Wednesday 24 December 2008

Identifying a BizTalk process

When using multiple BizTalk Hosts the process relating to each host can be identified using the following command line instruction:

tasklist /SVC /FI "IMAGENAME eq btsntsvc.exe"

This will display a list of BizTalk processes with the name of the Host and the PID. Note the PID for the host you are interested in. Match the correct PID with the process listed in Task Manager or the Visual Studio  Attach To Process dialog.

Tuesday 23 December 2008

Resolving Schema Type Name Clashes

A common schema related error that may occur when building BizTalk projects that include schemas is:

BEC2017: Node "<Schema>" - This schema file has a TypeName that collides with the RootNode TypeName of one of its root nodes. Make sure that they are different.

The reason for this is quite simple - when the project is compiled, a .NET class will be generated for each top level element in your schema. If you have two schemas which share the same top level element name a clash will occur.

This is quite a common scenario and it is not always practical (or even possible) to change the element names. The solution is to change the generated type name for the schema. To do so, select the schema in the Solution Explorer and press F4 to display the Properties window. Then change the Type Name property so that it is not the same as any of the top level elements.

Monday 22 December 2008

Default content in Maps

On a couple of occasions recently I have hit upon the need to use default content in some elements of a message generated via a map. More specifically I had an orchestration which did the following:

  • Defined an input and output schema that contained a standard header section
  • Makes calls to external .NET components, other orchestrations and send ports
  • If all works OK, a suitable response message is returned
  • In the event of a failure, an exception handler is invoked which constructs a new message to send to a common error logging orchestration before creating and returning a response message to the caller

The area of interest is the message sent to the error logging orchestration. This schema contains the standard header along with error information to be logged (for which each element defined as a distinguished field) i.e.

<xsd:element name="exception_details">
      <xsd:element name="type" type="xsd:string" />
      <xsd:element name="description" type="xsd:string" />
      <xsd:element name="error_source" type="xsd:string" />
      <xsd:element name="details" type="xsd:string" />

To create an instance of this message I transform the original request (to create the standard header) and insert the error details via code in a message assignment shape.


msgException.exception_details.description = ex.Message;
msgException.exception_details.details = ex.ToString();
msgException.exception_details.error_source = "orch name";
msgException.exception_details.type = "details here";

However, in order to programmatically insert the content into these elements, the elements had to exist in the new message! If it does not I get an XPath error when trying to set the distinguished property values.

To ensure that the elements exist I used the useful but often overlooked property of the element - Value. To find this open the Map Designer, select the target element and go to the Properties window. There you will see a Value property which can be used to set a default value for the element or <empty>. In this case <empty> was most appropriate giving message content of:

        ...header content omitted

This allowed me to set the error detail programmatically as required. Voila!

How can I use Fiddler to debug BizTalk messages?

When using HTTP, SOAP or WCF send ports it can be incredibly useful to view the content of messages that are sent on the wire. This allows you to inspect the headers (SOAP or HTTP). Fiddler is a simple but fantastic tool to allow you to do this.

By default, Fiddler will not trace any messages sent to endpoints by BizTalk as it does not use WinInet. However, BizTalk send ports can be configured to use a proxy allowing Fiddler to intercept them. On the Send Port tick the Use Proxy checkbox and set the Server to and the port to 8888. For dynamic ports, set the following properties (as applicable to the adapter being used)

// Debug via fiddler
msgSendRequest(SOAP.UseProxy) = true;
msgSendRequest(SOAP.ProxyAddress) = "";
msgSendRequest(SOAP.ProxyPort) = 8888;

Note that this needs to be removed when Fiddler is not running since traffic directed to the proxy will not be received by anything.