from cm.exception import UnauthorizedException 

from django.conf import settings

from django.http import HttpResponseServerError,HttpResponseRedirect

from django.core.urlresolvers import reverse

from urllib import urlencode

class CmMiddleware(object):

    def process_exception(self, request, exception):

        if settings.DEBUG:

            import sys, traceback

            traceback.print_exc()

        if type(exception) == UnauthorizedException:

            if request.user.is_anonymous():

                query = urlencode({'next': request.META['PATH_INFO'], 'q' : request.META['QUERY_STRING'] })

                login_url = reverse('login') + '?'  + query

                return HttpResponseRedirect(login_url)

            else:

                redirect_url = reverse('unauthorized')

                return HttpResponseRedirect(redirect_url)

        raise

    """

        This middleware allows cross-domain XHR using the html5 postMessage API.

    """

    def process_request(self, request):

        if 'HTTP_ACCESS_CONTROL_REQUEST_METHOD' in request.META:

            response = http.HttpResponse()

            response['Access-Control-Allow-Origin']  = '*' 

            return response

        return None

    def process_response(self, request, response):

        # Avoid unnecessary work

        if response.has_header('Access-Control-Allow-Origin'):

            return response

        response['Access-Control-Allow-Origin']  = '*' 

        return response