Add ldap.filter.is_filter() which checks filter syntax

spaceone · spaceone · commit ff33e7ec7e0a · 2020-11-13T23:17:13.000+01:00
diff --git a/Lib/ldap/filter.py b/Lib/ldap/filter.py
@@ -87,3 +87,21 @@ def time_span_filter(
         until_timestr=strf_secs(until_timestamp),
     )
     # end of time_span_filter()
+
+
+def is_filter(filter_):
+    """
+    Returns True if `filter_' can be parsed as a valid LDAP filter, otherwise False is returned.
+    """
+    import ldap
+    lo = ldap.initialize('')
+    try:
+        lo.search_ext_s('', ldap.SCOPE_BASE, filter_)
+    except (ldap.FILTER_ERROR, TypeError, ValueError):
+        return False
+    except ldap.SERVER_DOWN:
+        # the filter syntax is valid, as the connection is not bound we expecte SERVER_DOWN here
+        return True
+    finally:
+        lo.unbind()
+    raise RuntimeError('Could not check filter syntax.')  # can not happen
