Fixed CsrfMiddleware post processing so that it in the presence of multiple

POST <form>s, only one <input> tag is added with an id, for HTML validity.



git-svn-id: http://code.djangoproject.com/svn/django/trunk@2900 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/contrib/csrf/middleware.py

@@ -9,6 +9,7 @@ from django.conf import settings
 from django.http import HttpResponseForbidden
 import md5
 import re
+import itertools
 
 _ERROR_MSG = "<h1>403 Forbidden</h1><p>Cross Site Request Forgery detected.  Request aborted.</p>"
 
@@ -76,9 +77,16 @@ class CsrfMiddleware(object):
         if csrf_token is not None and \
                 response['Content-Type'].split(';')[0] in _HTML_TYPES:
             
+            # ensure we don't add the 'id' attribute twice (HTML validity)
+            idattributes = itertools.chain(("id='csrfmiddlewaretoken'",), 
+                                            itertools.repeat(''))
+            def add_csrf_field(match):
+                """Returns the matched <form> tag plus the added <input> element"""
+                return match.group() + "<div style='display:none;'>" + \
+                "<input type='hidden' " + idattributes.next() + \
+                " name='csrfmiddlewaretoken' value='" + csrf_token + \
+                "' /></div>"
+
             # Modify any POST forms
-            extra_field = "<div style='display:none;'>" + \
-                "<input type='hidden' id='csrfmiddlewaretoken' name='csrfmiddlewaretoken' value='" + \
-                csrf_token + "' /></div>"
-            response.content = _POST_FORM_RE.sub('\\1' + extra_field, response.content)
+            response.content = _POST_FORM_RE.sub(add_csrf_field, response.content)
         return response