add json cursor

Author: jaredlewis

docs/release_notes.rst

@@ -1,6 +1,10 @@
 Release Notes
 =============
 
+v3.0.2
+------
+* Add `json_cursor` to handle django no longer automatically parsing json fields
+
 v3.0.1
 ------
 * Switch to github actions

querybuilder/cursor.py

@@ -0,0 +1,16 @@
+import contextlib
+import json
+import psycopg2
+
+
+@contextlib.contextmanager
+def json_cursor(django_database_connection):
+    """
+    Cast json fields into their specific types to account for django bugs
+    https://code.djangoproject.com/ticket/31956
+    https://code.djangoproject.com/ticket/31973
+    https://www.psycopg.org/docs/extras.html#psycopg2.extras.register_default_jsonb
+    """
+    with django_database_connection.cursor() as cursor:
+        psycopg2.extras.register_default_jsonb(conn_or_curs=cursor.cursor, loads=json.loads)
+        yield cursor

querybuilder/tests/cursor_tests.py

@@ -0,0 +1,15 @@
+from django.db import connection
+
+from querybuilder.cursor import json_cursor
+from querybuilder.tests.base import QuerybuilderTestCase
+from querybuilder.tests.models import MetricRecord
+
+
+class JsonCursorTests(QuerybuilderTestCase):
+    def test_json_cursor(self):
+        data = {'one': 1, 'two': 2}
+        MetricRecord.objects.create(data=data)
+        with json_cursor(connection) as cursor:
+            cursor.execute(f'select data from {MetricRecord._meta.db_table}')
+            record = cursor.fetchone()
+            self.assertEqual(record[0], data)

querybuilder/version.py

@@ -1 +1 @@
-__version__ = '3.0.1'
+__version__ = '3.0.2'