# dokumentasi Django 2.2.9.dev20191202104323

# Kode sumber untuk django.contrib.sitemaps

    from urllib.parse import urlencode
    from urllib.request import urlopen

    from django.apps import apps as django_apps
    from django.conf import settings
    from django.core import paginator
    from django.core.exceptions import ImproperlyConfigured
    from django.urls import NoReverseMatch, reverse
    from django.utils import translation

    PING_URL = "https://www.google.com/webmasters/tools/ping"

    class SitemapNotFound(Exception):
        pass

    def ping_google(sitemap_url=None, ping_url=PING_URL, sitemap_uses_https=True):
        """
        Alert Google that the sitemap for the current site has been updated.
        If sitemap_url is provided, it should be an absolute path to the sitemap
        for this site -- e.g., '/sitemap.xml'. If sitemap_url is not provided, this
        function will attempt to deduce it by using urls.reverse().
        """
        sitemap_full_url = _get_sitemap_full_url(sitemap_url, sitemap_uses_https)
        params = urlencode({'sitemap': sitemap_full_url})
        urlopen('%s?%s' % (ping_url, params))

    def _get_sitemap_full_url(sitemap_url, sitemap_uses_https=True):
        if not django_apps.is_installed('django.contrib.sites'):
            raise ImproperlyConfigured("ping_google requires django.contrib.sites, which isn't installed.")

        if sitemap_url is None:
            try:
                # First, try to get the "index" sitemap URL.
                sitemap_url = reverse('django.contrib.sitemaps.views.index')
            except NoReverseMatch:
                try:
                    # Next, try for the "global" sitemap URL.
                    sitemap_url = reverse('django.contrib.sitemaps.views.sitemap')
                except NoReverseMatch:
                    pass

        if sitemap_url is None:
            raise SitemapNotFound("You didn't provide a sitemap_url, and the sitemap URL couldn't be auto-detected.")

        Site = django_apps.get_model('sites.Site')
        current_site = Site.objects.get_current()
        scheme = 'https' if sitemap_uses_https else 'http'
        return '%s://%s%s' % (scheme, current_site.domain, sitemap_url)

    class Sitemap:
        # This limit is defined by Google. See the index documentation at
        # https://www.sitemaps.org/protocol.html#index.
        limit = 50000

        # If protocol is None, the URLs in the sitemap will use the protocol
        # with which the sitemap was requested.
        protocol = None

        def __get(self, name, obj, default=None):
            try:
                attr = getattr(self, name)
            except AttributeError:
                return default
            if callable(attr):
                return attr(obj)
            return attr

        def items(self):
            return []

        def location(self, obj):
            return obj.get_absolute_url()

        @property
        def paginator(self):
            return paginator.Paginator(self.items(), self.limit)

        def get_urls(self, page=1, site=None, protocol=None):
            # Determine protocol
            if self.protocol is not None:
                protocol = self.protocol
            if protocol is None:
                protocol = 'http'

            # Determine domain
            if site is None:
                if django_apps.is_installed('django.contrib.sites'):
                    Site = django_apps.get_model('sites.Site')
                    try:
                        site = Site.objects.get_current()
                    except Site.DoesNotExist:
                        pass
                if site is None:
                    raise ImproperlyConfigured(
                        "To use sitemaps, either enable the sites framework or pass "
                        "a Site/RequestSite object in your view."
                    )
            domain = site.domain

            if getattr(self, 'i18n', False):
                urls = []
                current_lang_code = translation.get_language()
                for lang_code, lang_name in settings.LANGUAGES:
                    translation.activate(lang_code)
                    urls += self._urls(page, protocol, domain)
                translation.activate(current_lang_code)
            else:
                urls = self._urls(page, protocol, domain)

            return urls

        def _urls(self, page, protocol, domain):
            urls = []
            latest_lastmod = None
            all_items_lastmod = True  # track if all items have a lastmod
            for item in self.paginator.page(page).object_list:
                loc = "%s://%s%s" % (protocol, domain, self.__get('location', item))
                priority = self.__get('priority', item)
                lastmod = self.__get('lastmod', item)
                if all_items_lastmod:
                    all_items_lastmod = lastmod is not None
                    if (all_items_lastmod and
                            (latest_lastmod is None or lastmod > latest_lastmod)):
                        latest_lastmod = lastmod
                url_info = {
                    'item': item,
                    'location': loc,
                    'lastmod': lastmod,
                    'changefreq': self.__get('changefreq', item),
                    'priority': str(priority if priority is not None else ''),
                }
                urls.append(url_info)
            if all_items_lastmod and latest_lastmod:
                self.latest_lastmod = latest_lastmod
            return urls

    class GenericSitemap(Sitemap):
        priority = None
        changefreq = None

        def __init__(self, info_dict, priority=None, changefreq=None, protocol=None):
            self.queryset = info_dict['queryset']
            self.date_field = info_dict.get('date_field')
            self.priority = priority
            self.changefreq = changefreq
            self.protocol = protocol

        def items(self):
            # Make sure to return a clone; we don't want premature evaluation.
            return self.queryset.filter()

        def lastmod(self, item):
            if self.date_field is not None:
                return getattr(item, self.date_field)
            return None

    default_app_config = 'django.contrib.sitemaps.apps.SiteMapsConfig'