Added django.contrib.admin, with a staff_member_required decorator and code from AdminUserRequired middleware. Refs #627

git-svn-id: http://code.djangoproject.com/svn/django/trunk@921 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/contrib/admin/views/decorators.py

@@ -0,0 +1,100 @@
+from django.core.extensions import DjangoContext, render_to_response
+from django.conf.settings import SECRET_KEY
+from django.models.auth import users
+from django.utils import httpwrappers
+import base64, md5
+import cPickle as pickle
+
+ERROR_MESSAGE = "Please enter a correct username and password. Note that both fields are case-sensitive."
+LOGIN_FORM_KEY = 'this_is_the_login_form'
+
+def _display_login_form(request, error_message=''):
+    request.session.set_test_cookie()
+    if request.POST and request.POST.has_key('post_data'):
+        # User has failed login BUT has previously saved post data.
+        post_data = request.POST['post_data']
+    elif request.POST:
+        # User's session must have expired; save their post data.
+        post_data = _encode_post_data(request.POST)
+    else:
+        post_data = _encode_post_data({})
+    return render_to_response('admin/login', {
+        'title': 'Log in',
+        'app_path': request.path,
+        'post_data': post_data,
+        'error_message': error_message
+    }, context_instance=DjangoContext(request))
+
+def _encode_post_data(post_data):
+    pickled = pickle.dumps(post_data)
+    pickled_md5 = md5.new(pickled + SECRET_KEY).hexdigest()
+    return base64.encodestring(pickled + pickled_md5)
+
+def _decode_post_data(encoded_data):
+    encoded_data = base64.decodestring(encoded_data)
+    pickled, tamper_check = encoded_data[:-32], encoded_data[-32:]
+    if md5.new(pickled + SECRET_KEY).hexdigest() != tamper_check:
+        from django.core.exceptions import SuspiciousOperation
+        raise SuspiciousOperation, "User may have tampered with session cookie."
+    return pickle.loads(pickled)
+
+def staff_member_required(view_func):
+    """
+    Decorator for views that checks that the user is logged in and is a staff
+    member, displaying the login page if necessary.
+    """
+    def _checklogin(request, *args, **kwargs):
+        if not request.user.is_anonymous() and request.user.is_staff:
+            # The user is valid. Continue to the admin page.
+            return view_func(request, *args, **kwargs)
+
+        assert hasattr(request, 'session'), "The Django admin requires session middleware to be installed. Edit your MIDDLEWARE_CLASSES setting to insert 'django.middleware.sessions.SessionMiddleware'."
+
+        # If this isn't already the login page, display it.
+        if not request.POST.has_key(LOGIN_FORM_KEY):
+            if request.POST:
+                message = "Please log in again, because your session has expired. "\
+                          "Don't worry: Your submission has been saved."
+            else:
+                message = ""
+            return _display_login_form(request, message)
+
+        # Check that the user accepts cookies.
+        if not request.session.test_cookie_worked():
+            message = "Looks like your browser isn't configured to accept cookies. Please enable cookies, reload this page, and try again."
+            return _display_login_form(request, message)
+
+        # Check the password.
+        username = request.POST.get('username', '')
+        try:
+            user = users.get_object(username__exact=username, is_staff__exact=True)
+        except users.UserDoesNotExist:
+            message = ERROR_MESSAGE
+            if '@' in username:
+                # Mistakenly entered e-mail address instead of username? Look it up.
+                try:
+                    user = users.get_object(email__exact=username)
+                except users.UserDoesNotExist:
+                    message = "Usernames cannot contain the '@' character."
+                else:
+                    message = "Your e-mail address is not your username. Try '%s' instead." % user.username
+            return _display_login_form(request, message)
+
+        # The user data is correct; log in the user in and continue.
+        else:
+            if user.check_password(request.POST.get('password', '')):
+                request.session[users.SESSION_KEY] = user.id
+                if request.POST.has_key('post_data'):
+                    post_data = _decode_post_data(request.POST['post_data'])
+                    if post_data and not post_data.has_key(LOGIN_FORM_KEY):
+                        # overwrite request.POST with the saved post_data, and continue
+                        request.POST = post_data
+                        request.user = user
+                        return view_func(request, *args, **kwargs)
+                    else:
+                        request.session.delete_test_cookie()
+                        return httpwrappers.HttpResponseRedirect(request.path)
+            else:
+                return _display_login_form(request, ERROR_MESSAGE)
+
+    return _checklogin