Dash does not work properly with DispatcherMiddleware

Consider the following:

import flask
import dash
import dash_html_components as html
from werkzeug.wsgi import DispatcherMiddleware

app = flask.Flask(__name__)

flask_app = flask.Flask(__name__)
@flask_app.route('/')
def index():
    return 'Flask App'

dash_app = dash.Dash(__name__)
dash_app.layout=html.Div('Dash App')


app.wsgi_app = DispatcherMiddleware(
    flask_app,
    {'/dash': dash_app.server},
)

if __name__ == '__main__':
    app.run(debug=True, port=8050, host='0.0.0.0')

I would expect to see “Flask App” on localhost:8050/ and “Dash App” on localhost:8050/dash/.

Instead, the Dash app doesn’t serve the _dash-* files from the right place:

127.0.0.1 - - [08/Aug/2018 10:43:52] "GET /dash/ HTTP/1.1" 200 -
127.0.0.1 - - [08/Aug/2018 10:43:52] "GET /_dash-layout HTTP/1.1" 404 -
127.0.0.1 - - [08/Aug/2018 10:43:52] "GET /_dash-dependencies HTTP/1.1" 404 -

[boarnoah]

Did you try configuring the dash_app’s ‘config.requests_pathname_prefix’ to use the prefix “dash”. I recall having to configure it so (was reverse proxying dash from nginx).

EDIT: Just tested your code, in this case set requests_pathname_prefix to a blank string. So: dash_app.config.requests_pathname_prefix = “”

Was able to get it to route properly.

[pjaol]

I realize this is closed but I’ve been banging my head against a wall trying to figure this out

DO NOT HAVE A TRAILING SLASH in your DispatchMiddleware mount points e.g.

# include trailing slash
dash_app = dash.Dash(__name__, requests_pathname_prefix="/dash/")

app.wsgi_app = DispatcherMiddleware(
    flask_app,
    # do not include trailing slash
    {'/dash': dash_app.server},
)

Failing to do so will result in 308 redirects