SCAAsyncRequest node

The SCAAsyncRequest node sends a request to a business process that is running on WebSphere Process Server, but the node does not wait for the associated response to be received. However, the SCAAsyncRequest node does wait for an acknowledgment before continuing with the message flow. The response to the Process Server request is received by the SCAAsyncResponse node, which can be in the same message flow or in a separate message flow. The nodes are used as a pair, and correlate responses against the original requests.

The SCAAsyncRequest node is the first half of the asynchronous request and response node pair. The SCAAsyncRequest node sends a request to a business process that is running on WebSphere Process Server. The request is sent by the SCAAsyncRequest node, but the SCAAsyncRequest node does not receive the response. The response is received by a SCAAsyncResponse node that is running on a different thread. The SCAAsyncResponse node is typically at the beginning of a different message flow; however, it must be in the same integration server as the SCAAsyncRequest node.

A Broker SCA definition is required to configure both the SCAAsyncRequest node and the SCAAsyncResponse node. The Broker SCA definition contains specific data related to the Process Server binding.

The SCAAsyncRequest node is contained in the SCA drawer of the palette, and is represented in the IBM Integration Toolkit by the following icon:

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You can change the operation that should be invoked by changing the value in the following location in the local environment:

LocalEnvironment.Destination.SCA.Request.Operation

For a Web Services binding, you can change the URL to which the request is sent. Change the value in the following location in the local environment:

LocalEnvironment.Destination.SCA.Request.Binding.WebServices.Transport.HTTP.WebServiceURL

For an MQ binding, you can change the Request Queue Manager and Request Queue by changing the values in the following locations:

LocalEnvironment.Destination.SCA.Request.Binding.MQ.queueManagerName
LocalEnvironment.Destination.SCA.Request.Binding.MQ.queueName

You can store context data in the following location in the local environment. The SCAAysncResponse node can later retrieve this data.

LocalEnvironment.Destination.SCA.Request.UserContext

LocalEnvironment.Destination.SCA.Request.Binding.WebServices.Transport.HTTP.KeyAlias

LocalEnvironment.Destination.SCA.Request.Binding.WebServices.Transport.HTTP.EnableCRLChecking

Ensure that the message set contains a Broker SCA definition with an extension of .outsca with which to configure the SCAAsyncRequest node.

There are two methods of putting an instance of the SCAAsyncRequest node into a message flow: you can either drag an instance of the node from the node palette, or drag a Broker SCA definition with an extension of .outsca from a message set onto the message flow editor canvas.

Dragging a node onto the canvas

If you have dragged an instance of the node from the palette onto the canvas, use one of the following methods to start to configure it:

• Drag a Broker SCA definition with an extension of .outsca onto the node.
• Type the file name in the SCA file name option in the Properties view of the node.
• Browse to the file (SCA file name option in the Properties view of the node.)

Dragging a .outsca file onto the canvas

• If the .outsca file contains a WSDL that has only a single, one-way operation defined, a SCARequest node is created.
• If the .outsca file contains a WSDL that only has request-response operations, you first select the operation, and say whether you want the outbound request to be sent synchronously or asynchronously. For a synchronous request, a SCARequest node is created and configured. For an asynchronous request, a pair of SCAAsyncRequest and SCAAsyncResponse nodes are created and configured.
• If the .outsca file contains a WSDL that has a mixture of one-way and request-response operations defined, and you select a one-way operation, a SCARequest node is created.

The values for many of the node properties are provided in the Broker SCA definition. The properties of the node are displayed in the Properties view. All mandatory properties for which you must enter a value (properties that do not have a default value defined) are marked with an asterisk.

1. Optional: On the Description tab, enter a Short description, a Long description, or both. You can also rename the node on this tab.
2. On the Basic tab, set the Unique identifier and Broker SCA definition properties.
   • Unique identifier. You must specify the unique string that is common to your pair of SCAAsyncRequest and SCAAsyncResponse nodes. This property is mandatory.
   • In Broker SCA definition, specify the name of the Broker SCA definition that contains configuration properties for the SCAAsyncRequest node. If you have created the node by dragging a Broker SCA definition from a message set onto the Message flow editor canvas, this property is preset to the name of the Broker SCA definition. If you created the node by selecting it from the palette, you can set this property in one of the following ways:
     • If you have a Broker SCA definition, you can select it from the Broker SCA definitions by clicking Browse.
     • Type a file name that is relative to the message set project in which the Broker SCA definition exists.
     • If you have Broker SCA definitions, but no message set, you can create a message set:
       1. Click Browse to open the Broker SCA Definition Selection pane.
       2. Click Import/Create New to open the Import Broker SCA definition wizard.
       3. Enter the message set name and message set project name, then click Next.
       4. Choose the relevant option:
          • If your Broker SCA definition exists in your workspace, click Use resources from the workspace, and select the Broker SCA definition.
          • If your Broker SCA definition is in the file system, click Use external resources, select the Broker SCA definition, click Next.
       5. Select the Broker SCA definition to import.
       6. Click Finish. A new message set project and message set are created with message definitions. The Broker SCA definition is added to the Broker SCA Definitions folder.
       7. Select the Broker SCA definition from the Broker SCA Definition Selection window, then click OK.
     • If you have a message set but no Broker SCA definition, generate a Broker SCA definition by following the instructions in Message Sets: Generating a Broker SCA definition from a message set.
     • Drag a Broker SCA definition from a message set onto the node.
3. On the Binding tab, specify properties that relate to the WebSphere Process Server binding. Some of the properties on this tab are derived from the Broker SCA definition.
   • The value of the Binding type property is derived from the binding information in the Broker SCA definition. It is read-only. Possible values are:
     • WebService. Requests from WebSphere Process Server are sent as SOAP messages over the HTTP transport. See the WSDL properties table in Terminals and properties for details of binding properties that are either supplied by the Broker SCA definition, or that you need to set.
     • MQ. Requests from WebSphere Process Server arrive as WebSphere MQ messages. See the MQ properties table and the Transactionality table in Terminals and properties, for details of binding properties that are either supplied by the Broker SCA definition, or that you need to set.

For information on configuring the SCAAsyncRequest node to use SSL, see Setting up a public key infrastructure and review the information that relates to the SOAPAsyncRequest node.

The SCAAsyncRequest node terminals are described in the following table.

The following tables describe the node properties. The column headed M indicates whether the property is mandatory (marked with an asterisk if you must enter a value when no default is defined); the column headed C indicates whether the property is configurable (you can change the value when you add the message flow to the BAR file to deploy it).

The Description properties of the SCAAsyncRequest node are described in the following table.

The Basic properties of the SCAAsyncRequest node are described in the following table.

The Binding property of the SCAAsyncRequest node is described in the following table.

The WSDL properties are described in the following table. These properties are shown only if the binding type is Web Services.

The MQ properties are described in the following table. These properties are shown only if the binding type is MQ.

The Transactionality property of the SCAAsyncRequest node is described in the following table.