handle NoContent response in operation validation

connexion/apis/abstract.py

@@ -285,6 +285,9 @@ def encode_body(cls, body, mimetype=None):
         if json_encode or not is_string(body):
             if isinstance(body, six.binary_type):
                 body = decode(body)
+            """if body is empty transform it to object."""
+            if body == "":
+                body = {}
             body = cls.jsonifier.dumps(body)
         if isinstance(body, six.text_type):
             body = body.encode("UTF-8")

connexion/apis/flask_api.py

@@ -7,7 +7,6 @@
 
 from connexion.apis import flask_utils
 from connexion.apis.abstract import AbstractAPI
-from connexion.decorators.produces import NoContent
 from connexion.handlers import AuthErrorHandler
 from connexion.lifecycle import ConnexionRequest, ConnexionResponse
 from connexion.operations.validation import validate_operation_output
@@ -159,12 +158,8 @@ def _build_flask_response(cls, mimetype=None, content_type=None,
 
             flask_response.status_code = status_code
 
-        if data is not None and data is not NoContent:
-            data = cls.encode_body(data, mimetype)
-            flask_response.set_data(data)
-
-        elif data is NoContent:
-            flask_response.set_data('')
+        data = cls.encode_body(data, mimetype)
+        flask_response.set_data(data)
 
         return flask_response
 
@@ -180,6 +175,7 @@ def _response_from_handler(cls, response, mimetype):
             return flask.current_app.make_response(response)
 
         body, status_code, headers = validate_operation_output(response)
+
         return cls._build_flask_response(
             mimetype=mimetype,
             headers=headers,

connexion/operations/validation.py

@@ -1,16 +1,21 @@
 import six
 
+from connexion.decorators.produces import NoContent
 from connexion.utils import normalize_tuple
 
 BODY_TYPES = (six.text_type, six.binary_type, dict, list)
 
 
 def validate_operation_output(response):
     """Will validate the format returned by a handler."""
-    if isinstance(response, BODY_TYPES):
+    if isinstance(response, BODY_TYPES) or response == NoContent:
         response = (response, )
+
     body, status, headers = normalize_tuple(response, 3)
-    if not isinstance(body, BODY_TYPES):
+
+    if body == NoContent:
+        body = b""
+    elif not isinstance(body, BODY_TYPES):
         raise ValueError(
             "first returned value has to be {}, got {}".format(
                 BODY_TYPES, type(body)

tests/api/test_abstract.py

@@ -12,6 +12,7 @@
     (b"test", "text/plain", b"test"),
     ("test", "application/json", b'"test"\n'),
     (b"test", "application/json", b'"test"\n'),
+    ("", "application/json", b"{}\n")
 ])
 def test_encode_body(body, mimetype, expected):
     """Test the body encoding.

tests/operations/test_op_validation.py

@@ -1,4 +1,5 @@
 import pytest
+from connexion.decorators.produces import NoContent
 from connexion.operations.validation import (BODY_TYPES,
                                              validate_operation_output)
 
@@ -16,3 +17,12 @@ def test_validate_operation_output(output):
     assert isinstance(body, BODY_TYPES)
     assert isinstance(status, int) or status is None
     assert isinstance(headers, dict) or headers is None
+
+
+@pytest.mark.parametrize("output", [
+    NoContent,
+    (NoContent,)
+])
+def test_validate_operation_no_content(output):
+    body, _, _ = validate_operation_output(output)
+    assert body == b""