Hide admin page for unauthorized users

[bralbral]

Checklist

• The bug is reproducible against the latest release or master.
• There are no similar issues or pull requests to fix it yet.

Describe the bug

According documentation we can use middleware for hiding admin page from some users.

If user is not is_authenticated it shows:

Steps to reproduce the bug

Just add auth middleware like this:

from sqladmin import Admin, ModelAdmin
from starlette.applications import Starlette
from starlette.requests import Request

# AuthenticationMiddleware explained in Starlette docs

middlewares = [
    Middleware(AuthenticationMiddleware, backend=BasicAuthBackend())
]

app = Starlette()
admin = Admin(app=app, engine=engine, middlewares=middlewares)


class AuthModelAdmin(ModelAdmin):
    def is_accessible(self, request: Request) -> bool:
        # With Authentication backend you can now access request.user.
        if request.user.is_authenticated:
            return True
        return False

Expected behavior

Do not show page; raise error

Actual behavior

No response

Debugging material

No response

Environment

SMP Debian 5.10.106-1 (2022-03-17)
Python 3.9

Additional context

No response

[aminalaee]

Hey, thanks for the suggestion. Yes that makes sense.
The problem is there might be some classes not inheriting from AuthModelAdmin so they might be visible in the page.
There should be a generic way to control this via middlewares maybe. Let me take a look.

[aminalaee]

I've added basic support for Authentication in #277

I'll update the documentation how to use it, but this will achieve what you want.