title: R shiny: How to allow users to stop the process? And how to stop the app from backend?
body: <p>I have a shiny app that allows users to upload their own data and do a few tasks. Depending on their data size and the type of tasks they would want to perform, sometimes the process gets long and even lasting forever. I would like to add the "stop" function in which users can click on it and the current task will stop and they can continue to some other tasks. How should I do it?</p>
  
  <p>My second question is related to the first one. Say one of my app users has deployed a very heavy process and it has heavily occupied my CPU but the user himself has not initiated the stop signal. I would like to impose a "time out" command so that the app will be automatically terminated say after 5 minutes. How can I set it up?</p>
  
  <p>Many thanks and best regards,</p>
  
  <p>cloudy</p>