Code source de django.contrib.sites.models

from __future__ import unicode_literals

import string

from django.db import models
from django.db.models.signals import pre_save, pre_delete
from django.utils.translation import ugettext_lazy as _
from django.utils.encoding import python_2_unicode_compatible
from django.core.exceptions import ValidationError


SITE_CACHE = {}


def _simple_domain_name_validator(value):
    """
    Validates that the given value contains no whitespaces to prevent common
    typos.
    """
    if not value:
        return
    checks = ((s in value) for s in string.whitespace)
    if any(checks):
        raise ValidationError(
            _("The domain name cannot contain any spaces or tabs."),
            code='invalid',
        )


class SiteManager(models.Manager):

    def get_current(self):
        """
        Returns the current ``Site`` based on the SITE_ID in the
        project's settings. The ``Site`` object is cached the first
        time it's retrieved from the database.
        """
        from django.conf import settings
        try:
            sid = settings.SITE_ID
        except AttributeError:
            from django.core.exceptions import ImproperlyConfigured
            raise ImproperlyConfigured("You're using the Django \"sites framework\" without having set the SITE_ID setting. Create a site in your database and set the SITE_ID setting to fix this error.")
        try:
            current_site = SITE_CACHE[sid]
        except KeyError:
            current_site = self.get(pk=sid)
            SITE_CACHE[sid] = current_site
        return current_site

    def clear_cache(self):
        """Clears the ``Site`` object cache."""
        global SITE_CACHE
        SITE_CACHE = {}


@python_2_unicode_compatible
[docs]class Site(models.Model): domain = models.CharField(_('domain name'), max_length=100, validators=[_simple_domain_name_validator]) name = models.CharField(_('display name'), max_length=50) objects = SiteManager() class Meta: db_table = 'django_site' verbose_name = _('site') verbose_name_plural = _('sites') ordering = ('domain',) def __str__(self): return self.domain
@python_2_unicode_compatible
[docs]class RequestSite(object): """ A class that shares the primary interface of Site (i.e., it has ``domain`` and ``name`` attributes) but gets its data from a Django HttpRequest object rather than from a database. The save() and delete() methods raise NotImplementedError. """
[docs] def __init__(self, request): self.domain = self.name = request.get_host()
def __str__(self): return self.domain def save(self, force_insert=False, force_update=False): raise NotImplementedError('RequestSite cannot be saved.') def delete(self): raise NotImplementedError('RequestSite cannot be deleted.')
def get_current_site(request): """ Checks if contrib.sites is installed and returns either the current ``Site`` object or a ``RequestSite`` object based on the request. """ if Site._meta.installed: current_site = Site.objects.get_current() else: current_site = RequestSite(request) return current_site def clear_site_cache(sender, **kwargs): """ Clears the cache (if primed) each time a site is saved or deleted """ instance = kwargs['instance'] try: del SITE_CACHE[instance.pk] except KeyError: pass pre_save.connect(clear_site_cache, sender=Site) pre_delete.connect(clear_site_cache, sender=Site)