from django.template import  loader
from django.shortcuts import render_to_response
from registration.models import Registration
from django.http import HttpResponse
from django.template import RequestContext
from django.shortcuts import redirect


def view_login(request,registration_id):
   t = loader.get_template('registration/login.html')
   try:
         registration=Registration.objects.get(pk=registration_id)
   except Registration.DoesNotExist:
         return render_to_response("login.html",{"registration_id":registration_id})

def home(request,registration_id):
    if request.method == "POST":
      username = request.POST.get('user_name')
      password = request.POST.get('password')
      user = authenticate(username=username, password=password)
      if user is not None:
        if user.is_active:
          login(request, user)
        # success
          return render('registration/main_page.html',{'registration_id':registration_id},context_instance=RequestContext(user))
        else:
         #user was not active
           return redirect('q/',context_instance=RequestContext(user))
      else:
        # not a valid user
           return redirect('q/',context_instance=RequestContext(user))
    else:
       # URL was accessed directly
           return redirect('q/',context_instance=RequestContext(user))

<form>
    {% csrf_token %}
    <anything_else>
</form>

return render_to_response("login.html",
    {"registration_id":registration_id},
    context_instance=RequestContext(request))

from django.contrib.auth import authenticate, login

//settings.py
MIDDLEWARE = [
'django.middleware.security.SecurityMiddleware',
'django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.common.CommonMiddleware',
#'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware',
'django.middleware.clickjacking.XFrameOptionsMiddleware',
]

from django.template import RequestContext

context_instance = RequestContext(request)

from django.template.context_processors import csrf

context = {}
context.update(csrf(request))

return render_to_response("login.html",
    {"registration_id":registration_id},
    context=context)

from django.shortcuts import render

return render(request, "login.html", context)