Refresh dropdown on page reload

Dash Python
1

My app populates a dropdown from a database. The list of values changes very occasionally and I’d like to reload the values when the page is refreshed. I’m using a multi-page app but a simplistic example is

import dash
from dash import html, dcc

app = dash.Dash(__name__)

def get_items():
    print('updating items')
    return [{'label': 'foo', 'value': 'foo'}]

app.layout = html.Div(
    children=[dcc.Dropdown(id='my-dropdown', options=get_items())]
)

if __name__ == '__main__':
    app.run_server(debug=True)

The get_items helper only gets called once, I’d like to somehow trigger on page reload - is there a callback I can use for this?

2

I figured it out myself, I need to pass a callable to app.layout

import dash
from dash import html, dcc

app = dash.Dash(__name__)

def get_items():
    print('updating items')
    return [{'label': 'foo', 'value': 'foo'}]

def app_layout():
    return html.Div(
        children=[dcc.Dropdown(id='my-dropdown', options=get_items())]
    )

app.layout = app_layout

if __name__ == '__main__':
    app.run_server(debug=True)