ldapgate 0.1.5

Lightweight LDAP/AD authentication proxy and FastAPI middleware

LDAPGate

Lightweight LDAP/AD authentication gateway for Python web apps. Install it, configure it, done.

Features

• Two deployment modes — standalone reverse proxy or drop-in FastAPI middleware
• WebDAV + browser in one — browsers get a login form; WebDAV clients (Windows, macOS Finder, curl) get a Basic auth challenge — same endpoint, no extra config
• Pure Python LDAP — no OS-level libs required, uses ldap3
• Signed cookie sessions — stateless, no server-side session storage
• OpenLDAP and Active Directory — uid= and sAMAccountName= out of the box
• Optional group gating — restrict access to members of a specific LDAP group
• Header injection — injects X-Forwarded-User for downstream apps
• Bundled login form — responsive, dark/light mode, customisable, works air-gapped

Install

pip install ldapgate

Config file

Both modes share the same ldapgate.yaml:

ldap:
  url: ldaps://dc.example.com:636
  bind_dn: CN=svc,CN=Users,DC=example,DC=com
  bind_password: secret
  base_dn: DC=example,DC=com
  user_filter: "(sAMAccountName={username})"         # AD; OpenLDAP: (uid={username})
  # LDAPGate requires at least one authorization rule by default:
  group_dn: CN=app-users,CN=Users,DC=example,DC=com  # restrict by group
  allowed_users:                                      # or restrict by local allowlist
    - alice
    - bob
  timeout: 10
  tls_validate: REQUIRED                             # NONE | OPTIONAL | REQUIRED
  tls_ca_cert_file: /etc/ssl/certs/internal-ca.pem  # optional — custom CA bundle
  tls_client_cert_file: /etc/ssl/certs/client.pem   # optional — mutual TLS client cert
  tls_client_key_file: /etc/ssl/private/client.key  # optional — mutual TLS client key

proxy:
  listen_host: 0.0.0.0
  listen_port: 9000
  backend_url: http://localhost:8080
  secret_key: change-me-to-something-random
  session_ttl: 3600
  user_header: X-Forwarded-User
  login_path: /_auth/login
  logout_path: /_auth/logout
  app_name: MyApp
  secure_cookies: false                              # set true when behind HTTPS

All settings can also be provided via environment variables using __ as a separator — e.g. LDAP__URL, PROXY__SECRET_KEY.

Corporate / Active Directory setup

For corp environments with internal CAs where cert validation isn't feasible:

ldap:
  url: ldaps://dc.example.com:636
  tls_validate: NONE
  # ... other settings ...

⚠️ Warning: tls_validate: NONE disables all TLS certificate validation and makes you vulnerable to man-in-the-middle attacks. Whenever possible, use tls_ca_cert_file to trust your internal CA instead.

For plain LDAP with STARTTLS:

ldap:
  url: ldap://dc.example.com:389
  use_starttls: true

---

Mode 1 — Standalone Reverse Proxy

Run ldapgate as a standalone process in front of any app.

Browser / WebDAV client → ldapgate :9000 → backend app :8080

ldapgate serve --config ldapgate.yaml

All traffic is intercepted by ldapgate before reaching the backend. Authenticated requests are forwarded with the X-Forwarded-User header set to the verified username. Apps can point their logout link at the configured logout_path (default /_auth/logout) to clear the session.

WebDAV clients receive a 401 WWW-Authenticate: Basic challenge automatically and authenticate per-request via HTTP Basic auth — no session cookie needed.

---

Mode 2 — FastAPI Middleware

Drop ldapgate auth directly into an existing FastAPI app — no separate process.

from fastapi import FastAPI
from ldapgate.config import load_config
from ldapgate.middleware import add_ldap_auth

app = FastAPI()
config = load_config("ldapgate.yaml")
add_ldap_auth(app, config)

@app.get("/api/data")
async def data(request):
    return {"user": request.state.user}  # authenticated username

add_ldap_auth registers the login/logout routes and attaches the middleware in one call. The authenticated username is available as request.state.user and is also injected as the configured user_header into the request headers.

WebDAV with middleware

The middleware handles both browser and WebDAV clients on the same app instance:

Client	Auth flow
Browser	Redirected to login form → session cookie
WebDAV (Windows, macOS Finder, curl)	401 WWW-Authenticate: Basic challenge → Basic auth per-request

No extra routes or config needed — if a request arrives without a session cookie and without Accept: text/html, the middleware issues a 401 with a WWW-Authenticate: Basic header. The client sends credentials, the middleware validates against LDAP, and the request proceeds.

allowed_users and group_dn apply to both flows — a user blocked by those settings is rejected regardless of whether they authenticated via cookie or Basic auth.

Example — xwing file server with WebDAV:

from fastapi import FastAPI
from ldapgate.config import load_config
from ldapgate.middleware import add_ldap_auth
from xwing.app import create_app
from xwing.config import Settings

xwing_settings = Settings(root_dir="/srv/files", users_config="users.yaml")
app = create_app(xwing_settings)

ldap_config = load_config("ldapgate.yaml")
add_ldap_auth(app, ldap_config)

Windows users can now map http://your-server:8989/ as a network drive:

net use Z: http://your-server:8989/ /user:alice /persistent:yes

macOS Finder: Go → Connect to Server (⌘K) → http://your-server:8989/

---

CLI reference

ldapgate serve [OPTIONS]

  --config PATH     Path to ldapgate.yaml (reads env vars if omitted)
  --host TEXT       Override listen host
  --port INTEGER    Override listen port
  --backend TEXT    Override backend URL
  --reload          Enable auto-reload (dev only)

---

Development

Requires uv.

git clone https://github.com/anudeepd/ldapgate
cd ldapgate
uv sync
uv run pytest

License

MIT