Fixed python 3.8.7 compatibility

fastapi/responses.py

@@ -7,17 +7,29 @@
 from starlette.responses import RedirectResponse as RedirectResponse  # noqa
 from starlette.responses import Response as Response  # noqa
 from starlette.responses import StreamingResponse as StreamingResponse  # noqa
-from starlette.responses import UJSONResponse as UJSONResponse  # noqa
 
 try:
     import orjson
 except ImportError:  # pragma: nocover
     orjson = None  # type: ignore
 
+try:
+    import ujson
+except ImportError:  # pragma: nocover
+    ujson = None  # type: ignore
+
 
 class ORJSONResponse(JSONResponse):
     media_type = "application/json"
 
     def render(self, content: Any) -> bytes:
         assert orjson is not None, "orjson must be installed to use ORJSONResponse"
         return orjson.dumps(content)
+
+
+class UJSONResponse(JSONResponse):
+    media_type = "application/json"
+
+    def render(self, content: Any) -> bytes:
+        assert ujson is not None, "ujson must be installed to use UJSONResponse"
+        return ujson.dumps(content, ensure_ascii=False).encode("utf-8")

pyproject.toml

@@ -32,7 +32,7 @@ classifiers = [
     "Topic :: Internet :: WWW/HTTP",
 ]
 requires = [
-    "starlette ==0.13.6",
+    "starlette ==0.14.2",
     "pydantic >=1.0.0,<2.0.0"
 ]
 description-file = "README.md"
@@ -56,6 +56,7 @@ test = [
     "sqlalchemy >=1.3.18,<2.0.0",
     "peewee >=3.13.3,<4.0.0",
     "databases[sqlite] >=0.3.2,<0.4.0",
+    "ujson >=3.0.0,<4.0.0",
     "orjson >=3.2.1,<4.0.0",
     "async_exit_stack >=1.0.1,<2.0.0",
     "async_generator >=1.10,<2.0.0",

tests/test_tutorial/test_custom_response/test_tutorial001.py

@@ -0,0 +1,36 @@
+from fastapi.testclient import TestClient
+
+from docs_src.custom_response.tutorial001 import app
+
+client = TestClient(app)
+
+openapi_schema = {
+    "openapi": "3.0.2",
+    "info": {"title": "FastAPI", "version": "0.1.0"},
+    "paths": {
+        "/items/": {
+            "get": {
+                "responses": {
+                    "200": {
+                        "description": "Successful Response",
+                        "content": {"application/json": {"schema": {}}},
+                    }
+                },
+                "summary": "Read Items",
+                "operationId": "read_items_items__get",
+            }
+        }
+    },
+}
+
+
+def test_openapi_schema():
+    response = client.get("/openapi.json")
+    assert response.status_code == 200, response.text
+    assert response.json() == openapi_schema
+
+
+def test_get_custom_response():
+    response = client.get("/items/")
+    assert response.status_code == 200, response.text
+    assert response.json() == [{"item_id": "Foo"}]