django1/django/contrib/sites/models.py

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2013-02-25 01:35:08 +08:00
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
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
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.
"""
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)