Dear Experts, How can we call an external web service in  a IVIG workflow using a script node, Basic requirement is like to call a web service (a REST) with the current user name and get the approval matrix (multiple approvers defined at  the source) and use them in the workflow. (for approval, notifications and escalations  etc )

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Supun Munasinghe
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In general I would not recommend to do outbound calls from the workflows - in my experience this is the source for all kind of stability problems and dependencies that are difficult to make run stable in the real world....

That said - here is a couple ways to do it technically : 

1. As the workflow engine has full access to all underlying WAS and Java APIs you can simply script the calls using the Java APIs - but be aware that exposing APIs through the scriptframework.properties also makes the API available in all ISVG scripts which may be a security problem. This is a quick way to test feasibility of the solution. 
2. Develop a JavaScript or Workflow Extension that wraps the REST calls - this allows for easier reuse and better security (workflow extension as it can only be used in workflows) - but this comes with some development and design effort that should not be underestimated.
3. Externalize the WS calls using tooling like this SDI Workflow Extension IBM Tivoli Directory Integrator Proxy Workflow extension for IBM Security Identity Manager - this makes it possible to use much more rich frameworks and also makes it easier to return data to the workflow (I designed this many years ago but I never succeeded to have it included in ISIM/ISVG/IVIG) 

There is a couple of consideration when doing this kind of integration - you should not try to make the REST call synchronous IMHO - this will make your life miserably if the REST service is not answering - making it asynchronous is of course against its nature - so you need to include all the necessary stuff to handle errors/timeout etc. to ensure you do not block the workflow engine if the REST service is malfunctioning - and just a warning - this is very difficult to test....

HTH

NB. Just as a historical note - the ISPIM 2.0 product withdrawn many years ago had a builtin workflow extension that would probably fit your needs - I have made our Product Manager aware of this but I doubt that this will come back into IVIG anytime soon... 

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Franz Wolfhagen
WW IAM Solution Architect - Certified Consulting IT Specialist
IBM Expert Labs
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