# -*- coding: utf-8 -*-
from datetime import datetime
from django.db import models
from django.conf import settings
from django.db.models import signals
from django.contrib.sites.models import Site
from django.contrib.sites.managers import CurrentSiteManager
from django.utils.translation import gettext_lazy
from django.template import TemplateDoesNotExist
from django.template.loader import find_template_source
from django.core.exceptions import ImproperlyConfigured
class Template(models.Model):
"""
Defines a template model for use with the database template loader.
The field ``name`` is the equivalent to the filename of a static template.
"""
name = models.CharField(_('name'), unique=True, max_length=100,
help_text=_("Example: 'flatpages/default.html'"))
content = models.TextField(_('content'), blank=True)
sites = models.ManyToManyField(Site)
creation_date = models.DateTimeField(_('creation date'),
default=datetime.now)
last_changed = models.DateTimeField(_('last changed'),
default=datetime.now)
objects = models.Manager()
on_site = CurrentSiteManager('sites')
class Meta:
db_table = 'django_template'
verbose_name = _('template')
verbose_name_plural = _('templates')
ordering = ('name',)
def __unicode__(self):
return self.name
def save(self, *args, **kwargs):
self.last_changed = datetime.now()
# If content is empty look for a template with the given name and
# populate the template instance with its content.
if not self.content:
try:
source, origin = find_template_source(self.name)
if source:
self.content = source
except TemplateDoesNotExist:
pass
super(Template, self).save(*args, **kwargs)
def get_cache_backend():
path = getattr(settings, 'DBTEMPLATES_CACHE_BACKEND', False)
if path:
i = path.rfind('.')
module, attr = path[:i], path[i+1:]
try:
mod = __import__(module, {}, {}, [attr])
except ImportError, e:
raise ImproperlyConfigured, 'Error importing dbtemplates cache backend %s: "%s"' % (module, e)
try:
cls = getattr(mod, attr)
except AttributeError:
raise ImproperlyConfigured, 'Module "%s" does not define a "%s" cache backend' % (module, attr)
return cls()
return False
backend = get_cache_backend()
def add_default_site(instance, **kwargs):
"""
Called via Django's signals to cache the templates, if the template
in the database was added or changed, only if DBTEMPLATES_ADD_DEFAULT_SITE
setting is set.
"""
if getattr(settings, 'DBTEMPLATES_ADD_DEFAULT_SITE', True):
current_site = Site.objects.get_current()
if current_site not in instance.sites.all():
instance.sites.add(current_site)
signals.post_save.connect(add_default_site, sender=Template)
def add_template_to_cache(instance, **kwargs):
"""
Called via Django's signals to cache the templates, if the template
in the database was added or changed.
"""
remove_cached_template(instance)
backend.save(instance.name, instance.content)
def remove_cached_template(instance, **kwargs):
"""
Called via Django's signals to remove cached templates, if the template
in the database was changed or deleted.
"""
backend.remove(instance.name)
if backend:
signals.post_save.connect(add_template_to_cache, sender=Template)
signals.pre_delete.connect(remove_cached_template, sender=Template)
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