How to save variable for every user in dash to use it in callback initialization?

Dash Python
1

I’m trying to build dashboard that can dynamically update my model and I’m trying to make it multiuser, so users can concurrently see different models So far I used dcc.Store(storage_type=‘session’) inside my code, but I don’t know how to make variables for every user that i can “unpack” inside callback initiation if i need dynamic number of graphics for every user that depends on number of features so I need a way to do something like this

@app.callback(Output('graph','children'),
              [Input('object_{}'.format(i), 'value') for i in range(<var_for_user>)])
...

what should i user instead of ‘var_for_user’?

2

The Store exists clientside, i.e. the is one for each user already. Hence the app should would for multiple users independently without any modifications.

3

Thank you for response!

But if i have different number of graphs for every user, for example, and i need to pass it all into callback Input, how can i manage to do so?

4

So, just to be clear, what you want is to pass information from one session (i.e. user) to another?

5

No, nothing like that
Sorry if i put it wrong
Lets suggest that my user uploads config file
I parse it into dcc.Store component and build x sliders( number x i got from this file)
so now i have x sliders. If user uploads new config with number y, then i want to rebuild dashboard for him and then i’ll have y slider
Question is:
how can i build my callback, if i dont know how many sliders i have?
I thought i should make something like

@app.callback(Output(..),
             [Input('slider_{}'.format(i) for i in range(<number in loaded file>)])

How can i do this?

6

Ah, then you are probably looking for pattern matching callbacks,

7

thanks a lot!

can i ask you one more thing?

if i want to use

dbc.Input(id='some-id', type='file')

how should i use in callback?
I tried some options:

Input('some-id', 'data') #returns NoneType object
Input('some-id', 'contents') #same

I dont understand what should i use to load my file

Thanks!