Cleaner approach to HeaderMixin

braces/views/_other.py

@@ -1,5 +1,6 @@
 from django.core.exceptions import ImproperlyConfigured
 from django.shortcuts import redirect
+from django.template.response import TemplateResponse
 from django.views.decorators.cache import cache_control, never_cache
 from django.urls import resolve
 from django.utils.encoding import force_str
@@ -133,27 +134,46 @@ def dispatch(self, request, *args, **kwargs):
         return handler(request, *args, **kwargs)
 
 
+class CustomHeadersTemplateResponse(TemplateResponse):
+    def __init__(self, *args, **kwargs):
+        headers = kwargs.pop("headers", {})
+        headers.update(kwargs.pop("extra_headers", {}))
+        super().__init__(*args, headers=headers, **kwargs)
+
+
 class HeaderMixin:
     """
     Add extra HTTP headers to a response by specifying them in the
     ``headers`` attribute or by overriding the ``get_headers()`` method.
     """
 
     headers = {}
+    response_class = CustomHeadersTemplateResponse
 
     def get_headers(self, request):
         return self.headers
 
+    def render_to_response(self, context, **response_kwargs):
+        """
+        Return a response, using the `response_class` for this view, with a
+        template rendered with the given context.
+        Pass response_kwargs to the constructor of the response class.
+        """
+        response_kwargs.setdefault("extra_headers", self.get_headers(self.request))
+        return super().render_to_response(context, **response_kwargs)
+
     def dispatch(self, request, *args, **kwargs):
         """
         Override this method to customize the way additional headers are
         retrieved.  It is mandatory that the returned value supports the
         ``.items()`` method.
         """
         response = super().dispatch(request, *args, **kwargs)
-        for key, value in self.get_headers(request).items():
-            if key not in response:
-                response[key] = value
+        if not getattr(self, "template_name", None):
+            # No template so probably no `render_to_response` call
+            for key, value in self.get_headers(request).items():
+                if key not in response:
+                    response[key] = value
         return response
 
 

tests/test_access_mixins.py

@@ -744,7 +744,7 @@ def test_https_does_not_redirect(self):
 
 @pytest.mark.django_db
 class TestRecentLoginRequiredMixin(test.TestCase):
-    """ Scenarios requiring a recent login"""
+    """ Scenarios requiring a recent login """
 
     view_class = RecentLoginRequiredView
     recent_view_url = "/recent_login/"

tests/test_other_mixins.py

@@ -588,6 +588,10 @@ def test_existing(self):
         response = self.client.get('/headers/existing/')
         self.assertEqual(response['X-DJANGO-BRACES-EXISTING'], 'value')
 
+    def test_template(self):
+        response = self.client.get('/headers/template/')
+        self.assertEqual(response['X-DJANGO-BRACES-1'], '1')
+
 class TestCacheControlMixin(test.TestCase):
     """Scenarios around controlling cache"""
     def test_cachecontrol_public(self):

tests/urls.py

@@ -118,6 +118,7 @@
     re_path(r'^headers/attribute/$', views.AttributeHeaderView.as_view()),
     re_path(r'^headers/method/$', views.MethodHeaderView.as_view()),
     re_path(r'^headers/existing/$', views.ExistingHeaderView.as_view()),
+    re_path(r'^headers/template/$', views.HeadersWithTemplate.as_view()),
     # CacheControlMixin tests
     re_path(r'^cachecontrol/public/$', views.CacheControlPublicView.as_view()),
     # NeverCacheMixin tests

tests/views.py

@@ -451,6 +451,18 @@ class ExistingHeaderView(views.HeaderMixin, AuxiliaryHeaderView):
         'X-DJANGO-BRACES-EXISTING': 'other value'
     }
 
+class HeadersWithTemplate(views.SetHeadlineMixin, views.HeaderMixin, TemplateView):
+    """
+    View for testing HeaderMixin with a custom TemplateResponse.
+    """
+
+    template_name = "blank.html"
+    headline = "Test headline"
+
+    headers = {
+        "X-DJANGO-BRACES-1": 1
+    }
+
 
 class CacheControlPublicView(views.CacheControlMixin, OkView):
     """A public-cached page with a 60 second timeout"""