Following are example scripts to deploy Dash application in a sub-domain on an Apache web server installed with Flask and Dash modules. Hopefully this will be useful to someone who also experienced annoying issues of Dash stuck at a white window with “
Loading…” or “
dash error loading layout”.
Assume we will deploy the application in https://www.example.com/user1/myapp. First setup wsgi script, say "
index.wsgi", in the application folder with the following content:
import sys
# add your app directory to the sys.path
project_home = u'/home/users/user1/www/myapp' #specify to the correct path
if project_home not in sys.path:
sys.path = [project_home] + sys.path
# need to pass the flask app as "application" for WSGI to work
# for a dash app, that is at app.server
# see https://plot.ly/dash/deployment
from dashing_demo_app import app
application = app.server
app.config.update({
# as the proxy server will remove the prefix
#'routes_pathname_prefix': '',
# the front-end will prefix this string to the requests
# that are made to the proxy server
'requests_pathname_prefix': '/user1/myapp/index.wsgi/'
})
Please note that you need to specify requests_pathname_prefix to your url path, as it is the key to resolve the above issues of loading Dash app.
An example app script "dashing_demo_app.py" can be found from the reference link at the end (also copied below)
import dash
import dash_core_components as dcc
import dash_html_components as html
# for deployment, pass app.server (which is the actual flask app) to WSGI etc
app = dash.Dash()
app.layout = html.Div(children=[
html.H1(children='Hello Dash'),
html.Div(children='''
Dash: A web application framework for Python.
'''),
dcc.Graph(
id='example-graph',
figure={
'data': [
{'x': [1, 2, 3], 'y': [4, 1, 2], 'type': 'bar', 'name': 'SF'},
{'x': [1, 2, 3], 'y': [2, 4, 5], 'type': 'bar', 'name': u'Montréal'},
],
'layout': {
'title': 'Dash Data Visualization'
}
}
)
])
The original wsgi script and demo script are from https://github.com/conradho/dashingdemo/
