Hi, im trying to get my head around developing this and want to hear your thoughts before i go ahead.
I have a site that receives data via HTTP post and stores this in a mySQL DB. There is a then a web frontend that allows users to to look at the data, and trend it in a graph.
What i want to add, is a way so that a user can Add simple calculations to the data when looking at it. So a user may want to add a multiplication factor to a "column" of a data, so that when the data is viewed in the graph, its got the caluclation applied to it. So thats a simple calcuation and i could easily have that as a simple "multiply by this option" but the calcs might be a bit more complex and so i thought it would be good to allow the user to basically write a simple peice of code and apply it to the data. This is the bit im stuck with?
I thought at first i could have the data always run though a function in a php file, then allow that function to be edited and saved. But im sure this opens alot of "safety alerts" as essentially its giving access to write, store and execute PHP script, which isnt good.
Any thoughts on the best way to do this?