I am using same logic for Observations, OBS. 

Expression val = ##class(CUSTOM.Transformation.Observation).GetObsItems(val)

In my transformation classMethod. I am able to get the PatientID :  $get(%request.Data("PatientID",1)) 

But not able to get the RowId. to find the streamlet id. 

Please let me know how to get the RowID for OBS.

Thank you 

@Hoi Lai , I am trying to achieve something similiar to you i guess, I have a application in Vuejs, hosted on IRIS, using a web application, I am looking to create a login page on over it, which uses a basic HealthShare login credentials to log in the user. 

Can you please let me know, Is there something needs to be done on the frontend side as well. or is there an option to somehow use the basic healtshare login page which comes on opening the Management portal.