fix: 修复只配置DC域时，LDAP用户认证失败的问题

apps/authentication/backends/ldap.py

@@ -82,6 +82,12 @@ class LDAPAuthorizationBackend(LDAPBackend):
 
 class LDAPUser(_LDAPUser):
 
+    def _search_for_user_dn_from_ldap_util(self):
+        from settings.utils import LDAPServerUtil
+        util = LDAPServerUtil()
+        user_dn = util.search_for_user_dn(self._username)
+        return user_dn
+
     def _search_for_user_dn(self):
         """
         This method was overridden because the AUTH_LDAP_USER_SEARCH
@@ -107,7 +113,10 @@ class LDAPUser(_LDAPUser):
         if results is not None and len(results) == 1:
             (user_dn, self._user_attrs) = next(iter(results))
         else:
-            user_dn = None
+            # 解决直接配置DC域，用户认证失败的问题(库不能从整棵树中搜索)
+            user_dn = self._search_for_user_dn_from_ldap_util()
+            self._user_dn = user_dn
+            self._user_attrs = self._load_user_attrs()
 
         return user_dn