old_contents: from __future__ import unicode_literals
  
  import base32_crockford
  import logging
  
  from django.db.models import F
  from django.http import Http404
  from django.http import HttpResponsePermanentRedirect
  from django.shortcuts import get_object_or_404
  from django.utils.timezone import now
  
  from .models import RedirectURL
  from .utils import add_query_params
  
  
  logger = logging.getLogger(__name__)
  
  
  def redirect(request, url_path):
      """
      """
      try:
          id = base32_crockford.decode(url_path)
      except ValueError as e:
          logger.warning("Error decoding redirect: %s" % e)
          raise Http404
  
      redirect = get_object_or_404(RedirectURL, pk=id)
      RedirectURL.objects.filter(pk=id).update(hits=F('hits') + 1,
                                               last_used=now())
  
      # Inject Google campaign parameters; if any of these
      # are not set, they will be ignored
      utm_params = {'utm_source': redirect.short_url,
                    'utm_campaign': redirect.campaign,
                    'utm_content': redirect.content,
                    'utm_medium': redirect.medium}
      url = add_query_params(redirect.url, utm_params)
  
      return HttpResponsePermanentRedirect(url)
  
new_contents: from __future__ import unicode_literals
  
  import base32_crockford
  import logging
  
  from django.db.models import F
  from django.http import Http404
  from django.http import HttpResponsePermanentRedirect
  from django.shortcuts import get_object_or_404
  from django.utils.timezone import now
  
  from .models import RedirectURL
  from .utils import add_query_params
  
  
  logger = logging.getLogger(__name__)
  
  
  def redirect(request, url_path):
      """
      Given the path component of a short URL, update the URL's
      statistics and redirect the user to the full destination
      URL, including available Google Analytics parameters.
      """
      try:
          id = base32_crockford.decode(url_path)
      except ValueError as e:
          logger.warning("Error decoding redirect '%s': %s" % (url_path, e))
          raise Http404
  
      redirect = get_object_or_404(RedirectURL, pk=id)
      RedirectURL.objects.filter(pk=id).update(hits=F('hits') + 1,
                                               last_used=now())
  
      # Inject Google campaign parameters; if any of these
      # are not set, they will be ignored
      utm_params = {'utm_source': redirect.short_url,
                    'utm_campaign': redirect.campaign,
                    'utm_content': redirect.content,
                    'utm_medium': redirect.medium}
      url = add_query_params(redirect.url, utm_params)
  
      return HttpResponsePermanentRedirect(url)
  
subject: Improve comment and logging text