This is related to this post but the solution does not work.
I have SSO auth passing in a request header with a username. In a Flask app I can get the username back using flask.request.headers['username']. In Dash I get a server error. Here is the Dash app - it is using gunicorn.
import dash
from dash import html
import plotly.graph_objects as go
from dash import dcc
from dash.dependencies import Input, Output
import flask
from flask import request
server = flask.Flask(__name__) # define flask app.server
app = dash.Dash(__name__, serve_locally=False, server=server)
username = request.headers['username']
greeting = "Hello " + username
app.layout = html.Div(children=[
html.H1(children=greeting),
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'
}
}
)
])
if __name__ == '__main__':
app.run_server()
Any help would be much appreciated.
You can only access the request object from within a request context. In Dash terminology that means from within a callback. Here is a small example,
from dash import html, Input, Output, Dash
from flask import request
app = Dash(__name__)
app.layout = html.Div(children=[
html.Div(id="greeting"),
html.Div(id="dummy") # dummy element to trigger callback on page load
])
@app.callback(Output("greeting", "children"), Input("dummy", "children"))
def say_hello(_):
host = request.headers['host'] # host should always be there
return f"Hello from {host}!"
if __name__ == '__main__':
app.run_server()