1  import functools
       2  import warnings
       3  import re
       4  import textwrap
       5  import email.message
       6  
       7  from ._text import FoldedCase
       8  
       9  
      10  # Do not remove prior to 2024-01-01 or Python 3.14
      11  _warn = functools.partial(
      12      warnings.warn,
      13      "Implicit None on return values is deprecated and will raise KeyErrors.",
      14      DeprecationWarning,
      15      stacklevel=2,
      16  )
      17  
      18  
      19  class ESC[4;38;5;81mMessage(ESC[4;38;5;149memailESC[4;38;5;149m.ESC[4;38;5;149mmessageESC[4;38;5;149m.ESC[4;38;5;149mMessage):
      20      multiple_use_keys = set(
      21          map(
      22              FoldedCase,
      23              [
      24                  'Classifier',
      25                  'Obsoletes-Dist',
      26                  'Platform',
      27                  'Project-URL',
      28                  'Provides-Dist',
      29                  'Provides-Extra',
      30                  'Requires-Dist',
      31                  'Requires-External',
      32                  'Supported-Platform',
      33                  'Dynamic',
      34              ],
      35          )
      36      )
      37      """
      38      Keys that may be indicated multiple times per PEP 566.
      39      """
      40  
      41      def __new__(cls, orig: email.message.Message):
      42          res = super().__new__(cls)
      43          vars(res).update(vars(orig))
      44          return res
      45  
      46      def __init__(self, *args, **kwargs):
      47          self._headers = self._repair_headers()
      48  
      49      # suppress spurious error from mypy
      50      def __iter__(self):
      51          return super().__iter__()
      52  
      53      def __getitem__(self, item):
      54          """
      55          Warn users that a ``KeyError`` can be expected when a
      56          mising key is supplied. Ref python/importlib_metadata#371.
      57          """
      58          res = super().__getitem__(item)
      59          if res is None:
      60              _warn()
      61          return res
      62  
      63      def _repair_headers(self):
      64          def redent(value):
      65              "Correct for RFC822 indentation"
      66              if not value or '\n' not in value:
      67                  return value
      68              return textwrap.dedent(' ' * 8 + value)
      69  
      70          headers = [(key, redent(value)) for key, value in vars(self)['_headers']]
      71          if self._payload:
      72              headers.append(('Description', self.get_payload()))
      73          return headers
      74  
      75      @property
      76      def json(self):
      77          """
      78          Convert PackageMetadata to a JSON-compatible format
      79          per PEP 0566.
      80          """
      81  
      82          def transform(key):
      83              value = self.get_all(key) if key in self.multiple_use_keys else self[key]
      84              if key == 'Keywords':
      85                  value = re.split(r'\s+', value)
      86              tk = key.lower().replace('-', '_')
      87              return tk, value
      88  
      89          return dict(map(transform, map(FoldedCase, self)))