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 missing 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)))