Hi Davide, unfortunately it is not possible to do this server-side. Kinvey's service is not involved in the upload itself, so we don't know when it finishes, however you can have the client trigger the server code as you mentioned.
about 10 years ago
Thanks Ivan, okay... I'll go for the client then.
Actually, since what I have to do is to call an app engine service to process the uploaded file, I'll try to see if there's a way to handle things from there... maybe with a timeout function trying a few retries till the file is fully uploaded, and the processing it.
Not a very elegant solution :D I'll think more into this.