Authorization callbacks

The OAuth providers integrated with Panel provide an easy way to enable authentication on your applications. This verifies the identity of a user and also provides some level of access control (i.e. authorization). However often times the OAuth configuration is controlled by a corporate IT department or is otherwise difficult to manage so its often easier to grant permissions to use the OAuth provider freely but then restrict access controls in the application itself. To manage access you can provide an authorize_callback as part of your applications.

The authorize_callback can be configured on pn.config or via the pn.extension:

import panel as pn

def authorize(user_info):
    with open('users.txt') as f:
        valid_users = f.readlines()
    return user_info['username'] in valid_users

pn.config.authorize_callback = authorize # or pn.extension(..., authorize_callback=authorize)

The authorize_callback is given a dictionary containing the data in the OAuth provider’s id_token and optionally the current endpoint that the user is trying to access. The example above checks whether the current user is in the list of users specified in a user.txt file. However you can implement whatever logic you want to either grant a user access or reject it.

You may return either a boolean True/False value OR a string, which will be used to redirect the user to a different URL or endpoint. As an example, you may redirect users to specific endpoints:

def authorize(user_info, page):
    user = user_info['user']
    if page == "/":
        if user in ADMINS:
            return '/admin'
        else:
            return '/user'
    elif user in ADMINS:
        return True
    else:
        return page.startswith('/user')

The callback above would direct users visiting the root (/) to the appropriate endpoint depending on whether they are in the list of ADMINS. If the user is an admin they are granted access to both the /user and /admin endpoints while non-admin users will only be granted access to the /user endpoint.

If a user is not authorized, i.e. the callback returns False, they will be presented with an authorization error template which can be configured using the --auth-template commandline option or by setting config.auth_template.

The auth template must be a valid Jinja2 template and accepts a number of arguments:

• {{ title }}: The page title.

• {{ error_type }}: The type of error.

• {{ error }}: A short description of the error.

• {{ error_msg }}: A full description of the error.

The authorize_callback may also contain a second parameter, which is set by the requested application path. You can use this extra parameter to check if a user is authenticated and has access to the application at the given path.

from urllib import parse
import panel as pn

authorized_user_paths = {
    "user1": ["/app1", "/app2"],
    "user2": ["/app1"],
}

def authorize(user_info, request_path):
    if current_user := authorized_user_paths.get(user_info['username']):
        current_path = parse.urlparse(request_path).path
        current_user_paths = authorized_user_paths[current_user]
        return current_path in current_user_paths
    return False

pn.config.authorize_callback = authorize