictable consequence—"Invalid action" exception. So, the rule is clear: for each orchestration outbound operation, there must be an Operation entry in the corresponding physical port action mappings with the Name attribute value matching the orchestration operation name.

It is important to note that for the content-based routing scenarios, where you don't use orchestrations and rely solely on the functionality provided by the messaging engine, you don't have to write a custom pipeline component to set the BTS.Operation context property. Luckily, the WCF-custom adapter supports an alternative single action format.

Essentially, this means that all messages arriving to the send port configured for the single action processing will be tagged with the same action regardless of the BTS.Operation context property. Since the Echo adapter supports only one operation, the single action approach is an alternative solution perfectly applicable to our sample application.

YourOutboundMessage(WCF.Action)="DesiredAction"

At this point, you essentially have all the necessary information to start building applications that rely on the ASDK-based adapters. Nonetheless, as with any serious technology, which the ASDK no doubt is, there are areas and features which can become the source of headaches or make your work less productive if used indiscriminately. And, as with any serious technology, there are tools to help you effectively resolve potential problems.

In this section, we will discuss the following topics, applicable to all ASDK-based adapters:

Timeouts

If you've followed the walkthrough, you should have noticed the group of timeout-related binding properties available at the design time on the Binding Properties page of the Configure Adapter dialog.

After you imported the binding file generated by the ASDK, these properties are accessible through the Bindings tab of the WCF-Custom Transport properties dialog.

The purpose of each property and the default values as set by the ASDK are listed in the following table:

Property	Purpose
openTimeout	Open connection timeout. The default value is 1 minute.
closeTimeout	Close connection time out. The default value is 1 minute.
sendTimeout.	Outbound request-response timeout. This property specifies for how long the adapter waits for the response from the target LOB before throwing an exception. The default value is 1 minute.
receiveTimeout	Receive operation timeout. Essentially, this property specifies for how long adapter waits for an inbound message from the target LOB. Default value is 10 minutes.

When dealing with the timeout exceptions in the outbound scenarios, it may be tempting to solve the problem by simply increasing the sendTimeout value. However, your first line of defense should be communicating with the LOB application administrator to determine whether the problem can be resolved by optimizing performance on the LOB application side. Masking the problem by blindly increasing the sendTimeOut value is definitely not the best solution.

For the inbound operations, you have to set the receiveTimeout property to the value large enough to not interfere with your particular receive location configuration. If you are pulling your hair out trying to figure out why your adapter is behaving totally "unexplainably"—for example, polling the database at random with no apparent pattern intervals instead of using the dedicated configuration properties, the first thing to check is the receiveTimeout settings. In many cases, adjusting this property magically resolves even seemingly unrelated problems. We will return to this subject in subsequent chapters. The default value is 10 minutes; the maximum supported value is 24.20:31:23.6470000 (24 days).

In this chapter, we've laid a good foundation for discussing the features and functionality of the adapters from BizTalk Adapters Pack 2010. We have covered:

In the next chapter, we will introduce you to the WCF SQL Adapter, probably the most widely used adapter from the BizTalk Adapter Pack 2010.