Robust Session Storage in Phoenix Live View Sessions
For an internal project called ‘ControlManiac’, which helps us with all the boring numbers juggling in our software studio, I had to add a global filter to the navigation bar, which lets me select the division I want to filter the data for on whatever view I am currently on.
Since we often switch views while using this app, it should keep its selection. It should also keep it upon reloading or revisiting the page and upon deployment of a new version.
I could, of course, pursue the session approach and just make sure to add a parameter every time I switch between the main live views, but this does feel very odd.
To be able to load data via plug and on_mount, we first implement a module ControlManiacWeb.DivisionSelector and added it to the pipline:
What this module does is quite simple. It gets up the table within a GenServer, to ensure it exists when the application starts. It then offers functions to insert and get entries, which directly write into the ETS table to avoid the GenServer becoming a bottleneck.
