1 from django import http, template

     2 from django.conf import settings

     3 from django.contrib.auth.models import User

     4 from django.contrib.auth import authenticate, login

     5 from django.shortcuts import render_to_response

     6 from django.utils.translation import gettext_lazy

     7 import base64, datetime, md5

     8 import cPickle as pickle

     9 

    10 ERROR_MESSAGE = gettext_lazy("Please enter a correct username and password. Note that both fields are case-sensitive.")

    11 LOGIN_FORM_KEY = 'this_is_the_login_form'

    12 

    13 def _display_login_form(request, error_message=''):

    14     request.session.set_test_cookie()

    15     if request.POST and request.POST.has_key('post_data'):

    16         # User has failed login BUT has previously saved post data.

    17         post_data = request.POST['post_data']

    18     elif request.POST:

    19         # User's session must have expired; save their post data.

    20         post_data = _encode_post_data(request.POST)

    21     else:

    22         post_data = _encode_post_data({})

    23     return render_to_response('admin/login.html', {

    24         'title': _('Log in'),

    25         'app_path': request.path,

    26         'post_data': post_data,

    27         'error_message': error_message

    28     }, context_instance=template.RequestContext(request))

    29 

    30 def _encode_post_data(post_data):

    31     pickled = pickle.dumps(post_data)

    32     pickled_md5 = md5.new(pickled + settings.SECRET_KEY).hexdigest()

    33     return base64.encodestring(pickled + pickled_md5)

    34 

    35 def _decode_post_data(encoded_data):

    36     encoded_data = base64.decodestring(encoded_data)

    37     pickled, tamper_check = encoded_data[:-32], encoded_data[-32:]

    38     if md5.new(pickled + settings.SECRET_KEY).hexdigest() != tamper_check:

    39         from django.core.exceptions import SuspiciousOperation

    40         raise SuspiciousOperation, "User may have tampered with session cookie."

    41     return pickle.loads(pickled)

    42 

    43 def staff_member_required(view_func):

    44     """

    45     Decorator for views that checks that the user is logged in and is a staff

    46     member, displaying the login page if necessary.

    47     """

    48     def _checklogin(request, *args, **kwargs):

    49         if request.user.is_authenticated() and request.user.is_staff:

    50             # The user is valid. Continue to the admin page.

    51             if request.POST.has_key('post_data'):

    52                 # User must have re-authenticated through a different window

    53                 # or tab.

    54                 request.POST = _decode_post_data(request.POST['post_data'])

    55             return view_func(request, *args, **kwargs)

    56 

    57         assert hasattr(request, 'session'), "The Django admin requires session middleware to be installed. Edit your MIDDLEWARE_CLASSES setting to insert 'django.contrib.sessions.middleware.SessionMiddleware'."

    58 

    59         # If this isn't already the login page, display it.

    60         if not request.POST.has_key(LOGIN_FORM_KEY):

    61             if request.POST:

    62                 message = _("Please log in again, because your session has expired. Don't worry: Your submission has been saved.")

    63             else:

    64                 message = ""

    65             return _display_login_form(request, message)

    66 

    67         # Check that the user accepts cookies.

    68         if not request.session.test_cookie_worked():

    69             message = _("Looks like your browser isn't configured to accept cookies. Please enable cookies, reload this page, and try again.")

    70             return _display_login_form(request, message)

    71 

    72         # Check the password.

    73         username = request.POST.get('username', None)

    74         password = request.POST.get('password', None)

    75         user = authenticate(username=username, password=password)

    76         if user is None:

    77             message = ERROR_MESSAGE

    78             if '@' in username:

    79                 # Mistakenly entered e-mail address instead of username? Look it up.

    80                 try:

    81                     user = User.objects.get(email=username)

    82                 except User.DoesNotExist:

    83                     message = _("Usernames cannot contain the '@' character.")

    84                 else:

    85                     message = _("Your e-mail address is not your username. Try '%s' instead.") % user.username

    86             return _display_login_form(request, message)

    87 

    88         # The user data is correct; log in the user in and continue.

    89         else:

    90             if user.is_active and user.is_staff:

    91                 login(request, user)

    92                 # TODO: set last_login with an event.

    93                 user.last_login = datetime.datetime.now()

    94                 user.save()

    95                 if request.POST.has_key('post_data'):

    96                     post_data = _decode_post_data(request.POST['post_data'])

    97                     if post_data and not post_data.has_key(LOGIN_FORM_KEY):

    98                         # overwrite request.POST with the saved post_data, and continue

    99                         request.POST = post_data

   100                         request.user = user

   101                         return view_func(request, *args, **kwargs)

   102                     else:

   103                         request.session.delete_test_cookie()

   104                         return http.HttpResponseRedirect(request.path)

   105             else:

   106                 return _display_login_form(request, ERROR_MESSAGE)

   107 

   108     return _checklogin