dash-auth-async 1.3.4

Dash Authorization and Login

Maintained by joschrag. Forked from plotly/dash-auth with the goal to add support for the new 4.x dash backends.

License: MIT

Feature overview

How this fork compares to upstream dash-auth. The headline difference is async: upstream is Flask-only, while dash-auth-async adds async callback support, the Quart and FastAPI backends, authenticated WebSocket callbacks, and a pluggable backend abstraction.

✅ supported · ❌ not supported

¹ detect_backend resolves Flask/Quart/FastAPI automatically; any other server is supported by supplying your own Backend instance.

² Supported on every backend, Flask included — you don't need Quart or FastAPI, just the async extra (bundled as dash-auth-async[async], which pulls in dash[async]).

³ Provided by the Quart and FastAPI backends only. WebSocket auth is a no-op on Flask, which has no WebSocket callback transport.

For local testing, install uv, then install the dev dependencies and run individual tests:

uv sync
uv run pytest -k ba001

Note that Python 3.10 or greater is required.

Usage

Basic Authentication

To add basic authentication, add the following to your Dash app:

from dash import Dash
from dash_auth_async import BasicAuth

app = Dash(__name__)
USER_PWD = {
    "username": "password",
    "user2": "useSomethingMoreSecurePlease",
}
BasicAuth(app, USER_PWD)

One can also use an authorization python function instead of a dictionary/list of usernames and passwords:

from dash import Dash
from dash_auth_async import BasicAuth

def authorization_function(username, password):
    if (username == "hello") and (password == "world"):
        return True
    else:
        return False


app = Dash(__name__)
BasicAuth(app, auth_func = authorization_function)

Public routes

You can whitelist routes from authentication with the add_public_routes utility function, or by passing a public_routes argument to the Auth constructor. The public routes should follow Flask's route syntax.

from dash import Dash
from dash_auth_async import BasicAuth, add_public_routes

app = Dash(__name__)
USER_PWD = {
    "username": "password",
    "user2": "useSomethingMoreSecurePlease",
}
BasicAuth(app, USER_PWD, public_routes=["/"])

add_public_routes(app, public_routes=["/user/<user_id>/public"])

NOTE: If you are using server-side callbacks on your public routes, you should also use dash_auth_async's new public_callback rather than the default Dash callback. Below is an example of a public route and callbacks on a multi-page Dash app using Dash's pages API:

app.py

from dash import Dash, html, dcc, page_container
from dash_auth_async import BasicAuth

app = Dash(__name__, use_pages=True, suppress_callback_exceptions=True)
USER_PWD = {
    "username": "password",
    "user2": "useSomethingMoreSecurePlease",
}
BasicAuth(app, USER_PWD, public_routes=["/", "/user/<user_id>/public"])

app.layout = html.Div(
    [
        html.Div(
            [
                dcc.Link("Home", href="/"),
                dcc.Link("John Doe", href="/user/john_doe/public"),
            ],
            style={"display": "flex", "gap": "1rem", "background": "lightgray", "padding": "0.5rem 1rem"},
        ),
        page_container,
    ],
    style={"display": "flex", "flexDirection": "column"},
)

if __name__ == "__main__":
    app.run(debug=True)

pages/home.py

from dash import Input, Output, html, register_page
from dash_auth_async import public_callback

register_page(__name__, "/")

layout = [
    html.H1("Home Page"),
    html.Button("Click me", id="home-button"),
    html.Div(id="home-contents"),
]

# Note the use of public callback here rather than the default Dash callback
@public_callback(
    Output("home-contents", "children"),
    Input("home-button", "n_clicks"),
)
def home(n_clicks):
    if not n_clicks:
        return "You haven't clicked the button."
    return "You clicked the button {} times".format(n_clicks)

pages/public_user.py

from dash import html, dcc, register_page

register_page(__name__, path_template="/user/<user_id>/public")

def layout(user_id: str):
    return [
        html.H1(f"User {user_id} (public)"),
        dcc.Link("Authenticated user content", href=f"/user/{user_id}/private"),
    ]

pages/private_user.py

from dash import html, register_page

register_page(__name__, path_template="/user/<user_id>/private")

def layout(user_id: str):
    return [
        html.H1(f"User {user_id} (authenticated only)"),
        html.Div("Members-only information"),
    ]

OIDC Authentication

To add authentication with OpenID Connect, you will first need to set up an OpenID Connect provider (IDP). This typically requires creating

• An application in your IDP
• Defining the redirect URI for your application, for testing locally you can use http://localhost:8050/oidc/callback
• A client ID and secret for the application

Once you have set up your IDP, you can add it to your Dash app as follows:

from dash import Dash
from dash_auth_async import OIDCAuth

app = Dash(__name__)

auth = OIDCAuth(app, secret_key="aStaticSecretKey!")
auth.register_provider(
    "idp",
    token_endpoint_auth_method="client_secret_post",
    # Replace the below values with your own
    # NOTE: Do not hardcode your client secret!
    client_id="<my-client-id>",
    client_secret="<my-client-secret>",
    server_metadata_url="<my-idp-.well-known-configuration>",
)

Once this is done, connecting to your app will automatically redirect to the IDP login page.

Running behind a reverse proxy

Behavior change. Earlier versions rewrote the OIDC callback host from the client-supplied X-Forwarded-Host header. That header trust was removed — an attacker could set it to steer the redirect_uri handed to your IDP (auth-code leak / open redirect). The redirect_uri is now built only from the host and scheme of the incoming request.

The consequence: behind a proxy that terminates TLS or rewrites the host, the redirect_uri comes out as http://localhost:8050/... and your IDP rejects it. To get the real public host and scheme back, restore it at the transport layer — where the trust can be bounded to your actual proxy, instead of trusting any client.

Two separate things to restore: scheme (http→https) and host. Most app servers forward the scheme but not the host — --forwarded-allow-ips / --proxy-headers only governs X-Forwarded-Proto/-For, never the host. So:

• Scheme: set force_https_callback=True on OIDCAuth (or pass the name of an env var that, when present, enables it). This covers the http→https half on every backend.
• Host: add proxy middleware that honours X-Forwarded-Host, sized to your real proxy-chain length:

Flask (WSGI — gunicorn, waitress, …):

from werkzeug.middleware.proxy_fix import ProxyFix

# Counts MUST equal your real proxy-chain length — setting them higher than the
# actual chain (or enabling this with no proxy) re-opens the spoofing hole.
app.server.wsgi_app = ProxyFix(app.server.wsgi_app, x_for=1, x_proto=1, x_host=1)

Quart (served by hypercorn) — wrap the ASGI app:

from hypercorn.middleware import ProxyFixMiddleware

# trusted_hops MUST equal your real proxy-chain length (see warning below).
app.server.asgi_app = ProxyFixMiddleware(app.server.asgi_app, mode="modern", trusted_hops=1)

FastAPI / Quart on uvicorn: uvicorn restores the scheme (--proxy-headers --forwarded-allow-ips=...) but not the host. Either have your proxy overwrite the Host header with the public host, or add a small trusted ASGI middleware that copies X-Forwarded-Host onto the host header — same trusted_hops discipline as above.

⚠️ Only restore proxy-header trust when a real proxy sets those headers, and set the hop counts to the actual chain length. A trusted-host middleware in front of no proxy lets a client spoof the host again — which is exactly the trust that was removed.

Multiple OIDC Providers

For multiple OIDC providers, you can use register_provider to add new ones after the OIDCAuth has been instantiated.

from dash import Dash, html
from dash_auth_async import OIDCAuth
from flask import request, redirect, url_for

app = Dash(__name__)

app.layout = html.Div([
    html.Div("Hello world!"),
    html.A("Logout", href="/oidc/logout"),
])

auth = OIDCAuth(
    app,
    secret_key="aStaticSecretKey!",
    # Set the route at which the user will select the IDP they wish to login with
    idp_selection_route="/login",
)
auth.register_provider(
    "IDP 1",
    token_endpoint_auth_method="client_secret_post",
    client_id="<my-client-id>",
    client_secret="<my-client-secret>",
    server_metadata_url="<my-idp-.well-known-configuration>",
)
auth.register_provider(
    "IDP 2",
    token_endpoint_auth_method="client_secret_post",
    client_id="<my-client-id2>",
    client_secret="<my-client-secret2>",
    server_metadata_url="<my-idp2-.well-known-configuration>",
)

@app.server.route("/login", methods=["GET", "POST"])
def login_handler():
    if request.method == "POST":
        idp = request.form.get("idp")
    else:
        idp = request.args.get("idp")

    if idp is not None:
        return redirect(url_for("oidc_login", idp=idp))

    return """<div>
        <form>
            <div>How do you wish to sign in:</div>
            <select name="idp">
                <option value="IDP 1">IDP 1</option>
                <option value="IDP 2">IDP 2</option>
            </select>
            <input type="submit" value="Login">
        </form>
    </div>"""


if __name__ == "__main__":
    app.run(debug=True)

Async backends

Known Limitations

⚠️ WebSocket callbacks & auth: Do not enable websocket_callbacks=True globally on an authenticated use_pages app. The global flag routes every callback — including Dash's built-in page-routing callback — over the WebSocket, which bypasses the HTTP before_request auth guard where the login challenge is issued. Navigating to a protected page then hangs (the socket closes with 4401 and reconnect-loops) instead of prompting for login — the prompt appears only after a full page reload. Opt individual streaming callbacks into websocket=True instead, so routing and login stay on HTTP.

Quart (async) Backend

dash-auth-async supports Dash's Quart backend for fully async request handling. Install the quart extra to pull in the required dependencies:

pip install dash-auth-async[quart]

Then pass backend="quart" when creating your Dash app. The auth setup is identical to the Flask examples above — no code changes required beyond the backend flag.

BasicAuth with Quart

from dash import Dash
from dash_auth_async import BasicAuth

app = Dash(__name__, backend="quart")

BasicAuth(app, {"admin": "admin", "viewer": "viewer123"})

if __name__ == "__main__":
    app.run(host="127.0.0.1", port=8050, debug=True)

OIDCAuth with Quart

import os
from dash import Dash, html
from dash_auth_async import OIDCAuth

app = Dash(__name__, backend="quart")

app.layout = html.Div([
    html.H2("OIDCAuth + Quart"),
    html.A("Logout", href="/oidc/logout"),
])

auth = OIDCAuth(app, secret_key="aStaticSecretKey!")
auth.register_provider(
    "myidp",
    client_id=os.environ["OIDC_CLIENT_ID"],
    client_secret=os.environ["OIDC_CLIENT_SECRET"],
    server_metadata_url=os.environ["OIDC_METADATA_URL"],
    token_endpoint_auth_method="client_secret_post",
    client_kwargs={"scope": "openid email profile"},
)

if __name__ == "__main__":
    app.run(host="127.0.0.1", port=8050, debug=True)

Note: The Quart backend requires Dash >= 4.2.0 and Python >= 3.10.

FastAPI (async) Backend

dash-auth-async supports Dash's FastAPI backend too. Install the fastapi extra to pull in the required dependencies:

pip install dash-auth-async[fastapi]

Then pass backend="fastapi" when creating your Dash app. BasicAuth and OIDCAuth work exactly as on Flask/Quart — no code changes beyond the backend flag.

BasicAuth with FastAPI

from dash import Dash
from dash_auth_async import BasicAuth

app = Dash(__name__, backend="fastapi")

BasicAuth(
    app,
    {"admin": "admin", "viewer": "viewer123"},
    secret_key="aStaticSecretKey!",  # enables sessions (SessionMiddleware)
)

if __name__ == "__main__":
    app.run(host="127.0.0.1", port=8050, debug=True)

OIDCAuth with FastAPI

import os
from dash import Dash, html
from dash_auth_async import OIDCAuth

app = Dash(__name__, backend="fastapi")

app.layout = html.Div([
    html.H2("OIDCAuth + FastAPI"),
    html.A("Logout", href="/oidc/logout"),
])

auth = OIDCAuth(app, secret_key="aStaticSecretKey!")
auth.register_provider(
    "myidp",
    client_id=os.environ["OIDC_CLIENT_ID"],
    client_secret=os.environ["OIDC_CLIENT_SECRET"],
    server_metadata_url=os.environ["OIDC_METADATA_URL"],
    token_endpoint_auth_method="client_secret_post",
    client_kwargs={"scope": "openid email profile"},
)

if __name__ == "__main__":
    app.run(host="127.0.0.1", port=8050, debug=True)

Notes:

• A secret_key installs Starlette's SessionMiddleware automatically. If you add your own SessionMiddleware, dash-auth-async defers to it.
• Auth/OIDCAuth must be constructed before the server starts serving (Starlette forbids adding middleware after startup) — the normal usage pattern.
• OIDC uses authlib's official starlette_client; no extra client module required.

The FastAPI backend requires Dash >= 4.2.0 and Python >= 3.10.

User-group-based permissions

dash_auth_async provides a convenient way to secure parts of your app based on user groups.

The following utilities are defined:

• list_groups: Returns the groups of the current user, or None if the user is not authenticated.
• check_groups: Checks the current user groups against the provided list of groups. Available group checks are one_of, all_of and none_of. The function returns None if the user is not authenticated.
• protected: A function decorator that modifies the output if the user is unauthenticated or missing group permission.
• protected_callback: A callback that only runs if the user is authenticated and with the right group permissions.

NOTE: user info is stored in the session so make sure you define a secret_key on the server to use this feature.

If you wish to use this feature with BasicAuth, you will need to define the groups for individual basicauth users:

from dash_auth_async import BasicAuth

app = Dash(__name__)
USER_PWD = {
    "username": "password",
    "user2": "useSomethingMoreSecurePlease",
}
BasicAuth(
    app,
    USER_PWD,
    user_groups={"username": ["group1", "group2"], "user2": ["group2"]},
    secret_key="Test!",
)

# You can also use a function to get user groups
def check_user(username, password):
    if username == "user1" and password == "password":
        return True
    if username == "user2" and password == "useSomethingMoreSecurePlease":
        return True
    return False

def get_user_groups(user):
    if user == "user1":
        return ["group1", "group2"]
    elif user == "user2":
        return ["group2"]
    return []

BasicAuth(
    app,
    auth_func=check_user,
    user_groups=get_user_groups,
    secret_key="Test!",
)