Fix empty multipart body form fields

ninja/params/models.py

@@ -183,7 +183,11 @@ def get_request_data(
         for name, annotation in cls.__ninja_body_params__.items():
             if name in request.POST:
                 data = request.POST[name]
-                if annotation is str and data[0] != '"' and data[-1] != '"':
+                if (
+                    annotation is str
+                    and not data.startswith('"')
+                    and not data.endswith('"')
+                ):
                     data = f'"{data}"'
                 req.body = data.encode()
                 results[name] = get_request_data(req, api, path_params)

tests/test_forms_and_files.py

@@ -1,6 +1,6 @@
 from django.core.files.uploadedfile import SimpleUploadedFile
 
-from ninja import File, Form, NinjaAPI, UploadedFile
+from ninja import Body, File, Form, NinjaAPI, UploadedFile
 from ninja.testing import TestClient
 
 api = NinjaAPI()
@@ -16,6 +16,15 @@ def str_and_file(
     return {"title": title, "data": file.read().decode()}
 
 
+@api.post("/str_body_and_file")
+def str_body_and_file(
+    request,
+    title: str = Body(...),
+    file: UploadedFile = File(...),
+):
+    return {"title": title, "data": file.read().decode()}
+
+
 client = TestClient(api)
 
 
@@ -57,3 +66,14 @@ def test_files():
         },
         "required": True,
     }
+
+
+def test_empty_multipart_body_field():
+    file = SimpleUploadedFile("test.txt", b"data123")
+    response = client.post(
+        "/str_body_and_file",
+        FILES={"file": file},
+        POST={"title": ""},
+    )
+    assert response.status_code == 200
+    assert response.json() == {"title": "", "data": "data123"}