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Status: Multi-Page Dash App Plugin

The pages functionality is now part of dash 2.5! These docs remain here for legacy purposes. pages is a plugin to simplify creating multi-page Dash apps.

See the community announcement for details and discussion

Multi-Page Dash App Plugin Examples

Please see Chapter 08-MultiPageDashApp for an introduction to the Multi-Page Dash App Plugin

If you would like to add an example, feel free to create a pull request!

Example: Nested Folders

This example shows how dl.plugins.register_page handles

  • Using Nested folders in pages/
  • Storing icons as arbitrary keyword arguments

See the code in /demos/multi-page-nested-folders

In larger multi-page apps it's common to organize topics into categories. Each category may have its own folder with multiple pages. This plugin automatically searches all subdirectories in pages/ and includes all the apps. In our example the heatmaps.py is in pages/ and pie-chart.py is in pages/chapter/. The dash.page_registry dictionary will include the subdirectory name(s) in the dict key and the module and path like this:

OrderedDict([
    ('pages.heatmaps', {
        'module': 'pages.heatmap', 
        'path': '/heatmap',
         ...
        }
    ),
    ('pages.chapter.pie-chart', {
        'module': 'pages.chapter.pie-chart', 
        'path': '/chapter/pie-chart',
         ...
        }
    ),
    ...
])

In this example app, we will create a sidebar nav for the app pages located in the chapter/ folder. We use a dbc.Offcanvas() component and open the sidebar nav with a button.

Here is the app.py

import dash
from dash import dcc, html, Output, Input, State
import dash_labs as dl
import dash_bootstrap_components as dbc


app = dash.Dash(
    __name__,
    plugins=[dl.plugins.pages],
    external_stylesheets=[dbc.themes.BOOTSTRAP, dbc.icons.FONT_AWESOME],
)


navbar = dbc.NavbarSimple(
    dbc.DropdownMenu(
        [
            dbc.DropdownMenuItem(page["name"], href=page["path"])
            for page in dash.page_registry.values()
            if not page["path"].startswith("/chapter")
        ],
        nav=True,
        label="More Pages",
    ),
    brand="Multi Page App Plugin Demo",
    color="primary",
    dark=True,
    className="mb-2",
)

sidebar_button = dbc.Button(html.I(className="fa fa-bars"), id="sidebar-btn")
sidebar = dbc.Offcanvas(
    dbc.Nav(
        [html.H3("Chapters")]
        + [
            dbc.NavLink(
                [
                    html.I(className=page["icon"]),
                    html.Span(page["name"], className="ms-2"),
                ],
                href=page["path"],
                active="exact",
            )
            for page in dash.page_registry.values()
            if page["path"].startswith("/chapter")
        ],
        vertical=True,
        pills=True,
    ),
    id="offcanvas",
)

app.layout = dbc.Container(
    [
        navbar,
        dbc.Row(
            [
                dbc.Col([sidebar_button], width=1),
                dbc.Col([sidebar, dl.plugins.page_container]),
            ]
        ),
    ],
    fluid=True,
)


@app.callback(
    Output("offcanvas", "is_open"),
    Input("sidebar-btn", "n_clicks"),
    State("offcanvas", "is_open"),
)
def toggle_theme_offcanvas(n1, is_open):
    if n1:
        return not is_open
    return is_open


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

Recall from the previous chapter that dl.plugins.register_page also accepts arbitrary keyword arguments. We use this feature to store the icon used in the nav for each page.

Here is how we store the FontAwesome icon for pages/chapter/pie-chart.py

dl.plugins.register_page(__name__, icon="fas fa-chart-pie")

You can see how the icon is included in the sidebar navigation:

nested_folders