Add _reason_phrase to Response

Improve reason_phrase for error details that are length 1 lists.

Use reason_phrase property rather than non-public attribute

Replace f-strings with format for py35 compatability

Replace missed f-string with format

rest_framework/response.py

@@ -17,9 +17,16 @@ class Response(SimpleTemplateResponse):
     arbitrary media types.
     """
 
-    def __init__(self, data=None, status=None,
-                 template_name=None, headers=None,
-                 exception=False, content_type=None):
+    def __init__(
+        self,
+        data=None,
+        status=None,
+        template_name=None,
+        headers=None,
+        exception=False,
+        content_type=None,
+        reason=None,
+    ):
         """
         Alters the init arguments slightly.
         For example, drop 'template_name', and instead use 'data'.
@@ -41,6 +48,8 @@ class Response(SimpleTemplateResponse):
         self.template_name = template_name
         self.exception = exception
         self.content_type = content_type
+        if reason:
+            self.reason_phrase = "{} ({})".format(self.status_text, reason)
 
         if headers:
             for name, value in headers.items():

rest_framework/views.py

@@ -8,6 +8,7 @@ from django.http import Http404
 from django.http.response import HttpResponseBase
 from django.utils.cache import cc_delim_re, patch_vary_headers
 from django.utils.encoding import smart_str
+from django.utils.translation import gettext_lazy as _
 from django.views.decorators.csrf import csrf_exempt
 from django.views.generic import View
 
@@ -92,11 +93,15 @@ def exception_handler(exc, context):
 
         if isinstance(exc.detail, (list, dict)):
             data = exc.detail
+            reason = _('See response body for full details')
         else:
-            data = {'detail': exc.detail}
+            data = {"detail": exc.detail}
+            reason = str(exc.detail)
+        if isinstance(exc.detail, list) and len(exc.detail) == 1:
+            reason = exc.detail[0]
 
         set_rollback()
-        return Response(data, status=exc.status_code, headers=headers)
+        return Response(data, status=exc.status_code, headers=headers, reason=reason)
 
     return None
 

tests/test_response.py

@@ -32,6 +32,7 @@ class MockTextMediaRenderer(BaseRenderer):
 
 DUMMYSTATUS = status.HTTP_200_OK
 DUMMYCONTENT = 'dummycontent'
+DUMMYREASON = 'dummyreason'
 
 
 def RENDERER_A_SERIALIZER(x):
@@ -78,6 +79,12 @@ class MockViewSettingContentType(APIView):
         return Response(DUMMYCONTENT, status=DUMMYSTATUS, content_type='setbyview')
 
 
+class MockViewSettingReason(APIView):
+
+    def get(self, request, **kwargs):
+        return Response(DUMMYCONTENT, status=DUMMYSTATUS, reason=DUMMYREASON)
+
+
 class JSONView(APIView):
     parser_classes = (JSONParser,)
 
@@ -125,7 +132,8 @@ urlpatterns = [
     path('html1', HTMLView1.as_view()),
     path('html_new_model', HTMLNewModelView.as_view()),
     path('html_new_model_viewset', include(new_model_viewset_router.urls)),
-    path('restframework', include('rest_framework.urls', namespace='rest_framework'))
+    path('restframework', include('rest_framework.urls', namespace='rest_framework')),
+    path('with_reason', MockViewSettingReason.as_view())
 ]
 
 
@@ -283,3 +291,14 @@ class Issue807Tests(TestCase):
         self.assertEqual(resp['Content-Type'], 'text/html; charset=utf-8')
         # self.assertContains(resp, 'Text comes here')
         # self.assertContains(resp, 'Text description.')
+
+
+@override_settings(ROOT_URLCONF='tests.test_response')
+class ReasonPhraseTests(TestCase):
+    def test_reason_is_set(self):
+        resp = self.client.get('/with_reason')
+        self.assertEqual("OK ({})".format(DUMMYREASON), resp.reason_phrase)
+
+    def test_reason_phrase_with_no_reason(self):
+        resp = self.client.get('/')
+        self.assertEqual("OK", resp.reason_phrase)

tests/test_views.py

@@ -1,9 +1,11 @@
 import copy
+import re
 
 from django.test import TestCase
 
 from rest_framework import status
 from rest_framework.decorators import api_view
+from rest_framework.exceptions import ValidationError
 from rest_framework.response import Response
 from rest_framework.settings import APISettings, api_settings
 from rest_framework.test import APIRequestFactory
@@ -12,6 +14,9 @@ from rest_framework.views import APIView
 factory = APIRequestFactory()
 
 JSON_ERROR = 'JSON parse error - Expecting value:'
+STATUS_CODE_400 = 'Bad Request'
+REASON_PHRASE_RE = r"{} \({}.*\)".format(STATUS_CODE_400, JSON_ERROR)
+VALIDATION_ERROR = "Data isn't valid!"
 
 
 class BasicView(APIView):
@@ -39,6 +44,11 @@ class ErrorView(APIView):
         raise Exception
 
 
+class ValidationErrorView(APIView):
+    def get(self, request, *args, **kwargs):
+        raise ValidationError(VALIDATION_ERROR)
+
+
 def custom_handler(exc, context):
     if isinstance(exc, SyntaxError):
         return Response({'error': 'SyntaxError'}, status=400)
@@ -57,6 +67,11 @@ def error_view(request):
     raise Exception
 
 
+@api_view(['GET'])
+def validation_error_view(request):
+    raise ValidationError(VALIDATION_ERROR)
+
+
 def sanitise_json_error(error_dict):
     """
     Exact contents of JSON error messages depend on the installed version
@@ -69,32 +84,44 @@ def sanitise_json_error(error_dict):
 
 
 class ClassBasedViewIntegrationTests(TestCase):
-    def setUp(self):
-        self.view = BasicView.as_view()
 
     def test_400_parse_error(self):
         request = factory.post('/', 'f00bar', content_type='application/json')
-        response = self.view(request)
+        response = BasicView.as_view()(request)
         expected = {
             'detail': JSON_ERROR
         }
         assert response.status_code == status.HTTP_400_BAD_REQUEST
+        assert re.match(REASON_PHRASE_RE, response.reason_phrase)
         assert sanitise_json_error(response.data) == expected
 
+    def test_400_validation_error(self):
+        request = factory.get('/')
+        response = ValidationErrorView.as_view()(request)
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+        assert response.reason_phrase == "{} ({})".format(STATUS_CODE_400, VALIDATION_ERROR)
+        assert response.data == [VALIDATION_ERROR]
+
 
 class FunctionBasedViewIntegrationTests(TestCase):
-    def setUp(self):
-        self.view = basic_view
 
     def test_400_parse_error(self):
         request = factory.post('/', 'f00bar', content_type='application/json')
-        response = self.view(request)
+        response = basic_view(request)
         expected = {
             'detail': JSON_ERROR
         }
         assert response.status_code == status.HTTP_400_BAD_REQUEST
+        assert re.match(REASON_PHRASE_RE, response.reason_phrase)
         assert sanitise_json_error(response.data) == expected
 
+    def test_400_validation_error(self):
+        request = factory.get('/')
+        response = validation_error_view(request)
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+        assert response.reason_phrase == "{} ({})".format(STATUS_CODE_400, VALIDATION_ERROR)
+        assert response.data == [VALIDATION_ERROR]
+
 
 class TestCustomExceptionHandler(TestCase):
     def setUp(self):