Source code for django.template.backends.django

# Since this package contains a "django" module, this is required on Python 2.
from __future__ import absolute_import

import sys
from importlib import import_module
from pkgutil import walk_packages

from django.apps import apps
from django.conf import settings
from django.template import TemplateDoesNotExist
from django.template.context import make_context
from django.template.engine import Engine
from django.template.library import InvalidTemplateLibrary
from django.utils import six

from .base import BaseEngine

[docs]class DjangoTemplates(BaseEngine): app_dirname = 'templates' def __init__(self, params): params = params.copy() options = params.pop('OPTIONS').copy() options.setdefault('autoescape', True) options.setdefault('debug', settings.DEBUG) options.setdefault('file_charset', settings.FILE_CHARSET) libraries = options.get('libraries', {}) options['libraries'] = self.get_templatetag_libraries(libraries) super(DjangoTemplates, self).__init__(params) self.engine = Engine(self.dirs, self.app_dirs, **options) def from_string(self, template_code): return Template(self.engine.from_string(template_code), self) def get_template(self, template_name): try: return Template(self.engine.get_template(template_name), self) except TemplateDoesNotExist as exc: reraise(exc, self) def get_templatetag_libraries(self, custom_libraries): """ Return a collation of template tag libraries from installed applications and the supplied custom_libraries argument. """ libraries = get_installed_libraries() libraries.update(custom_libraries) return libraries
class Template(object): def __init__(self, template, backend): self.template = template self.backend = backend @property def origin(self): return self.template.origin def render(self, context=None, request=None): context = make_context(context, request, autoescape=self.backend.engine.autoescape) try: return self.template.render(context) except TemplateDoesNotExist as exc: reraise(exc, self.backend) def copy_exception(exc, backend=None): """ Create a new TemplateDoesNotExist. Preserve its declared attributes and template debug data but discard __traceback__, __context__, and __cause__ to make this object suitable for keeping around (in a cache, for example). """ backend = backend or exc.backend new = exc.__class__(*exc.args, tried=exc.tried, backend=backend, chain=exc.chain) if hasattr(exc, 'template_debug'): new.template_debug = exc.template_debug return new def reraise(exc, backend): """ Reraise TemplateDoesNotExist while maintaining template debug information. """ new = copy_exception(exc, backend) six.reraise(exc.__class__, new, sys.exc_info()[2]) def get_installed_libraries(): """ Return the built-in template tag libraries and those from installed applications. Libraries are stored in a dictionary where keys are the individual module names, not the full module paths. Example: django.templatetags.i18n is stored as i18n. """ libraries = {} candidates = ['django.templatetags'] candidates.extend( '%s.templatetags' % for app_config in apps.get_app_configs()) for candidate in candidates: try: pkg = import_module(candidate) except ImportError: # No templatetags package defined. This is safe to ignore. continue if hasattr(pkg, '__path__'): for name in get_package_libraries(pkg): libraries[name[len(candidate) + 1:]] = name return libraries def get_package_libraries(pkg): """ Recursively yield template tag libraries defined in submodules of a package. """ for entry in walk_packages(pkg.__path__, pkg.__name__ + '.'): try: module = import_module(entry[1]) except ImportError as e: raise InvalidTemplateLibrary( "Invalid template library specified. ImportError raised when " "trying to load '%s': %s" % (entry[1], e) ) if hasattr(module, 'register'): yield entry[1]
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