diff --git a/django/contrib/csrf/middleware.py b/django/contrib/csrf/middleware.py
index 7da79ba59c..6f818fc93c 100644
--- a/django/contrib/csrf/middleware.py
+++ b/django/contrib/csrf/middleware.py
@@ -7,6 +7,10 @@ against request forgeries from other sites.
import re
import itertools
+try:
+ from functools import wraps
+except ImportError:
+ from django.utils.functional import wraps # Python 2.3, 2.4 fallback.
from django.conf import settings
from django.http import HttpResponseForbidden
@@ -30,6 +34,12 @@ class CsrfViewMiddleware(object):
"""
def process_view(self, request, callback, callback_args, callback_kwargs):
if request.method == 'POST':
+ if getattr(callback, 'csrf_exempt', False):
+ return None
+
+ if request.is_ajax():
+ return None
+
try:
session_id = request.COOKIES[settings.SESSION_COOKIE_NAME]
except KeyError:
@@ -107,3 +117,14 @@ class CsrfMiddleware(CsrfViewMiddleware, CsrfResponseMiddleware):
and CsrfResponseMiddleware which can be used independently.
"""
pass
+
+def csrf_exempt(view_func):
+ """
+ Marks a view function as being exempt from the CSRF checks
+ """
+ def wrapped_view(*args, **kwargs):
+ return view_func(*args, **kwargs)
+ # We could just do view.csrf_exempt = True, but decorators are
+ # nicer if they don't have side-effects.
+ wrapped_view.csrf_exempt = True
+ return wraps(view_func)(wrapped_view)
diff --git a/django/contrib/csrf/tests.py b/django/contrib/csrf/tests.py
index 071099ea91..b9f402e1a9 100644
--- a/django/contrib/csrf/tests.py
+++ b/django/contrib/csrf/tests.py
@@ -2,10 +2,19 @@
from django.test import TestCase
from django.http import HttpRequest, HttpResponse, HttpResponseForbidden
-from django.contrib.csrf.middleware import CsrfMiddleware, _make_token
+from django.contrib.csrf.middleware import CsrfMiddleware, _make_token, csrf_exempt
from django.conf import settings
+def post_form_response():
+ resp = HttpResponse(content="""
+
+""", mimetype="text/html")
+ return resp
+
+def test_view(request):
+ return post_form_response()
+
class CsrfMiddlewareTest(TestCase):
_session_id = "1"
@@ -34,10 +43,7 @@ class CsrfMiddlewareTest(TestCase):
return req
def _get_post_form_response(self):
- resp = HttpResponse(content="""
-
-""", mimetype="text/html")
- return resp
+ return post_form_response()
def _get_new_session_response(self):
resp = self._get_post_form_response()
@@ -48,8 +54,7 @@ class CsrfMiddlewareTest(TestCase):
self.assertContains(response, "name='csrfmiddlewaretoken' value='%s'" % _make_token(self._session_id))
def get_view(self):
- def dummyview(request):
- return self._get_post_form_response()
+ return test_view
# Check the post processing
def test_process_response_no_session(self):
@@ -109,3 +114,21 @@ class CsrfMiddlewareTest(TestCase):
req = self._get_POST_session_request_with_token()
req2 = CsrfMiddleware().process_view(req, self.get_view(), (), {})
self.assertEquals(None, req2)
+
+ def test_process_request_session_no_token_exempt_view(self):
+ """
+ Check that if a session is present and no token, but the csrf_exempt
+ decorator has been applied to the view, the middleware lets it through
+ """
+ req = self._get_POST_session_request()
+ req2 = CsrfMiddleware().process_view(req, csrf_exempt(self.get_view()), (), {})
+ self.assertEquals(None, req2)
+
+ def test_ajax_exemption(self):
+ """
+ Check the AJAX requests are automatically exempted.
+ """
+ req = self._get_POST_session_request()
+ req.META['HTTP_X_REQUESTED_WITH'] = 'XMLHttpRequest'
+ req2 = CsrfMiddleware().process_view(req, self.get_view(), (), {})
+ self.assertEquals(None, req2)
diff --git a/docs/ref/contrib/csrf.txt b/docs/ref/contrib/csrf.txt
index cf0fe8a3bf..feb91f65d8 100644
--- a/docs/ref/contrib/csrf.txt
+++ b/docs/ref/contrib/csrf.txt
@@ -26,7 +26,18 @@ Add the middleware ``'django.contrib.csrf.middleware.CsrfMiddleware'`` to
your list of middleware classes, :setting:`MIDDLEWARE_CLASSES`. It needs to process
the response after the SessionMiddleware, so must come before it in the
list. It also must process the response before things like compression
-happen to the response, so it must come after GZipMiddleware in the list.
+happen to the response, so it must come after GZipMiddleware in the
+list.
+
+Exceptions
+----------
+
+To manually exclude a view function from being handled by the
+CsrfMiddleware, you can use the ``csrf_exempt`` decorator (found in
+the ``django.contrib.csrf.middleware`` module).
+
+AJAX requests sent with "X-Requested-With: XMLHttpRequest" are
+automatically exempt (see below).
How it works
============
@@ -59,6 +70,18 @@ The Content-Type is checked before modifying the response, and only
pages that are served as 'text/html' or 'application/xml+xhtml'
are modified.
+AJAX requests sent with "X-Requested-With: XMLHttpRequest", as done by
+many AJAX toolkits, are detected and automatically excepted from this
+mechanism. This is because in the context of a browser, this header
+can only be added by using XMLHttpRequest, and browsers already
+implement a same-domain policy for XMLHttpRequest. This is not secure
+if you do not trust content within the same domain or sub-domains.
+
+The above two functions of ``CsrfMiddleware`` are split between two
+classes: ``CsrfResponseMiddleware`` and ``CsrfViewMiddleware``
+respectively. This allows the individual components to be used and/or
+replaced instead of using ``CsrfMiddleware``.
+
.. _9.1.1 Safe Methods, HTTP 1.1, RFC 2616: http://www.w3.org/Protocols/rfc2616/rfc2616-sec9.html
Limitations
@@ -73,4 +96,4 @@ it sends fragments of HTML in JavaScript document.write statements)
you might bypass the filter that adds the hidden field to the form,
in which case form submission will always fail. It may still be possible
to use the middleware, provided you can find some way to get the
-CSRF token and ensure that is included when your form is submitted.
\ No newline at end of file
+CSRF token and ensure that is included when your form is submitted.