diff --git a/certifi/compat.py b/certifi/compat.py new file mode 100644 index 00000000..e037eaa7 --- /dev/null +++ b/certifi/compat.py @@ -0,0 +1,17 @@ +""" +Fallback for Python prior to 3.9 where importlib_resources +is not available. +Does not support modules where __file__ is not defined on +the module. +""" + +import os + + +def read_text(_module, _path): + with open(where(), "r", encoding="ascii") as data: + return data.read() + + +def where(): + return os.path.join(os.path.dirname(__file__), "cacert.pem") diff --git a/certifi/core.py b/certifi/core.py index 5d2b8cd3..4fb62fd3 100644 --- a/certifi/core.py +++ b/certifi/core.py @@ -6,55 +6,13 @@ This module returns the installation location of cacert.pem or its contents. """ -import os -try: - from importlib.resources import path as get_path, read_text - - _CACERT_CTX = None - _CACERT_PATH = None - - def where(): - # This is slightly terrible, but we want to delay extracting the file - # in cases where we're inside of a zipimport situation until someone - # actually calls where(), but we don't want to re-extract the file - # on every call of where(), so we'll do it once then store it in a - # global variable. - global _CACERT_CTX - global _CACERT_PATH - if _CACERT_PATH is None: - # This is slightly janky, the importlib.resources API wants you to - # manage the cleanup of this file, so it doesn't actually return a - # path, it returns a context manager that will give you the path - # when you enter it and will do any cleanup when you leave it. In - # the common case of not needing a temporary file, it will just - # return the file system location and the __exit__() is a no-op. - # - # We also have to hold onto the actual context manager, because - # it will do the cleanup whenever it gets garbage collected, so - # we will also store that at the global level as well. - _CACERT_CTX = get_path("certifi", "cacert.pem") - _CACERT_PATH = str(_CACERT_CTX.__enter__()) - - return _CACERT_PATH - -except ImportError: - # This fallback will work for Python versions prior to 3.7 that lack the - # importlib.resources module but relies on the existing `where` function - # so won't address issues with environments like PyOxidizer that don't set - # __file__ on modules. - def read_text(_module, _path, encoding="ascii"): - with open(where(), "r", encoding=encoding) as data: - return data.read() - - # If we don't have importlib.resources, then we will just do the old logic - # of assuming we're on the filesystem and munge the path directly. - def where(): - f = os.path.dirname(__file__) - - return os.path.join(f, "cacert.pem") +try: + from .resources import where, read_text +except Exception: + from .compat import where, read_text # noqa: F401 def contents(): - return read_text("certifi", "cacert.pem", encoding="ascii") + return read_text("certifi", "cacert.pem") diff --git a/certifi/resources.py b/certifi/resources.py new file mode 100644 index 00000000..3ce5450d --- /dev/null +++ b/certifi/resources.py @@ -0,0 +1,28 @@ +import atexit +import functools + +try: + from importlib import resources +except ImportError: + import importlib_resources as resources + + +# ensure 'files' API is present +resources.files +read_text = resources.read_text + + +def as_file(path): + """ + Ensure the path is a file on the file system for the duration + of the interpreter run. + """ + ctx = resources.as_file(path) + tmp_copy = ctx.__enter__() + atexit.register(tmp_copy.__exit__, None, None, None) + return tmp_copy + + +@functools.lru_cache() +def where(): + return as_file(resources.files('certifi') / 'cacert.pem')