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cpython/Lib/importlib/metadata/_adapters.py
2023-04-20 22:12:48 -04:00

90 lines
2.3 KiB
Python

import functools
import warnings
import re
import textwrap
import email.message
from ._text import FoldedCase
# Do not remove prior to 2024-01-01 or Python 3.14
_warn = functools.partial(
warnings.warn,
"Implicit None on return values is deprecated and will raise KeyErrors.",
DeprecationWarning,
stacklevel=2,
)
class Message(email.message.Message):
multiple_use_keys = set(
map(
FoldedCase,
[
'Classifier',
'Obsoletes-Dist',
'Platform',
'Project-URL',
'Provides-Dist',
'Provides-Extra',
'Requires-Dist',
'Requires-External',
'Supported-Platform',
'Dynamic',
],
)
)
"""
Keys that may be indicated multiple times per PEP 566.
"""
def __new__(cls, orig: email.message.Message):
res = super().__new__(cls)
vars(res).update(vars(orig))
return res
def __init__(self, *args, **kwargs):
self._headers = self._repair_headers()
# suppress spurious error from mypy
def __iter__(self):
return super().__iter__()
def __getitem__(self, item):
"""
Warn users that a ``KeyError`` can be expected when a
mising key is supplied. Ref python/importlib_metadata#371.
"""
res = super().__getitem__(item)
if res is None:
_warn()
return res
def _repair_headers(self):
def redent(value):
"Correct for RFC822 indentation"
if not value or '\n' not in value:
return value
return textwrap.dedent(' ' * 8 + value)
headers = [(key, redent(value)) for key, value in vars(self)['_headers']]
if self._payload:
headers.append(('Description', self.get_payload()))
return headers
@property
def json(self):
"""
Convert PackageMetadata to a JSON-compatible format
per PEP 0566.
"""
def transform(key):
value = self.get_all(key) if key in self.multiple_use_keys else self[key]
if key == 'Keywords':
value = re.split(r'\s+', value)
tk = key.lower().replace('-', '_')
return tk, value
return dict(map(transform, map(FoldedCase, self)))