"""
Wrapper class that takes a list of template loaders as an argument and attempts
to load templates from them in order, caching the result.
"""
from django.template import TemplateDoesNotExist
from django.template.loader import BaseLoader,get_template_from_string,find_template_loader,make_origin
from django.utils.importlib import import_module
from django.core.exceptions import ImproperlyConfigured
class Loader(BaseLoader):
is_usable = True
def __init__(self, loaders):
self.template_cache = {}
self._loaders = loaders
self._cached_loaders = []
@property
def loaders(self):
# Resolve loaders on demand to avoid circular imports
if not self._cached_loaders:
for loader in self._loaders:
self._cached_loaders.append(find_template_loader(loader))
return self._cached_loaders
def find_template(self, name, dirs=None):
for loader in self.loaders:
try:
template, display_name = loader(name, dirs)
return (template, make_origin(display_name, loader, name, dirs))
except TemplateDoesNotExist:
pass
raise TemplateDoesNotExist(name)
def load_template(self, template_name, template_dirs=None):
if template_name not in self.template_cache:
template, origin = self.find_template(template_name, template_dirs)
if not hasattr(template, 'render'):
try:
template = get_template_from_string(template, origin, template_name)
except TemplateDoesNotExist:
# If compiling the template we found raises TemplateDoesNotExist,
# back off to returning the source and display name for the template
# we were asked to load. This allows for correct identification (later)
# of the actual template that does not exist.
return template, origin
self.template_cache[template_name] = template
return self.template_cache[template_name], None
def reset(self):
"Empty the template cache."
self.template_cache.clear()
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