from flask import Flask, redirect, request, session
import datetime
import dash
import json
from dash import dcc, html, Input, Output
# Initialize Flask and Dash apps
server = Flask(__name__)
server.secret_key = 'your_secret_key' # Used to protect the session
server.config['PERMANENT_SESSION_LIFETIME'] = datetime.timedelta(seconds=30)
app = dash.Dash(__name__, server=server, url_base_pathname='/')
# Let's assume this is the function to check the user's logged-in status
def user_is_logged_in():
return bool(session.get('user'))
@server.route('/login', methods=['GET', 'POST'])
def login_page():
session.permanent = True
if request.method == "POST":
session['user'] = f"{request.form['username']}:{request.form['password']}"
return redirect('/')
else:
return ('<form method="post">'
'<input type="text" name="username" id="un" title="username" placeholder="username"/>'
'<input type="password" name="password" id="pw" title="username" placeholder="password"/>'
'<button type="submit">Login</button>'
'</form>')
@server.before_request
def before_request_func():
# Check if the user is logged in
if not user_is_logged_in() and request.path != '/login':
# Check the request path and method
if request.path == '/_dash-update-component' and request.method == 'POST':
# If the user is not logged in, return a JSON response to redirect to /login
return json.dumps({
"multi": True,
"response": {
"page-content": {
"children": {
"props": {'id': 'url', 'href': '/login'},
"type": "Location",
"namespace": "dash_core_components"
}
}
}
})
else:
return redirect('/login')
d = {v: v.capitalize() for v in ['a', 'b', 'c', 'd']}
app.layout = html.Div([
dcc.Location(id='url', refresh=True),
html.Div(
[
html.Label('Labels'),
dcc.Dropdown([{'label': v, 'value': k} for k, v in d.items()],
value=None, id='dropdown'),
html.Div('Select one of the label'),
],
),
html.Div(id="indicator"),
])
@app.callback(
Output('indicator', 'children'),
[Input('dropdown', 'value')],
prevent_initial_call=True)
def update_indicator(val):
return d[val]
# Run the server
if __name__ == '__main__':
server.run(port=5008)
I took a look at your example, but unfortunately, it doesn’t respond to my case. I leave minimal example of my case. As you can see, it has a session lifespan, and when session expires, and a user uses dropdown nothing happens, but in network you can see that backend returns the corresponding JSON to change location. Could you look at my case?
