Don’t know if it helps and i am trying to keep it short…

I build an Oiltank measurement system with another raspberry pi.
The results will be written to a mysql database and to a JSON file, which will be uploaded to my NAS.
On the NAS i run the database and a web server.
To Display the results on a webpage i used this php script: https://github.com/cruunnerr/OilTank-Graph-WebPage

To display the results on my MM i got some very much help from our user @doubleT
He wrote this module for me: https://github.com/cruunnerr/MMM-Oiltank
The module grabs the data from a JSON file and shows it on the MM.

Maybe this could help :/

MagicMirror:

1_1522492360079_Bildschirmfoto 2018-03-31 um 12.30.56.png

Web Page:

0_1522492360077_Bildschirmfoto 2018-03-31 um 12.30.12.png