Sorry if I'm not being clear and thanks for your help.
I have a feature class. It is published as a feature service. I want to edit this feature service with a web app (3rd party, little ability to customize).
The feature class is also consumed by desktop apps, arcgis and 3rd party.
I do not wish to apply a class extension to the feature class as I do not wish to install the necessary .dlls to the desktops of users who are using the feature class directly. Also not sure how it would react with 3rd party apps.
I wish to use an SOE on the feature service to automate certain business logic for the add features operation of the feature service.
Do you, or anybody, know if this is possible?
For clarity: I know I can add another operation to the feature service to do this but my web app would then have to make an extra call to this operation. Instead I want it to be executed automatically when a new feature is created.