From 16945f0e9c57aeabadb6f2e2f150a2687455be40 Mon Sep 17 00:00:00 2001
From: Raphael Michel <mail@raphaelmichel.de>
Date: Sat, 7 Nov 2015 14:18:06 +0100
Subject: [PATCH] Fixed #25695 -- Added template_name parameter to
 csrf_failure() view.

---
 django/views/csrf.py                | 15 +++++++++++---
 docs/ref/settings.txt               |  9 ++++++++
 docs/releases/1.10.txt              |  4 +++-
 tests/view_tests/tests/test_csrf.py | 32 ++++++++++++++++++++++++++++-
 4 files changed, 55 insertions(+), 5 deletions(-)

diff --git a/django/views/csrf.py b/django/views/csrf.py
index 9ab9c44171..7d5f4e113e 100644
--- a/django/views/csrf.py
+++ b/django/views/csrf.py
@@ -1,6 +1,6 @@
 from django.conf import settings
 from django.http import HttpResponseForbidden
-from django.template import Context, Engine
+from django.template import Context, Engine, TemplateDoesNotExist, loader
 from django.utils.translation import ugettext as _
 from django.utils.version import get_docs_version
 
@@ -95,14 +95,14 @@ CSRF_FAILURE_TEMPLATE = """
 </body>
 </html>
 """
+CSRF_FAILURE_TEMPLATE_NAME = "403_csrf.html"
 
 
-def csrf_failure(request, reason=""):
+def csrf_failure(request, reason="", template_name=CSRF_FAILURE_TEMPLATE_NAME):
     """
     Default view used when request fails CSRF protection
     """
     from django.middleware.csrf import REASON_NO_REFERER, REASON_NO_CSRF_COOKIE
-    t = Engine().from_string(CSRF_FAILURE_TEMPLATE)
     c = Context({
         'title': _("Forbidden"),
         'main': _("CSRF verification failed. Request aborted."),
@@ -131,4 +131,13 @@ def csrf_failure(request, reason=""):
         'docs_version': get_docs_version(),
         'more': _("More information is available with DEBUG=True."),
     })
+    try:
+        t = loader.get_template(template_name)
+    except TemplateDoesNotExist:
+        if template_name == CSRF_FAILURE_TEMPLATE_NAME:
+            # If the default template doesn't exist, use the string template.
+            t = Engine().from_string(CSRF_FAILURE_TEMPLATE)
+        else:
+            # Raise if a developer-specified template doesn't exist.
+            raise
     return HttpResponseForbidden(t.render(c), content_type='text/html')
diff --git a/docs/ref/settings.txt b/docs/ref/settings.txt
index ff3d420433..92a2ad4980 100644
--- a/docs/ref/settings.txt
+++ b/docs/ref/settings.txt
@@ -385,6 +385,15 @@ where ``reason`` is a short message (intended for developers or logging, not for
 end users) indicating the reason the request was rejected.  See
 :doc:`/ref/csrf`.
 
+``django.views.csrf.csrf_failure()`` accepts an additional ``template_name``
+parameter that defaults to ``'403_csrf.html'``. If a template with that name
+exists, it will be used to render the page.
+
+.. versionchanged:: 1.10
+
+   The ``template_name`` parameter and the behavior of searching for a template
+   called ``403_csrf.html`` were added to ``csrf_failure()``.
+
 .. setting:: CSRF_HEADER_NAME
 
 CSRF_HEADER_NAME
diff --git a/docs/releases/1.10.txt b/docs/releases/1.10.txt
index 6dbe0362b9..1e51c1dec9 100644
--- a/docs/releases/1.10.txt
+++ b/docs/releases/1.10.txt
@@ -114,7 +114,9 @@ Cache
 CSRF
 ^^^^
 
-* ...
+* The default :setting:`CSRF_FAILURE_VIEW`, ``views.csrf.csrf_failure()`` now
+  accepts an optional ``template_name`` parameter, defaulting to
+  ``'403_csrf.html'``, to control the template used to render the page.
 
 Database backends
 ^^^^^^^^^^^^^^^^^
diff --git a/tests/view_tests/tests/test_csrf.py b/tests/view_tests/tests/test_csrf.py
index f6531b882c..f595652978 100644
--- a/tests/view_tests/tests/test_csrf.py
+++ b/tests/view_tests/tests/test_csrf.py
@@ -1,5 +1,9 @@
-from django.test import Client, SimpleTestCase, override_settings
+from django.template import TemplateDoesNotExist
+from django.test import (
+    Client, RequestFactory, SimpleTestCase, override_settings,
+)
 from django.utils.translation import override
+from django.views.csrf import CSRF_FAILURE_TEMPLATE_NAME, csrf_failure
 
 
 @override_settings(ROOT_URLCONF="view_tests.urls")
@@ -70,3 +74,29 @@ class CsrfViewTests(SimpleTestCase):
         """
         response = self.client.post('/')
         self.assertContains(response, "Forbidden", status_code=403)
+
+    @override_settings(TEMPLATES=[{
+        'BACKEND': 'django.template.backends.django.DjangoTemplates',
+        'OPTIONS': {
+            'loaders': [
+                ('django.template.loaders.locmem.Loader', {
+                    CSRF_FAILURE_TEMPLATE_NAME: 'Test template for CSRF failure'
+                }),
+            ],
+        },
+    }])
+    def test_custom_template(self):
+        """
+        A custom CSRF_FAILURE_TEMPLATE_NAME is used.
+        """
+        response = self.client.post('/')
+        self.assertContains(response, "Test template for CSRF failure", status_code=403)
+
+    def test_custom_template_does_not_exist(self):
+        """
+        An exception is raised if a nonexistent template is supplied.
+        """
+        factory = RequestFactory()
+        request = factory.post('/')
+        with self.assertRaises(TemplateDoesNotExist):
+            csrf_failure(request, template_name="nonexistent.html")