see https://github.com/plotly/dash/issues/1056#issuecomment-997439760 or comment

dash_save_html.py

# -*- coding: utf-8 -*-
import os
from html.parser import HTMLParser

import dash
import pandas as pd
import plotly.express as px
import requests
from dash import html, dcc, dash_table, Input, Output


def patch_file(file_path: str, content: bytes, extra: dict = None) -> bytes:
    if file_path == 'index.html':
        index_html_content = content.decode('utf8')
        extra_jsons = f'''
        var patched_jsons_content={{
        {','.join(["'/" + k + "':" + v.decode("utf8") + "" for k, v in extra.items()])}
        }};
        '''
        patched_content = index_html_content.replace(
            '<footer>',
            f'''
            <footer>
            <script>
            ''' + extra_jsons + '''
            const origFetch = window.fetch;
            window.fetch = function () {
                const e = arguments[0]
                if (patched_jsons_content.hasOwnProperty(e)) {
                    return Promise.resolve({
                        json: () => Promise.resolve(patched_jsons_content[e]),
                        headers: new Headers({'content-type': 'application/json'}),
                        status: 200,
                    });
                } else {
                    return origFetch.apply(this, arguments)
                }
            }
            </script>
            '''
        ).replace(
            'href="/',
            'href="'
        ).replace(
            'src="/',
            'src="'
        )
        return patched_content.encode('utf8')
    else:
        return content


def write_file(file_path: str, content: bytes, target_dir='target', ):
    target_file_path = os.path.join(target_dir, file_path.lstrip('/').split('?')[0])
    target_leaf_dir = os.path.dirname(target_file_path)
    os.makedirs(target_leaf_dir, exist_ok=True)
    with open(target_file_path, 'wb') as f:
        f.write(content)
    pass


class ExternalResourceParser(HTMLParser):
    def __init__(self):
        super().__init__()
        self.resources = []

    def handle_starttag(self, tag, attrs):
        if tag == 'link':
            for k, v in attrs:
                if k == 'href':
                    self.resources.append(v)
        if tag == 'script':
            for k, v in attrs:
                if k == 'src':
                    self.resources.append(v)


def make_static(base_url, target_dir='target'):
    index_html_bytes = requests.get(base_url).content
    json_paths = ['_dash-layout', '_dash-dependencies', ]
    extra_json = {}
    for json_path in json_paths:
        json_content = requests.get(base_url + json_path).content
        extra_json[json_path] = json_content

    patched_bytes = patch_file('index.html', index_html_bytes, extra=extra_json)
    write_file('index.html', patched_bytes, target_dir)
    parser = ExternalResourceParser()
    parser.feed(patched_bytes.decode('utf8'))
    extra_js = [
        '_dash-component-suites/dash/dcc/async-graph.js',
        '_dash-component-suites/dash/dcc/async-plotlyjs.js',
        '_dash-component-suites/dash/dash_table/async-table.js',
        '_dash-component-suites/dash/dash_table/async-highlight.js'
    ]
    for resource_url in parser.resources + extra_js:
        resource_url_full = base_url + resource_url
        print(f'get {resource_url_full}')
        resource_bytes = requests.get(resource_url_full).content
        patched_bytes = patch_file(resource_url, resource_bytes)
        write_file(resource_url, patched_bytes, target_dir)


def main():
    port = 9050
    app = dash.Dash(__name__)
    df = pd.DataFrame({
        "Fruit": ["Apples", "Oranges", "Bananas", "Apples", "Oranges", "Bananas"],
        "Amount": [4, 1, 2, 2, 4, 5],
        "City": ["SF", "SF", "SF", "Montreal", "Montreal", "Montreal"]
    })

    fig = px.bar(df, x="Fruit", y="Amount", color="City", barmode="group")

    app.layout = html.Div(children=[
        html.Button('save static', id='save', n_clicks=0),
        html.Span('', id='saved'),

        html.H1(children='Hello Dash'),

        html.Div(children='''
            Dash: A web application framework for your data.
        '''),

        dcc.Graph(
            id='example-graph',
            figure=fig
        ),
        dash_table.DataTable(
            id='table',
            columns=[{"name": i, "id": i} for i in df.columns],
            data=df.to_dict('records'),
        )
    ])

    @app.callback(
        Output('saved', 'children'),
        Input('save', 'n_clicks'),
    )
    def save_result(n_clicks):
        if n_clicks == 0:
            return 'not saved'
        else:
            make_static(f'http://127.0.0.1:{port}/')
            return 'saved'

    app.run_server(debug=False, port=port)


if __name__ == '__main__':
    main()

Hey,
Great Post Man!!!
Is it possible to save to html directly (line135, After defining the layout)

Hi, exzhawk

I have run your code in vscode, and click the "save" button in the server, then create a 'target' folder normally. But there is no figure graph in the 'index.html', only the table and other divs in the page.

There is the console log in html page. and an error in vscode terminal. Could you help me with this issue? Thanks.

Hi. Very nice snippet!!!
For those encountering the issue mentioned by @RajonDawn, just change these:
extra_js = [
"_dash-component-suites/dash/dcc/async-graph.js",
# "_dash-component-suites/dash/dcc/async-plotlyjs.js", # TODO: remove
"_dash-component-suites/dash/dash_table/async-table.js",
"_dash-component-suites/dash/dash_table/async-highlight.js",
"_dash-component-suites/plotly/package_data/plotly.min.js", # TODO: add
]