Re: Issue with mongo in Django

Hi Ashish, I know it's been long since you worked on this problem. I am not able to get past this error despite trying these solution. Is there a permanent sort of fix for this problem? could you please help me out. Thanks!

On Wednesday, June 24, 2015 at 3:43:45 AM UTC+5:30, Ashish Khatkar wrote:

Hi,

Today I was trying to do user authentication with Django + MongoDB. I was constantly getting "Metadict object has no attribute pk" error. I searched for the fix but nothing helped. In the end, I read the implementation of login function and changed request.session[SESSION_KEY] = user._meta.pk.value_to_string(user) to request.session[SESSION_KEY] = user.id in django/contrib/auth/__init__.py and correspondingly changed return int(value) line no 947 to return value in django/db/models/fields/__init__.py as automated primary key for mongo db is a hexadecimal string. It worked this way.

Is there any other way to achieve same thing ? If not should I create a PR to fix this.

My settings.py

"""

Django settings for testApp project.

Generated by 'django-admin startproject' using Django 1.8.2.

For more information on this file, see

https://docs.djangoproject.com/en/1.8/topics/settings/

For the full list of settings and their values, see

https://docs.djangoproject.com/en/1.8/ref/settings/

"""

# Build paths inside the project like this: os.path.join(BASE_DIR, ...)

import os

BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))

# Quick-start development settings - unsuitable for production

# See https://docs.djangoproject.com/en/1.8/howto/deployment/checklist/

# SECURITY WARNING: keep the secret key used in production secret!

SECRET_KEY = ')s&uno-o3x)v^1-2bjt4o8*(sf^8zw42+#tvm(&km&fs+39x!5'

# SECURITY WARNING: don't run with debug turned on in production!

DEBUG = True

ALLOWED_HOSTS = ["localhost"]

# Application definition

INSTALLED_APPS = (

  'django.contrib.admin',

  'django.contrib.auth',

  'django.contrib.contenttypes',

  'django.contrib.sessions',

  'django.contrib.messages',

  'django.contrib.staticfiles',

  'meriApp',

)

MIDDLEWARE_CLASSES = (

  'django.contrib.sessions.middleware.SessionMiddleware',

  'django.middleware.common.CommonMiddleware',

  'django.middleware.csrf.CsrfViewMiddleware',

  'django.contrib.auth.middleware.AuthenticationMiddleware',

  'django.contrib.auth.middleware.SessionAuthenticationMiddleware',

  'django.contrib.messages.middleware.MessageMiddleware',

  'django.middleware.clickjacking.XFrameOptionsMiddleware',

  'django.middleware.security.SecurityMiddleware',

)

ROOT_URLCONF = 'testApp.urls'

TEMPLATES = [

  {

      'BACKEND': 'django.template.backends.django.DjangoTemplates',

      'DIRS': [],

      'APP_DIRS': True,

      'OPTIONS': {

          'context_processors': [

              'django.template.context_processors.debug',

              'django.template.context_processors.request',

              'django.contrib.auth.context_processors.auth',

              'django.contrib.messages.context_processors.messages',

          ],

      },

  },

]

WSGI_APPLICATION = 'testApp.wsgi.application'

# Database

# https://docs.djangoproject.com/en/1.8/ref/settings/#databases

# DATABASES = {

#     'default': {

#         'ENGINE': 'django.db.backends.sqlite3',

#         'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),

#     }

# }

# Internationalization

# https://docs.djangoproject.com/en/1.8/topics/i18n/

LANGUAGE_CODE = 'en-us'

TIME_ZONE = 'Asia/Kolkata'

USE_I18N = True

USE_L10N = True

USE_TZ = True

# Static files (CSS, JavaScript, Images)

# https://docs.djangoproject.com/en/1.8/howto/static-files/

STATIC_URL = '/static/'

LOGIN_URL = ''

LOGIN_REDIRECT_URL = '/meriApp/'

import mongoengine

DATABASES = {

  'default': {

      'ENGINE': 'django.db.backends.dummy',

  },

}

SESSION_ENGINE = 'mongoengine.django.sessions' # optional

# _MONGODB_USER = ''

# _MONGODB_PASSWD = ''

# _MONGODB_HOST = ''

_MONGODB_NAME = 'test'

# _MONGODB_DATABASE_HOST = \

#     'mongodb://%s:%s@%s/%s' \

#     % (_MONGODB_USER, _MONGODB_PASSWD, _MONGODB_HOST, _MONGODB_NAME)

# mongoengine.connect(_MONGODB_NAME, host=_MONGODB_DATABASE_HOST)

mongoengine.connect(_MONGODB_NAME)

AUTHENTICATION_BACKENDS = (

  'mongoengine.django.auth.MongoEngineBackend',

)

This is the view with which I am authenticating :

Enter code here...@csrf_protect

def login_view(request):

  if request.method == 'GET':

            return render_to_response('index.html', context_instance=RequestContext(request))

      elif request.method == 'POST':

         try:

                   username = request.POST['email']

                       password = request.POST['password']

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

                     if user.check_password(password):

                              user.backend = 'mongoengine.django.auth.MongoEngineBackend'

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

                                login(request, user)

                           return HttpResponseRedirect('/meriApp/dashboard')

                      else:

                          return render_to_response('index.html', {'msg' : "Invalid Email/Password"}, context_instance=RequestContext(request))

          except DoesNotExist:

                   return render_to_response('index.html', {'msg' : "This user doesn't exist"}, context_instance=RequestContext(request))

Changes I did in django/contrib/auth/__init__.py :

try:

       request.session[SESSION_KEY] = user._meta.pk.value_to_string(user)

   except Exception:

       request.session[SESSION_KEY] = user.id

Changes I did in django/contrib/auth/__init__.py :

try: return int(value) except ValueError: try: # As mongoDB id is hex string, try to parse it. # If it raises exception than raise validation error # else return the hex string int(value, 16) return value except ValueError: raise exceptions.ValidationError( self.error_messages['invalid'], code='invalid', params={'value': value}, ) except (ValueError, TypeError): raise exceptions.ValidationError( self.error_messages['invalid'], code='invalid', params={'value': value}, )

Now if I don't perform these changes, I get metadict object has no attribute pk. Which i resolved by adding try except. Similarly to resolve validation error i added try except block there.

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