code: def view(request, message_id, form_class=ComposeForm, quote_helper=format_quote,
          subject_template=_(u"Re: %(subject)s"),
          template_name='django_messages/view.html'):
      
      user = request.user
      now = timezone.now()
      message = get_object_or_404(Message, id=message_id)
      if (message.sender != user) and (message.recipient != user):
          raise Http404
      if message.read_at is None and message.recipient == user:
          message.read_at = now
          message.save()
  
      context = {'message': message, 'reply_form': None}
      if message.recipient == user:
          form = form_class(initial={
              'body': quote_helper(message.sender, message.body),
              'subject': subject_template % {'subject': message.subject},
              'recipient': [message.sender,]
              })
          context['reply_form'] = form
      return render(request, template_name, context)
docs: Shows a single message.``message_id`` argument is required.
      The user is only allowed to see the message, if he is either
      the sender or the recipient. If the user is not allowed a 404
      is raised.
      If the user is the recipient and the message is unread
      ``read_at`` is set to the current datetime.
      If the user is the recipient a reply form will be added to the
      tenplate context, otherwise 'reply_form' will be None.