feat: add LDAP functions (authenticate, sync, parse, upsert)

app/modules/auth/ldap.py

@@ -0,0 +1,181 @@
+import logging
+import time
+from datetime import datetime, timedelta, timezone
+from typing import Optional
+
+from ldap3 import ALL, ALL_ATTRIBUTES, NTLM, Connection, Server
+from ldap3.core.exceptions import LDAPSocketOpenError
+from sqlalchemy.orm import Session
+
+from app.modules.auth.models import User
+
+logger = logging.getLogger(__name__)
+
+
+def ldap_authenticate(
+    username: str,
+    password: str,
+    ldap_server: str,
+    ldap_domain: str,
+) -> Optional[dict]:
+    """NTLM bind + fetch user attributes. Returns attrs dict on success, None on failure."""
+    server = Server(ldap_server, get_info=ALL, connect_timeout=8)
+    conn = Connection(
+        server,
+        user=f"{ldap_domain}\\{username}",
+        password=password,
+        authentication=NTLM,
+    )
+    try:
+        conn.bind()
+    except LDAPSocketOpenError:
+        logger.warning("LDAP server %s not reachable", ldap_server)
+        return None
+    except Exception:
+        logger.warning("LDAP bind failed for user %s", username, exc_info=True)
+        return None
+
+    if not conn.extend.standard.who_am_i():
+        conn.unbind()
+        return None
+
+    conn.search(
+        search_base=f"DC={ldap_domain},DC=fh-nuernberg,DC=de",
+        search_filter=f"(&(objectclass=user)(CN={username}))",
+        attributes=ALL_ATTRIBUTES,
+    )
+
+    if not conn.entries:
+        conn.unbind()
+        logger.warning("LDAP: user %s authenticated but no entry found", username)
+        return None
+
+    attrs = _parse_entry(conn.entries[0])
+    conn.unbind()
+    return attrs
+
+
+def _parse_entry(entry) -> dict:
+    def val(field: str, default: str = "N.N.") -> str:
+        try:
+            v = entry[field].value
+            return str(v)[:64] if v else default
+        except Exception:
+            return default
+
+    def expire_date(field: str) -> Optional[datetime]:
+        try:
+            v = entry[field].value
+            if v is None:
+                return None
+            if isinstance(v, datetime):
+                dt = v
+            else:
+                dt = datetime(v.year, v.month, v.day, tzinfo=timezone.utc)
+            if dt.tzinfo is None:
+                dt = dt.replace(tzinfo=timezone.utc)
+            return None if dt.year >= 2099 else dt
+        except Exception:
+            return None
+
+    return {
+        "username": val("sAMAccountName"),
+        "full_name": (f"{val('givenName', '')} {val('sn', '')}".strip() or "N.N."),
+        "department": val("department"),
+        "role": val("description"),
+        "account_expires": expire_date("accountExpires"),
+    }
+
+
+def _has_to_update(db: Session, min_interval_hours: int) -> bool:
+    """True if a background sync is due."""
+    deadline = datetime.now(timezone.utc) - timedelta(hours=min_interval_hours)
+    latest = (
+        db.query(User)
+        .filter(User.pw_hash.is_(None))
+        .order_by(User.updated_at.desc())
+        .first()
+    )
+    if latest is None:
+        return True
+    last = latest.updated_at
+    if last.tzinfo is None:
+        last = last.replace(tzinfo=timezone.utc)
+    return last < deadline
+
+
+def _upsert_from_attrs(db: Session, attrs: dict) -> None:
+    """Create or update a User from AD attribute dict (no commit)."""
+    user = db.query(User).filter(User.username == attrs["username"]).first()
+    if user is None:
+        user = User(username=attrs["username"])
+        db.add(user)
+    user.full_name = attrs["full_name"]
+    user.department = attrs["department"]
+    user.role = attrs["role"]
+    user.account_expires = attrs["account_expires"]
+
+
+def sync_all_users(
+    username: str,
+    password: str,
+    ldap_server: str,
+    ldap_domain: str,
+    ldap_search_base: str,
+    min_interval_hours: int,
+    letter_delay_seconds: float,
+) -> None:
+    """Login-triggered background sync of all AD users. Creates its own DB session."""
+    from app.core.database import SessionLocal
+
+    with SessionLocal() as db:
+        if not _has_to_update(db, min_interval_hours):
+            logger.info("LDAP sync skipped: last sync is recent")
+            return
+
+        server = Server(ldap_server, get_info=ALL, connect_timeout=8)
+        conn = Connection(
+            server,
+            user=f"{ldap_domain}\\{username}",
+            password=password,
+            authentication=NTLM,
+        )
+        try:
+            conn.bind()
+        except Exception:
+            logger.warning("LDAP sync: bind failed", exc_info=True)
+            return
+
+        found_usernames: set[str] = set()
+        chars = "abcdefghijklmnopqrstuvwxyz_"
+
+        for char in chars:
+            try:
+                conn.search(
+                    search_base=ldap_search_base,
+                    search_filter=f"(&(objectclass=user)(CN={char}*))",
+                    attributes=ALL_ATTRIBUTES,
+                )
+                for entry in conn.entries:
+                    try:
+                        attrs = _parse_entry(entry)
+                        found_usernames.add(attrs["username"])
+                        _upsert_from_attrs(db, attrs)
+                    except Exception:
+                        logger.warning("LDAP sync: failed to parse entry", exc_info=True)
+                db.commit()
+            except Exception:
+                logger.warning("LDAP sync: search failed for prefix '%s'", char, exc_info=True)
+
+            if letter_delay_seconds > 0:
+                time.sleep(letter_delay_seconds)
+
+        # Deactivate LDAP users no longer in AD
+        ldap_users = db.query(User).filter(User.pw_hash.is_(None)).all()
+        for user_obj in ldap_users:
+            if user_obj.username not in found_usernames:
+                logger.info("LDAP sync: deactivating %s (not in AD)", user_obj.username)
+                user_obj.is_active = False
+        db.commit()
+        conn.unbind()
+        logger.info("LDAP sync complete — %d users found", len(found_usernames))