NavLink would not trigger Input('url', 'pathname')

[eromoe]

Hello,

Refer to dash exmaple, click dcc.Link would trigger Input('url', 'pathname') callback .

external_stylesheets = ['https://codepen.io/chriddyp/pen/bWLwgP.css']
app = dash.Dash(__name__, external_stylesheets=external_stylesheets)

app.layout = html.Div([
    dcc.Location(id='url', refresh=False),
    dcc.Link('head', href='/'),
    html.Br(),
    dcc.Link('order_source', href='/order_source'),
    html.Div(id='page-content')
])


@app.callback(Output('page-content', 'children'),
              [Input('url', 'pathname')])
def display_page(pathname):
    print('Enter : %s' % pathname)
    if pathname == '/order_source':
         return order_source_statistics.layout
    elif pathname == '/apps/app2':
         return app2.layout
    else:
        return 'something'

But this doesn't work in dbc.NavLink('order_source', href='/order_source') .

external_stylesheets = [dbc.themes.BOOTSTRAP]
app = dash.Dash(__name__, external_stylesheets=external_stylesheets)

navbar = dbc.NavbarSimple(
    children=[
        dbc.NavItem(dbc.NavLink("aaaa", href="/")),
        dbc.NavItem(dbc.NavLink("order_source", href="/order_source")),
    ],
    brand="Demo",
    brand_href="#",
    sticky="top",
)

....

app.layout = html.Div([
    navbar,
    body
])

[tcbegley]

Hi @eromoe, thanks for reporting

I wasn't able to reproduce this. Here is the code I ran based on your snippets. Could you try running this and verify that you get the same problem? (I am returning strings from the callback so that I don't have to define order_source_statistics.layout etc.)

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

external_stylesheets = [dbc.themes.BOOTSTRAP]
app = dash.Dash(__name__, external_stylesheets=external_stylesheets)

navbar = dbc.NavbarSimple(
    children=[
        dbc.NavItem(dbc.NavLink("aaaa", href="/")),
        dbc.NavItem(dbc.NavLink("order_source", href="/order_source")),
    ],
    brand="Demo",
    brand_href="#",
    sticky="top",
)

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


@app.callback(Output("page-content", "children"), [Input("url", "pathname")])
def display_page(pathname):
    print("Enter : %s" % pathname)
    if pathname == "/order_source":
        return "order_source_statistics.layout"
    elif pathname == "/apps/app2":
        return "app2.layout"
    else:
        return "something"


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

[eromoe]

@tcbegley Thank you ! I found it need dcc.Location(id="url", refresh=False) . I think this should be introduced in the docs.

[tcbegley]

Great! Glad I could help. And thanks for the feedback, I'll make a note to include it when we next refresh the documentation.