82 lines
2.7 KiB
Python
82 lines
2.7 KiB
Python
from django.core.exceptions import ImproperlyConfigured, SuspiciousFileOperation
|
|
from django.template.utils import get_app_template_dirs
|
|
from django.utils._os import safe_join
|
|
from django.utils.functional import cached_property
|
|
|
|
|
|
class BaseEngine:
|
|
|
|
# Core methods: engines have to provide their own implementation
|
|
# (except for from_string which is optional).
|
|
|
|
def __init__(self, params):
|
|
"""
|
|
Initialize the template engine.
|
|
|
|
`params` is a dict of configuration settings.
|
|
"""
|
|
params = params.copy()
|
|
self.name = params.pop("NAME")
|
|
self.dirs = list(params.pop("DIRS"))
|
|
self.app_dirs = params.pop("APP_DIRS")
|
|
if params:
|
|
raise ImproperlyConfigured(
|
|
"Unknown parameters: {}".format(", ".join(params))
|
|
)
|
|
|
|
@property
|
|
def app_dirname(self):
|
|
raise ImproperlyConfigured(
|
|
"{} doesn't support loading templates from installed "
|
|
"applications.".format(self.__class__.__name__)
|
|
)
|
|
|
|
def from_string(self, template_code):
|
|
"""
|
|
Create and return a template for the given source code.
|
|
|
|
This method is optional.
|
|
"""
|
|
raise NotImplementedError(
|
|
"subclasses of BaseEngine should provide a from_string() method"
|
|
)
|
|
|
|
def get_template(self, template_name):
|
|
"""
|
|
Load and return a template for the given name.
|
|
|
|
Raise TemplateDoesNotExist if no such template exists.
|
|
"""
|
|
raise NotImplementedError(
|
|
"subclasses of BaseEngine must provide a get_template() method"
|
|
)
|
|
|
|
# Utility methods: they are provided to minimize code duplication and
|
|
# security issues in third-party backends.
|
|
|
|
@cached_property
|
|
def template_dirs(self):
|
|
"""
|
|
Return a list of directories to search for templates.
|
|
"""
|
|
# Immutable return value because it's cached and shared by callers.
|
|
template_dirs = tuple(self.dirs)
|
|
if self.app_dirs:
|
|
template_dirs += get_app_template_dirs(self.app_dirname)
|
|
return template_dirs
|
|
|
|
def iter_template_filenames(self, template_name):
|
|
"""
|
|
Iterate over candidate files for template_name.
|
|
|
|
Ignore files that don't lie inside configured template dirs to avoid
|
|
directory traversal attacks.
|
|
"""
|
|
for template_dir in self.template_dirs:
|
|
try:
|
|
yield safe_join(template_dir, template_name)
|
|
except SuspiciousFileOperation:
|
|
# The joined path was located outside of this template_dir
|
|
# (it might be inside another one, so this isn't fatal).
|
|
pass
|