Refreshing dataframe source on page load

I am looking to reference a updated source file upon page refresh.

I know there is a method to update upon page load.

However, I am unable to do this as my file reference has to be in global, and cannot be inside the function serving the dynamic layout, as I need to reference the variable in the app callback.

Is it possible to update a dataframe from an Excel file upon page refresh? How else am I able to constantly retrieve the updated information from a static / unchanging file path?