try:
    from urllib.request import urlopen
except ImportError:
    from urllib import urlopen
import datetime
import multiprocessing

from django.conf import settings
from django.core.urlresolvers import reverse
from django.contrib.sites.models import Site
from django.core.management.base import BaseCommand, CommandError

from core.models import URL, Cron


def request_url(url):
    urlopen("http://{0}{1}".format(
        Site.objects.get_current().domain,
        reverse("run_fn", kwargs={"slug": url.slug})
    ))


class Command(BaseCommand):
    help = "Run the url scripts"
    can_import_settings = True

    def handle(self, *args, **options):
        pool = multiprocessing.Pool(multiprocessing.cpu_count())
        today = int(datetime.date.today().strftime("%s"))
        now = datetime.datetime.now()
        curr_time = int(now.strftime("%s")) - now.second
        mins_passed = int((curr_time - today) / 60.0)
        intervals = Cron.objects.filter(interval__lte=mins_passed)\
                                .values_list('interval', flat=True).\
                                order_by('interval').distinct()
        for interval in intervals:
            if mins_passed % interval == 0 or settings.DEBUG:
                for cron in Cron.objects.filter(interval=interval):
                    url = cron.url
                    pool.apply_async(request_url, (url, ))
        pool.close()
        pool.join()

try:
    from urllib.request import urlopen
except ImportError:
    from urllib import urlopen
import datetime
import multiprocessing

from django.conf import settings
from django.core.urlresolvers import reverse
from django.contrib.sites.models import Site
from django.core.management.base import BaseCommand, CommandError

from core.models import URL, Cron


def request_url(url):
    urlopen("{0}{1}".format(
        Site.objects.get_current().domain,
        reverse("run_fn", kwargs={"slug": url.slug})
    ))


class Command(BaseCommand):
    help = "Run the url scripts"
    can_import_settings = True

    def handle(self, *args, **options):
        pool = multiprocessing.Pool(multiprocessing.cpu_count())
        today = int(datetime.date.today().strftime("%s"))
        now = datetime.datetime.now()
        curr_time = int(now.strftime("%s")) - now.second
        mins_passed = int((curr_time - today) / 60.0)
        intervals = Cron.objects.filter(interval__lte=mins_passed)\
                                .values_list('interval', flat=True).\
                                order_by('interval').distinct()
        for interval in intervals:
            if mins_passed % interval == 0 or settings.DEBUG:
                for cron in Cron.objects.filter(interval=interval):
                    url = cron.url
                    pool.apply_async(request_url, (url, ))
        pool.close()
        pool.join()

Use the site that has scheme also input.