Ok so, I know you’re thinking “why would you ever wanna do that”, but bear with me for a moment.
I made a web abb that allows users to upload a CSV file, and then takes them to a dashboard that shows some interactive plots.
The app structure is, very simplified, like this:
index.py views/ data/ upload_file.py dashboard.py
The index file imports both views at the beginning.
Upload_file.py can have two behaviors, based on a condition: it checks if the data folder contains a compatible file. If it does, it asks the user if they want to continue with the old file or upload a new one. So far so good.
If the data folder is empty, however, it asks the user to upload a file. This is where the problem starts: if data is empty, when
dashboard.py gets imported at startup, it runs its code, sees that there’s no data, and returns an error because it can’t load any dataset, of course.
So I tried importing
dashboard.py in the callback that loads the dashboard, in pseudocode like this:
@app.callback( Output(main_Div), Input(url) ) def load_dashboard(url): if url == '/dashboard': from views import dashboard return dashboard.layout
This technically works, except for one single issue: the callbacks of
dashboard.py don’t get loaded in the app, and therefore when the dashboard gets loaded, all plots are empty because there’s no callback to update them.
Surprisingly, clicking reload on the browser then makes it so that all callbacks get imported and the dashboard loads its plots properly.
I haven’t figured out a solution or a workaround yet, except making every single callback in
dashboard.py a function, as well as the callbacks of its own submodules, and run them within
index.py, but that’s such a dirty solution and I’d rather find something more elegant.
Any help or info is very much appreciated.