you probably is looking for an event base trigger to start the data refresh task. You can do it basically using the API with a simple REST call (eg. http://help.qlik.com/en-US/sense-developer/3.2/Subsystems/RepositoryServiceAPI/Content/RepositoryServiceAPI/RepositoryServiceAPI-Task-Start-Task.htm)
You can also rely on a Console Line Interface like this Qlik Branch.
Keep in mind, Qlik is intendet to work on consolidated data and does not on the real time stream data.