[BUG] dcc.Location callback fires twice IDENTICALLY #1049

schmidt-jake · 2019-12-16T20:10:18Z

As far as I can tell, this flavor of the "duplicate dcc.Location callback" issue (#883) hasn't been documented yet. When I run a multipage app, reloading the page fires the callback twice with the same href / pathname / search payload. This is distinct from the other issue of having the callback return None and then returning the proper value(s).

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

navbar = dbc.NavbarSimple(
    brand='Frac Planning App',
    brand_href='/',
    sticky='top',
)

body = dbc.Container(
    dbc.Row(
        dbc.Col(id='page-content')
    )
)

app.layout = html.Div([
    dcc.Location(id='url', refresh=False),
    navbar,
    body
])

@app.callback(Output('page-content', 'children'),
              [Input('url', 'href')],
              [State('url', 'pathname'), State('url', 'search')])
def display_page(href, pathname, search):
    print('HREF:', href)
    print('PATHAME:', pathname)
    print('SEARCH:', search)
    url = urllib.parse.urlparse(href)
    # print('RAW pathname:', url)
    print('TRIGGER(S):', [i['prop_id'] for i in dash.callback_context.triggered])
    if url.path == '/':
        return form.layout
    elif url.path == '/result':
        query = dict(urllib.parse.parse_qsl(url.query))
        return result.plot(**query)
    else:
        raise dash.exceptions.PreventUpdate

Here is the output. It doesn't always print in the same order:

HREF: http://houmedge201:5004/
PATHAME: /
HREF: http://houmedge201:5004/
SEARCH: 
PATHAME: /
TRIGGER(S): ['url.href']
SEARCH: 
TRIGGER(S): ['url.href']

Running on Linux. Versions used:

dash                       1.7.0
dash-core-components       1.6.0
dash-html-components       1.0.2
dash-renderer              1.2.2

I've tried the fix mentioned in #883 (comment) to no avail. Solving this is mission critical for my app because the duplicate callback crashes a subsequent database query.

Changing href via a html.Link makes the callback fire only once. However, users need to be able to share app URLs with query params, which right now is broken due to this bug.

The text was updated successfully, but these errors were encountered:

schmidt-jake · 2020-01-02T17:03:26Z

Is anyone else experiencing this issue?

landert · 2020-01-03T07:37:30Z

🙋‍♂️

abogaard · 2020-01-05T09:36:51Z

Me as well

bfaivre · 2020-01-16T22:03:49Z

Same

judithbach · 2020-01-30T09:39:59Z

me too!

davidolmo · 2020-02-04T17:25:09Z

me too. I tried to avoid the second time execution by using a data_store flag but for some reason, as the states and inputs are exactly the same, this can't be accomplished

usser123 · 2020-02-11T09:25:38Z

I am experiencing the same issue. Callback with a 'pathname' property as input is being triggered 4 times. The result is that a chart on another page takes a few seconds to appear rather than appear instantly when I click on the button for that page. Critical issue.

…State in locations pathname property

jgoday · 2020-02-18T22:21:51Z

I'm experiencing this issue too.
Digging a bit in the source code, it seems a dash-renderer problem with some components default state.
Here is a quick fix to avoid this problem in Location component (jgoday@5681290).

Need to figure out why this is happening with the location component anyway, maybe the real problem resides in dash-core-components/src/components/Loading.react.js ...) 🤔

danjdo · 2020-02-21T17:32:05Z

Is anyone else experiencing this issue?

Me too.

ndepal · 2020-03-27T19:43:26Z

I'm having the same issue on dash 1.9.1.

BrunoGomesCoelho · 2020-03-31T00:57:34Z

Having the same issue here unfortunately

Samreay · 2020-03-31T02:57:59Z

Yup, I also get this, very frustrating. Its not firing twice... its a single click on a dcc.Link is firing the change callback EIGHT times. A click on the daily dashboard, ventilation and back to daily gives the following console output:

@app.callback(Output("fluidContainer", "children"), [Input("url", "pathname")])
def display_dashboard(pathname):
    print(pathname)
    return locations.get(pathname)

Gives:

/daily
/daily
/daily
/daily
/daily
/daily
/daily
/daily
/daily
/daily
/ventilation
/ventilation
/ventilation
/ventilation
/ventilation
/ventilation
/ventilation
/ventilation
/ventilation
/ventilation
/daily
/daily
/daily
/daily
/daily
/daily
/daily
/daily
/daily
/daily

pererumbo · 2020-04-07T13:00:49Z

I'm facing exactly same situation than Samreay, anyone found the root cause? I've tried with both href and pathname as input but still same behaviour..

wvwhome · 2020-04-08T19:38:30Z

I tried the first example on the documentation page: http://dash-docs.herokuapp.com/urls
On page reload, the callback runs twice. 04/10/2020: Continues with Dash v1.11.0.

wvwhome · 2020-04-17T13:09:23Z

4/17/2020: However, Dash 1.11 is a great improvement over Dash 1.10 for chained callbacks with dcc.Location. I have a program with three callbacks. For the page load with Dash 1.10 the sequence was: 3, 2, 1, 1, 3, 2, 3. With Dash 1.11 the sequence is: 1, 1, 2, 3. So much better. I have a dozen other programs with similar improvements.
9/3/2020: Dash 1.16 fixes most of theses issues for my programs -- major improvement.

rafaelqntn · 2020-05-01T02:59:55Z

Same here.
I am going to watch this issue.

Thank you for the awesome job with Dash, by the way.

tjmcdono · 2020-05-01T08:49:56Z

Yes please

…

On Thu, Apr 30, 2020, 11:00 PM Rafael Quintana ***@***.***> wrote: Same here. I am going to watch this issue. Thank you for the awesome job with Dash, by the way. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#1049 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABKCM2O5N5XTKYNRGC5ZWVLRPI3MHANCNFSM4J3PPKIQ> .

hcai · 2020-06-01T23:21:32Z

same here

ghost · 2020-06-16T01:42:11Z

any updates here? I am currently building a tool based on dash and I have a long process which is triggered by a callback - unfortunately this callback is triggered twice: so now I have to wait extra long for the output

rusiano · 2020-06-16T14:25:51Z

+1

pkstacey · 2020-08-21T16:40:03Z

Same issue here, when reading a cookie :/ waste of time and resource. Wondering if this is on the official fixit list for Plotly...

grahamegee · 2020-11-01T14:42:29Z

I thought I had a workaround using an lru_cache, but it actually doesn't help that much, as the handler gets called multiple times before the first response gets returned.

to combat plotly/dash#1049

Hootie9lives · 2021-04-16T03:40:04Z

+1

Paulito123 · 2021-05-22T13:32:52Z

Having the same problem, no fix for this?

TashaStenner · 2021-11-03T15:05:15Z

Is there any fix? Or a workaround for this available?

Stayermax · 2022-05-25T13:06:52Z

I'm still having this issue with dash 2.3.1, did anybody find working solution?

Samreay · 2022-05-25T13:27:57Z

@alexcjohnson @T4rk1n sorry for the personal tag, but thought it might be useful to make sure that this issue has some more visibility and is on the roadmap.

I assume its been buried in the backlog in the last two years, but seems like its still an issue for many users.

luggie · 2022-10-17T13:38:03Z

Still present in dash 2.6.1 :(

Samreay · 2022-10-17T23:16:05Z

Thankfully there's streamlit instead now to develop in. How can it be three years, a javascript fix posted, and direct dev tags, but not even a comment from any of the core team?

ned2 · 2022-10-20T16:05:07Z

Hey @Samreay, @luggie, or @Stayermax, do you have a minimal reproducible example of a Dash app that exhibits the Location callback firing twice?

Looking back through the history of the issue, I can't actually find any code that can be used to reproduce the issue, which makes triage/diagnosis of the problem difficult. There are likely other possible causes of duplicate callbacks firing based on custom code/env setup, which would need to be eliminated from possibility.

I had a a go at creating a minimal reproducible example from the original post (which itself was not reproducible), but don't see the behaviour. Do you in your setup? or does the example need to be changed?

from dash import Dash, html, dcc, Input, State, Output

app = Dash(__name__)

app.layout = html.Div([html.Div(id="page-content"), dcc.Location(id="url")])


@app.callback(
    Output("page-content", "children"),
    Input("url", "href"),
    State("url", "pathname"),
    State("url", "search"),
)
def display_page(href, pathname, search):
    print("HREF:", href)
    print("PATHAME:", pathname)
    print("SEARCH:", search)
    if pathname == "/":
        return html.Div(f"HOME - Search: {search}")
    return html.Div(f"{pathname} - Search: {search}")


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

Samreay · 2022-10-21T03:39:53Z

Apologies mate, I'm now in a different role at a different company, so don't have access to the source to try and create a minimal example.

serensoner · 2022-10-23T12:37:22Z

Hey @Samreay, @luggie, or @Stayermax, do you have a minimal reproducible example of a Dash app that exhibits the Location callback firing twice?

Looking back through the history of the issue, I can't actually find any code that can be used to reproduce the issue, which makes triage/diagnosis of the problem difficult. There are likely other possible causes of duplicate callbacks firing based on custom code/env setup, which would need to be eliminated from possibility.

I had a a go at creating a minimal reproducible example from the original post (which itself was not reproducible), but don't see the behaviour. Do you in your setup? or does the example need to be changed?
from dash import Dash, html, dcc, Input, State, Output

app = Dash(__name__)

app.layout = html.Div([html.Div(id="page-content"), dcc.Location(id="url")])


@app.callback(
    Output("page-content", "children"),
    Input("url", "href"),
    State("url", "pathname"),
    State("url", "search"),
)
def display_page(href, pathname, search):
    print("HREF:", href)
    print("PATHAME:", pathname)
    print("SEARCH:", search)
    if pathname == "/":
        return html.Div(f"HOME - Search: {search}")
    return html.Div(f"{pathname} - Search: {search}")


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

It's been a while since I worked on dash, but I created a minimal repro, but unfortunately only in the older versions:

dash==1.9.0
dash-renderer==1.7.0
Flask==2.0.0
Jinja2==3.0.3
markupsafe==2.1.1
werkzeug==2.0.0
itsdangerous==0.24

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

app = dash.Dash()

app.layout = html.Div([
    dcc.Location(id='url', refresh=False),
    html.Div(id='content'),
])

@app.callback(Output('content', 'children'),
              [Input('url', 'pathname')])
def display_page(pathname):
    print(f'you are now at: {pathname}')
    return pathname

app.run_server(host='0.0.0.0', debug=True)

Stayermax · 2022-10-23T12:40:34Z

Sorry, I also don’t have the code. From: serensoner ***@***.***> Date: Sunday, 23 October 2022 at 15:37 To: plotly/dash ***@***.***> Cc: Pankratov Vitaly ***@***.***>, Mention ***@***.***> Subject: Re: [plotly/dash] [BUG] dcc.Location callback fires twice IDENTICALLY (#1049) Hey @Samreay<https://github.com/Samreay>, @luggie<https://github.com/luggie>, or @Stayermax<https://github.com/Stayermax>, do you have a minimal reproducible example of a Dash app that exhibits the Location callback firing twice? Looking back through the history of the issue, I can't actually find any code that can be used to reproduce the issue, which makes triage/diagnosis of the problem difficult. There are likely other possible causes of duplicate callbacks firing based on custom code/env setup, which would need to be eliminated from possibility. I had a a go at creating a minimal reproducible example from the original post (which itself was not reproducible), but don't see the behaviour. Do you in your setup? or does the example need to be changed? from dash import Dash, html, dcc, Input, State, Output app = Dash(__name__) app.layout = html.Div([html.Div(id="page-content"), dcc.Location(id="url")]) @app.callback( Output("page-content", "children"), Input("url", "href"), State("url", "pathname"), State("url", "search"), ) def display_page(href, pathname, search): print("HREF:", href) print("PATHAME:", pathname) print("SEARCH:", search) if pathname == "/": return html.Div(f"HOME - Search: {search}") return html.Div(f"{pathname} - Search: {search}") if __name__ == "__main__": app.run_server(debug=True) It's been a while since I worked on dash, but I created a minimal repro, but unfortunately only in the older versions: requirements.txt dash==1.9.0 dash-renderer==1.7.0 Flask==2.0.0 Jinja2==3.0.3 markupsafe==2.1.1 werkzeug==2.0.0 itsdangerous==0.24 `main.py `import dash_core_components as dcc import dash_html_components as html from dash.dependencies import Input, Output import dash app = dash.Dash() app.layout = html.Div([ dcc.Location(id='url', refresh=False), html.Div(id='content'), ]) @app.callback(Output('content', 'children'), [Input('url', 'pathname')]) def display_page(pathname): print(f'you are now at: {pathname}') return pathname app.run_server(host='0.0.0.0', debug=True) ` — Reply to this email directly, view it on GitHub<#1049 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/AJFOCUG3AZ4CUNEQAXUNXBDWEUWQ7ANCNFSM4J3PPKIQ>. You are receiving this because you were mentioned.Message ID: ***@***.***>

ned2 · 2022-11-03T13:13:51Z

Thanks heaps @serensoner! I can confirm that your example has duplicate callback invocations, when run with Dash 1.9. However not on the most recent Dash, where there's only one callback invocation. Bisecting suggests that this bug was actually fixed in Dash 1.16.... which was released September 4 2020, interestingly, about the time you were speculating @alexcjohnson that this bug could have been fixed: plotly/dash-core-components#858 (comment)

@alexcjohnson, given we can't identify a reproducible example showing this bug in the latest Dash, maybe this issue should be closed? If someone is able to come up with an example showing it's still there, might be better to start with a fresh issue.

alexcjohnson · 2022-11-04T17:26:55Z

@ned2 thanks for digging into this. Good to know at least some of these cases have been fixed! @luggie any chance you can post an app showing the problem you're still seeing? We really need a reproduction case in order to get to the bottom of this. After plotly/dash-core-components#858 (comment) I seem to have felt we had more to do:

The boundaries of the problem have changed a little, as evidenced by this test, but it’s definitely not fixed.

but my comment may just have been based on the preceding comment by @astrowonk rather than having seen the problem myself.

astrowonk · 2022-11-04T17:32:07Z

@ned2 thanks for digging into this. Good to know at least some of these cases have been fixed! @luggie any chance you can post an app showing the problem you're still seeing? We really need a reproduction case in order to get to the bottom of this. After plotly/dash-core-components#858 (comment) I seem to have felt we had more to do:

The boundaries of the problem have changed a little, as evidenced by this test, but it’s definitely not fixed.

but my comment may just have been based on the preceding comment by @astrowonk rather than having seen the problem myself.

It's worth noting that whatever I was experiencing was unrelated to this issue. My old comment on the other issue/PR was inaccurate. I am not aware of this issue affecting anything I'm doing at the moment.

schmidt-jake added the dash-type-bug label Dec 16, 2019

schmidt-jake changed the title ~~[BUG] dcc.Location callback fires twice IDENTICALLY~~ [BUG] dcc.Location callback fires twice IDENTICALLY when reload=False Dec 16, 2019

schmidt-jake changed the title ~~[BUG] dcc.Location callback fires twice IDENTICALLY when reload=False~~ [BUG] dcc.Location callback fires twice IDENTICALLY Dec 16, 2019

jgoday added a commit to jgoday/dash that referenced this issue Feb 18, 2020

plotly#1049: dcc.Location callback fires twice, do not triggerDefault…

5681290

…State in locations pathname property

tonio73 mentioned this issue Apr 16, 2020

Workaround double load of each URL path tonio73/dnnviewer#35

Closed

tonio73 mentioned this issue Apr 17, 2020

Remove workaround and check Dash solution to bouncing URL path change tonio73/dnnviewer#38

Closed

chriddyp mentioned this issue Aug 27, 2020

[BUG] Concurrent callbacks broken in Dash 1.13+? #1350

Closed

alexcjohnson mentioned this issue Sep 3, 2020

Plotly.js 1.55.1 plotly/dash-core-components#858

Merged

FRYoussef mentioned this issue Sep 11, 2020

Unable to create multipage apps Grasia/dao-analyzer#15

Closed

grahamegee pushed a commit to limejump/agile-insights that referenced this issue Dec 2, 2020

put an in memory cache on the metrics view

e1d5baf

to combat plotly/dash#1049

ned2 mentioned this issue Nov 5, 2022

[BUG] Callback with dcc.Location 'search' input is fired 2 times #883

Closed

[BUG] dcc.Location callback fires twice IDENTICALLY #1049

[BUG] dcc.Location callback fires twice IDENTICALLY #1049

Comments

schmidt-jake commented Dec 16, 2019 • edited Loading

schmidt-jake commented Jan 2, 2020

landert commented Jan 3, 2020

abogaard commented Jan 5, 2020

bfaivre commented Jan 16, 2020

judithbach commented Jan 30, 2020

davidolmo commented Feb 4, 2020 • edited Loading

usser123 commented Feb 11, 2020

jgoday commented Feb 18, 2020 • edited Loading

danjdo commented Feb 21, 2020

ndepal commented Mar 27, 2020

BrunoGomesCoelho commented Mar 31, 2020

Samreay commented Mar 31, 2020 • edited Loading

pererumbo commented Apr 7, 2020

wvwhome commented Apr 8, 2020 • edited Loading

wvwhome commented Apr 17, 2020 • edited Loading

rafaelqntn commented May 1, 2020

tjmcdono commented May 1, 2020 via email

hcai commented Jun 1, 2020

ghost commented Jun 16, 2020

rusiano commented Jun 16, 2020 • edited Loading

pkstacey commented Aug 21, 2020

grahamegee commented Nov 1, 2020

Hootie9lives commented Apr 16, 2021

Paulito123 commented May 22, 2021

TashaStenner commented Nov 3, 2021

Stayermax commented May 25, 2022

Samreay commented May 25, 2022

luggie commented Oct 17, 2022

Samreay commented Oct 17, 2022

ned2 commented Oct 20, 2022 • edited Loading

Samreay commented Oct 21, 2022

serensoner commented Oct 23, 2022 • edited Loading

Stayermax commented Oct 23, 2022 via email

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