108 lines
3.7 KiB
Python
108 lines
3.7 KiB
Python
import copy
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import os
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import sys
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from importlib import import_module
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from importlib.util import find_spec as importlib_find
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def cached_import(module_path, class_name):
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# Check whether module is loaded and fully initialized.
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if not (
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(module := sys.modules.get(module_path))
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and (spec := getattr(module, "__spec__", None))
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and getattr(spec, "_initializing", False) is False
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):
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module = import_module(module_path)
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return getattr(module, class_name)
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def import_string(dotted_path):
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"""
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Import a dotted module path and return the attribute/class designated by the
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last name in the path. Raise ImportError if the import failed.
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"""
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try:
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module_path, class_name = dotted_path.rsplit(".", 1)
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except ValueError as err:
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raise ImportError("%s doesn't look like a module path" % dotted_path) from err
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try:
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return cached_import(module_path, class_name)
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except AttributeError as err:
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raise ImportError(
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'Module "%s" does not define a "%s" attribute/class'
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% (module_path, class_name)
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) from err
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def autodiscover_modules(*args, **kwargs):
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"""
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Auto-discover INSTALLED_APPS modules and fail silently when
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not present. This forces an import on them to register any admin bits they
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may want.
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You may provide a register_to keyword parameter as a way to access a
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registry. This register_to object must have a _registry instance variable
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to access it.
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"""
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from django.apps import apps
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register_to = kwargs.get("register_to")
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for app_config in apps.get_app_configs():
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for module_to_search in args:
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# Attempt to import the app's module.
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try:
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if register_to:
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before_import_registry = copy.copy(register_to._registry)
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import_module("%s.%s" % (app_config.name, module_to_search))
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except Exception:
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# Reset the registry to the state before the last import
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# as this import will have to reoccur on the next request and
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# this could raise NotRegistered and AlreadyRegistered
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# exceptions (see #8245).
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if register_to:
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register_to._registry = before_import_registry
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# Decide whether to bubble up this error. If the app just
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# doesn't have the module in question, we can ignore the error
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# attempting to import it, otherwise we want it to bubble up.
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if module_has_submodule(app_config.module, module_to_search):
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raise
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def module_has_submodule(package, module_name):
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"""See if 'module' is in 'package'."""
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try:
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package_name = package.__name__
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package_path = package.__path__
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except AttributeError:
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# package isn't a package.
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return False
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full_module_name = package_name + "." + module_name
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try:
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return importlib_find(full_module_name, package_path) is not None
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except ModuleNotFoundError:
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# When module_name is an invalid dotted path, Python raises
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# ModuleNotFoundError.
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return False
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def module_dir(module):
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"""
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Find the name of the directory that contains a module, if possible.
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Raise ValueError otherwise, e.g. for namespace packages that are split
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over several directories.
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"""
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# Convert to list because __path__ may not support indexing.
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paths = list(getattr(module, "__path__", []))
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if len(paths) == 1:
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return paths[0]
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else:
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filename = getattr(module, "__file__", None)
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if filename is not None:
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return os.path.dirname(filename)
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raise ValueError("Cannot determine directory containing %s" % module)
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