Add support for lists as dict values

stix2/datastore/relational_db/query.py

@@ -1,3 +1,4 @@
+import collections
 import inspect
 
 import sqlalchemy as sa
@@ -280,7 +281,15 @@ def _read_kill_chain_phases(stix_id, type_table, metadata, conn):
     return kill_chain_phases
 
 
-def _read_dictionary_property(stix_id, type_table, prop_name, prop_instance, metadata, conn):
+def _read_dictionary_property(
+    stix_id,
+    type_table,
+    prop_name,
+    prop_instance,
+    metadata,
+    conn,
+    db_backend
+):
     """
     Read a dictionary from a table.
 
@@ -292,23 +301,57 @@ def _read_dictionary_property(stix_id, type_table, prop_name, prop_instance, met
     :param metadata: SQLAlchemy Metadata object containing all the table
         information
     :param conn: An SQLAlchemy DB connection
+    :param db_backend: A backend object with information about how data is
+        stored in the database
     :return: The dictionary, or None if no dictionary entries were found
     """
     dict_table_name = f"{type_table.fullname}_{prop_name}"
     dict_table = metadata.tables[dict_table_name]
 
     if len(prop_instance.valid_types) == 1:
-        stmt = sa.select(
-            dict_table.c.name, dict_table.c.value,
-        ).where(
-            dict_table.c.id == stix_id,
-        )
+        valid_type = prop_instance.valid_types[0]
+
+        if isinstance(valid_type, stix2.properties.ListProperty):
+            if db_backend.array_allowed():
+                stmt = sa.select(
+                    dict_table.c.name, dict_table.c["values"],
+                ).where(
+                    dict_table.c.id == stix_id,
+                )
 
-        results = conn.execute(stmt)
-        dict_value = dict(results.all())
+                results = conn.execute(stmt)
+                dict_value = dict(results.all())
+
+            else:
+                # Dict contains a list, but array columns are not supported.
+                # So query from an auxiliary table.
+                list_table_name = f"{dict_table_name}_values"
+                list_table = metadata.tables[list_table_name]
+                stmt = sa.select(
+                    dict_table.c.name, list_table.c.value
+                ).select_from(dict_table).join(
+                    list_table, list_table.c.id == dict_table.c.values
+                ).where(
+                    dict_table.c.id == stix_id
+                )
+
+                results = conn.execute(stmt)
+                dict_value = collections.defaultdict(list)
+                for key, value in results:
+                    dict_value[key].append(value)
+
+        else:
+            stmt = sa.select(
+                dict_table.c.name, dict_table.c.value,
+            ).where(
+                dict_table.c.id == stix_id,
+            )
+
+            results = conn.execute(stmt)
+            dict_value = dict(results.all())
 
     else:
-        # In this case, we get one column per valid type
+        # In this case, we get one column per valid type (assume no lists here)
         type_cols = (col for col in dict_table.c if col.key not in ("id", "name"))
         stmt = sa.select(dict_table.c.name, *type_cols).where(dict_table.c.id == stix_id)
         results = conn.execute(stmt)
@@ -437,7 +480,15 @@ def _read_embedded_object_list(fk_id, join_table, embedded_type, metadata, conn)
     return obj_list
 
 
-def _read_complex_property_value(obj_id, prop_name, prop_instance, obj_table, metadata, conn):
+def _read_complex_property_value(
+    obj_id,
+    prop_name,
+    prop_instance,
+    obj_table,
+    metadata,
+    conn,
+    db_backend
+):
     """
     Read property values which require auxiliary tables to store.  These are
     idiosyncratic and just require a lot of special cases.  This function has
@@ -456,6 +507,8 @@ def _read_complex_property_value(obj_id, prop_name, prop_instance, obj_table, me
     :param metadata: SQLAlchemy Metadata object containing all the table
         information
     :param conn: An SQLAlchemy DB connection
+    :param db_backend: A backend object with information about how data is
+        stored in the database
     :return: The property value
     """
 
@@ -523,7 +576,15 @@ def _read_complex_property_value(obj_id, prop_name, prop_instance, obj_table, me
     elif isinstance(prop_instance, stix2.properties.DictionaryProperty):
         # ExtensionsProperty/HashesProperty subclasses DictionaryProperty, so
         # this must come after those
-        prop_value = _read_dictionary_property(obj_id, obj_table, prop_name, prop_instance, metadata, conn)
+        prop_value = _read_dictionary_property(
+            obj_id,
+            obj_table,
+            prop_name,
+            prop_instance,
+            metadata,
+            conn,
+            db_backend
+        )
 
     elif isinstance(prop_instance, stix2.properties.EmbeddedObjectProperty):
         prop_value = _read_embedded_object(
@@ -611,6 +672,7 @@ def _read_complex_top_level_property_value(
             type_table,
             metadata,
             conn,
+            db_backend
         )
 
     return prop_value