Integrating Web Services with Datastage: May 2013

Web services expose operations of custom functions accessible to applications through internet or intranet. Web services are interoperable, reusable and follow strict standards and protocols to be followed for accessing them.

SOAP (Simple Object Access Protocol) is a specification for exchanging information between application and Web Service. Web service request and response are encoded in XML format.

This blog is to provide step-by-step instruction on invoking a web service through Datastage.

At the high level, following are the steps to be followed.

Identify and Save Web Service Definition
Import Web Service Definition
Configure Web Service Operation
Configure Web Service Request
Configure Web Service Response

Identify and Save Web Service Definition

Many web services are publicly available for free. In this example, let us try to access Country web service published through webservicex site.

Open URL http://www.webservicex.net/WS/WSDetails.aspx?WSID=17&CATID=7 in a web browser.

WSDL definition is listed on the XML frame.

If you are using Firefox,

Right click on WSDL definition frame

Select “This Frame” option from popup menu

Select “Save frame as” option to locally save the file

If you are using Internet Explorer

Click on WSDL definition frame

Select File Menu and Click Save As option to save the file locally

Import Web Service Definition

This step will help to import the WSDL file saved in previous step into Datastage

Select Web Service Function Definitions in “Import” menu.

It opens Web Services browser which lists all the definitions already available on the Datastage project

Click on “Metadata Importer” option

Click on “Open File” option and select the location of WSDL file saved earlier

Web service explorer will lists the available web service operations
Right click one of the service operation and select Import all operations

Configure Web Service Operation

Next step is to create a Server Job to access “Country” Web Service through Web Services Client Stage.

Login to Datastage Designer and Create a new Server Job
From Palette, Select Web Services Client from Real Time group
Place a sequential file stage as output

Open Web Services Client stage properties
Click on “Select Web Service Operation”

Click on “Select Web Service Operation”
Select “GetCountries” option. This web services does not have any input argument to be passed and hence Web Services Client stage is used for data retrieval.

Select “GetCountries” option and click on “Select this item” link

If the Datastage server is running behind a proxy for internet access (as most of the site does), configure proxy settings in Proxy tab

Enable HTTP/HTTPS option
Supply user name and password for accessing internet

Specify proxy host name (without http). If host name and port details are not known, its a general practice to contact Datastage Administrator to obtain such information.

If Datastage sever and Datastage client machine are directed through same internet proxy, these details can be extracted using the steps below. However, this is not recommended and demonstrated here for test purpose only.

Open Control Panel, Internet Options.

Select LAN Settings from Connections tab

Open the URL specified in LAN settings on a web browser

Host name and port details are generally specified at the “return” statement in configuration script. Supply this information in Web Services Client stage.

NOTE:

This would work only when the server is already rightly configured for internet access through proxy
Include the server details in Web Client Stage excluding the file name