Thursday, January 14, 2010

Pipelines in Biztalk

Creating pipelines in ports: knowing when to use PassThru Pipelines, XML Pipelines, and when to use Custom Pipelines.

A PassThru pipeline is straightforward. On a ReceiveLocation it receives a file without further treatment, validation or field promotion. The clear text message can be captured by a Send Port with filter by Receive Port.

A XML Pipeline is more complex. It analyses the received file and determines its structure. Properties are promoted and therefore more kinds of filters become available (specially the useful namespace).

In a XML pipeline there are no limitations. The schemas can by converted, envelopes can be splitted, all options are available under the properties section. To avoid time-consuming configurations in that area – and reduce error-proneness – a Custom Pipeline should be made. It stores the configuration inside the DLL and thus can be reused in another port, or even exported to another environment without dues.

The same logic applies to SendPipelines. Usually a PassThruTransmit is enough because the message is already known in Biztalk. If a format change is needed (to Flat File i.e.) an XMLTransmit with the adequate assembler is the only option. And to place that configuration at development level, a Custom Pipeline.

Hint: For the Flat File Assembler there is no need to select a schema. According to this MSDN page If no schema is specified, run-time schema discovery is done. It was tested and confirmed. It makes development a lot easier:
  • by reducing the number of pipelines. There's no need for multiple assembler pipelines. Instead of one pipeline for each schema, a single pipeline can be used by the entire application.
  • by making them faster to upgrade. When refering schemas from external DLL's, the assembly version is required. In the past if that DLL was changed (it happens in our dev environment on a weekly basis) we had to manually correct each map and pipeline. Now the pipelines are not a problem.
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