Fix: Encode strings as JSON in JSONQueryString where clauses (fixes #1118)

piccolo/query/operators/json.py

@@ -3,7 +3,7 @@
 from typing import TYPE_CHECKING, Any, Optional, Union
 
 from piccolo.querystring import QueryString
-from piccolo.utils.encoding import dump_json
+from piccolo.utils.encoding import dump_json, load_json
 
 if TYPE_CHECKING:
     from piccolo.columns.column_types import JSON
@@ -12,9 +12,17 @@
 class JSONQueryString(QueryString):
 
     def clean_value(self, value: Any):
-        if not isinstance(value, (str, QueryString)):
-            value = dump_json(value)
-        return value
+        if isinstance(value, QueryString):
+            return value
+
+        if isinstance(value, str):
+            try:
+                load_json(value)
+            except Exception:
+                value = dump_json(value)
+            return value
+
+        return dump_json(value)
 
     def __eq__(self, value) -> QueryString:  # type: ignore[override]
         value = self.clean_value(value)

tests/query/operators/test_json.py

@@ -1,6 +1,7 @@
 from unittest import TestCase
 
 from piccolo.columns import JSONB
+from piccolo.querystring import QueryString
 from piccolo.query.operators.json import GetChildElement, GetElementFromPath
 from piccolo.table import Table
 from tests.base import engines_skip
@@ -50,3 +51,76 @@ def test_query(self):
         )
 
         self.assertListEqual(query_args, [["a", "b"]])
+
+
+class TestJSONQueryString(TestCase):
+
+    def test_clean_value(self):
+        element = GetChildElement(RecordingStudio.facilities, "name")
+
+        # Plain strings should be encoded as JSON
+        self.assertEqual(element.clean_value("hello world"), '"hello world"')
+        self.assertEqual(element.clean_value("foo"), '"foo"')
+
+        # Already valid JSON strings should be preserved
+        self.assertEqual(
+            element.clean_value('{"message": "hello world"}'),
+            '{"message": "hello world"}',
+        )
+        self.assertEqual(element.clean_value('["a", "b"]'), '["a", "b"]')
+        self.assertEqual(
+            element.clean_value('"already quoted"'),
+            '"already quoted"',
+        )
+
+        # Other python types should be dumped to JSON
+        self.assertEqual(
+            element.clean_value({"message": "hello world"}),
+            '{"message": "hello world"}',
+        )
+        self.assertEqual(element.clean_value(["a", "b"]), '["a", "b"]')
+        self.assertEqual(element.clean_value(123), "123")
+        self.assertEqual(element.clean_value(True), "true")
+        self.assertEqual(element.clean_value(None), "null")
+
+        # QueryString should be preserved
+        qs = QueryString("SELECT 1")
+        self.assertEqual(element.clean_value(qs), qs)
+
+    def test_eq_plain_string(self):
+        querystring = (
+            GetChildElement(RecordingStudio.facilities, "name")
+            == "hello world"
+        )
+        sql, query_args = querystring.compile_string(engine_type="postgres")
+        self.assertEqual(
+            sql,
+            '"recording_studio"."facilities" -> $1 = $2',
+        )
+        self.assertListEqual(query_args, ["name", '"hello world"'])
+
+    def test_ne_plain_string(self):
+        querystring = (
+            GetChildElement(RecordingStudio.facilities, "name")
+            != "hello world"
+        )
+        sql, query_args = querystring.compile_string(engine_type="postgres")
+        self.assertEqual(
+            sql,
+            '"recording_studio"."facilities" -> $1 != $2',
+        )
+        self.assertListEqual(query_args, ["name", '"hello world"'])
+
+    def test_eq_valid_json_string(self):
+        querystring = (
+            GetChildElement(RecordingStudio.facilities, "info")
+            == '{"message": "hello world"}'
+        )
+        sql, query_args = querystring.compile_string(engine_type="postgres")
+        self.assertEqual(
+            sql,
+            '"recording_studio"."facilities" -> $1 = $2',
+        )
+        self.assertListEqual(
+            query_args, ["info", '{"message": "hello world"}']
+        )