Disable "Submit" button for 30 seconds in Python + Dash

Question

I want to stop the user from pressing the "Submit" button for 30 seconds, after they have pushed it in the script below. How would I go about doing this? This is how my code looks currently:

import dash
from dash.dependencies import Input, Output, State
import dash_core_components as dcc
import dash_html_components as html

app = dash.Dash()

app.layout = html.Div([
    dcc.Input(id='my-id', value='initial value', type="text"),
    html.Button('Submit', id='button'),
    html.Div(id='my-div')
])

@app.callback(
    Output(component_id='my-div', component_property='children'),
    [Input('button', 'n_clicks')],
    state=[State(component_id='my-id', component_property='value')]
)
def update_output_div(n_clicks, input_value):
    return 'You\'ve entered "{}" and clicked {} times'.format(input_value, n_clicks)

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

Does anyone know how I can stop users from pushing the button for 30 seconds?

Thank in advance.

EDIT 15/08/2018 9:30AM GMT RESPONSE TO stevepastelan:

import dash
from dash.dependencies import Input, Output, State
import dash_core_components as dcc
import dash_html_components as html

app = dash.Dash()

app.layout = html.Div([
    dcc.Input(id='my-id', value='initial value', type="text"),
    html.Button('Submit', id='button'),
    html.Div([dcc.Interval(
        id='interval-component',
        interval=1 * 3000,  # in milliseconds
        n_intervals=0
)]),
    html.Div(id='my-div')
])

@app.callback(
    Output(component_id='my-div', component_property='children'),
    [Input('button', 'n_clicks')], [Input('interval-component', 'n_intervals')],
    state=[State(component_id='my-id', component_property='value')]
)
def update_output_div(n_clicks,n_intervals, input_value):
    return 'You\'ve entered "{}" and clicked {} times'.format(input_value, n_clicks)

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

EDIT 15/08/2018 16:22PM WROTE SIMPLER SCRIPT WITH THE AN EDITED CALLBACK BUT IT DOESNT WORK:

import dash
from dash.dependencies import Input, Output, State
import dash_core_components as dcc
import dash_html_components as html

app = dash.Dash()

app.layout = html.Div([
    dcc.Input(id='my-id', value='initial value', type="text"),
    html.Button('Submit', id='button'),
    html.Div([dcc.Interval(
        id='interval-component',
        interval=1 * 3000,  # in milliseconds
        n_intervals=0
)]),
    html.Div(id='my-div')
])

@app.callback(
    Output(component_id='my-div', component_property='children'),
    [Input('button', 'n_clicks')], [Input('interval-component', 'n_intervals')],
    state=[State(component_id='my-id', component_property='value')]
)

def update_output_div(n_clicks,n_intervals, input_value):
    return 'You\'ve entered "{}" and clicked {} times'.format(input_value, n_clicks)

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

Answer 1

Updated answer

Okay, I managed to implement my own suggestion, but it was not trivial and still has quirks.

Complicating factors were:

• Dash does not permit two callbacks to target the same Output
• There is no good way to track which Input or Event triggered your callback. Workarounds generally involve tracking the number of clicks per button (see https://github.com/plotly/dash-html-components/pull/37 as an example).
• Disabling a timer via disable=True or max_requests=0 appears to be permanent. Once I stopped a timer in this way, I could not restart it with either disable=False or max_requests=1000.

Issues:

• In this solution, update_output_div() gets called twice -- but you can tell the difference between the two by measuring the number of button clicks to the previous count, so you can keep it from submitting your data twice.
• Timeouts of less than 100ms won't work. I had to split the delay timer for my method to work, so I chose 100 and (1000 * BUTTON_PRESS_LOCKOUT_SECONDS)-100 as the two timer durations. In principle, you could split them evenly half and half. I don't know if there are any problems with using a low timeout when working over the network (I did my testing on localhost).

Inspiration drawn from:

• https://community.plot.ly/t/how-to-turn-off-interval-event/5565/3
• https://github.com/plotly/dash-recipes/blob/master/toggle-interval.py

import json
import datetime

import dash
from dash.dependencies import Input, Output, State, Event
import dash_core_components as dcc
import dash_html_components as html

BUTTON_PRESS_LOCKOUT_SECONDS = 10  # seconds

app = dash.Dash()
app.config['suppress_callback_exceptions']=True

def serve_layout():
    return html.Div([
        dcc.Input(id='my-id', value='initial value', type="text"),
        html.Button('Submit', id='button'),
        html.Div(
              [
                  dcc.Interval(id='interval-component', disabled=True)
                , dcc.Interval(id='interval-sync-component', disabled=True)
              ]
            , id='interval-container'
        ),
        html.Div("", id='my-div'),
        html.Div(json.dumps({'n_clicks':0, 'n_previous_clicks':0}), id='local_data'),
        html.Div('??', id='button-status'),
    ])

app.layout = serve_layout

# Track button clicks
@app.callback(
    output=Output(component_id='local_data', component_property='children'),
    inputs=[Input('button', 'n_clicks')],
    state=[State('local_data', 'children')],
    events=[Event('interval-sync-component', 'interval')]
)
def track_clicks(n_clicks, local_data_json):
    if n_clicks is None:
        n_clicks = 0

    local_data = json.loads(local_data_json)
    n_previous_clicks = local_data['n_clicks']

    # Update local data with the new click data
    local_data.update(**{'n_clicks': n_clicks, 'n_previous_clicks': n_previous_clicks})
    # local_data.update(**{'n_clicks': n_clicks, 'n_previous_clicks': n_previous_clicks})
    return json.dumps(local_data)


# When the button click count is updated, submit
@app.callback(
    output=Output(component_id='my-div', component_property='children'),
    inputs=[Input('local_data', 'children')],
    state=[State(component_id='my-id', component_property='value'), State('my-div', 'children')]
)
def update_output_div(local_data_json, input_value, current_state):
    local_data = json.loads(local_data_json)
    n_clicks = local_data['n_clicks']
    n_previous_clicks = local_data['n_previous_clicks']

    # Real submit
    if n_clicks > n_previous_clicks:
        return 'You\'ve entered "{}" and clicked {} times ({})'.format(
              input_value
            , n_clicks if n_clicks is not None else 0
            , datetime.datetime.now()
        )

    # Not a real submit, but function is called an extra time as a side effect of the timer nonsense below.
    else:
        return '*' + current_state


# Start (or stop) the timer
@app.callback(
    output=Output('interval-container', 'children'),
    inputs=[Input('local_data', 'children')],
    state=[State('button', 'disabled')],
    events=[Event('interval-component', 'interval')]
)
def start_timer(local_data_json, button_is_disabled):
    local_data = json.loads(local_data_json)
    n_clicks = local_data['n_clicks']
    n_previous_clicks = local_data['n_previous_clicks']

    children=[]

    if n_clicks > n_previous_clicks:
        sync_timer = dcc.Interval(
            id='interval-sync-component',
            interval=100,  # in milliseconds
        )
        children.append(sync_timer)

    if button_is_disabled:
        main_timer = dcc.Interval(
            id='interval-component',
            interval=(1000 * BUTTON_PRESS_LOCKOUT_SECONDS)-100,  # in milliseconds
        )
        children.append(main_timer)

    return children


# Enable the button whenever the timer interval is triggered or disable it when the button is pressed
@app.callback(
    output=Output('button', 'disabled'),
    inputs=[Input('button', 'n_clicks')],
    state=[State('local_data', 'children')],
    events=[Event('interval-component', 'interval')]
)
def toggle_button_disabled_state(n_clicks, local_data_json):
    local_data = json.loads(local_data_json)
    # n_clicks = local_data['n_clicks']
    if n_clicks is None:
        n_clicks = 0
    n_previous_clicks = local_data['n_previous_clicks']

    # We got here via button click, so disable the button
    if n_clicks > n_previous_clicks:
        return True

    # We got here via timer expiration, so enable the button
    else:
        return False  # enable the button

# Report on the button status
@app.callback(
    output=Output('button-status', 'children'),
    inputs=[Input('button', 'disabled')]
)
def update_button_status(disabled):
    if disabled:
        return 'Disabled submit button for {} seconds'.format(BUTTON_PRESS_LOCKOUT_SECONDS)
    else:
        return 'Submit button enabled'


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

Original answer

You can trigger actions to be taken on the page based on a timer using dash_core_components.Interval. There are some examples here: https://dash.plot.ly/live-updates

You could initialize your interval component with n_intervals = 0, and then make your submit button disable itself and set n_intervals = 1. Then write a callback on the interval that re-enables the button.