Improve Live-mode #7
Description
Problem
At the moment every few seconds there is a request made to the server which will look up the necessary data in the database.
This causes a relatively (and unnecessary) big CPU load on the server.
Solution
It should be made that the initial request triggers a database lookup (current implementation).
Then the device will register itself as 'online' and whenever data is written to the database all connected devices that are 'online' will receive the data immediately.
A request for a database lookup (from the client to the server) is only necessary when the client (re)connects to the server.
Additional improvements/ideas
This would make is possible to have the live mode always on.
The displayed graph could autoscroll even if there is no new data available.
The graphs should still be pausable. But only for the displayed graph. Data should still be received. (Or maybe treat a live-view toggle as a reconnect to get newest data from the database?)