AttributeError: ('Read-only: can only be set in the Dash constructor or during init_app()', 'requests_pathname_prefix')

Dash Python
1

Hi,

When I run my script, I am obtaining “AttributeError: (‘Read-only: can only be set in the Dash constructor or during init_app()’, ‘requests_pathname_prefix’)”.

Can anyone help?

Thank you

2

Hi @Oladayo

How are you setting the requests_pathname_prefix ?

You can get that error if it’s not inside the Dash constructor like this:

app= dash.Dash(__name__,  requests_pathname_prefix= "/abc/123")
4

Hi @AnnMarieW ,

I don’t have requests_pathname_prefix in my script.

app = JupyterDash(name,external_stylesheets=[dbc.themes.DARKLY])

There is double underscore before ‘name’ It’s getting formatted into bold in my reply.

5

Hmm, I haven’t used JupyterDash, so if anyone else knows the answer, please jump in.

Is it just with this script, or is it with everthing?

6

everything actually. Even those script that has run successfully previously.

7

Seems some people are experiencing same issues as seen on stack overflow;

8

@Oladayo - It looks like a problem with the latest release. For now, could you please try to use the previous version?

pip install dash==2.0.0

I just noticed this has already been reported - you can track the progress on Github: Dash does not properly work with library called jupyter_dash [BUG] · Issue #1907 · plotly/dash · GitHub

1 Like
9

Yep…

I did the

pip install dash==2.0.0

Then changed

app = JupyterDash( name ,external_stylesheets=[dbc.themes.DARKLY])

to

app = dash.Dash(name,external_stylesheets=[dbc.themes.DARKLY])

some script are running fine for now.

10

Ok, but if you are using app=dash.Dash(...) then dash==2.0.1 will work fine.

It’s just a problem with JupyterDash and the latest release. Note - this issue is being worked on now, so I expect there will be fix soon.

2 Likes
11

@AnnMarieW

thank you for your help

1 Like
12

working fine now.

It seems they fixed it.

1 Like
13

@Oladayo I’m still facing the same issue though. Did you downgrade Dash to < 2.1.0 for it to work again?

14

hi,

I initially downgrade to dash==2.0.0 and changed the

app=JupyterDash() to

app=dash.Dash(),

some script ran fine while some didn’t.

After a while, I just re-installed jupyter_dash and dash without specifying the version and then it worked fine.

15

Hi…

They fixed the issue

2 Likes