[Python-Dev] accept the wheel PEPs 425, 426, 427 (original) (raw)

Daniel Holth dholth at gmail.com
Sun Oct 21 04:56:49 CEST 2012

I'm really happy with moving the troublesome Description: field to the payload. Email Policy() is useful too.

http://hg.python.org/peps/rev/74868fe8ba17

Metadata 1.3 is a ...

+format with no maximum line length, followed by a blank line and an +arbitrary payload. It is parseable by the email module with an +appropriate email.policy.Policy().

description is deprecated...

+Since Metadata 1.3 the recommended place for the description is in the +payload section of the document, after the last header. The description +needs no special formatting when included in the payload.

includes a handy...

Metadata 1.3 demo

from email.generator import Generator from email import header from email.parser import Parser from email.policy import Compat32 from email.utils import _has_surrogates

class MetadataPolicy(Compat32): max_line_length = 0 continuation_whitespace = '\t'

def _sanitize_header(self, name, value):
    if not isinstance(value, str):
        return value
    if _has_surrogates(value):
        raise NotImplementedError()
    else:
        return value

def _fold(self, name, value, sanitize):
    body = ((self.linesep+self.continuation_whitespace)
            .join(value.splitlines()))
    return ''.join((name, ': ', body, self.linesep))

if name == "main": import sys import textwrap

pkg_info = """\

Metadata-Version: 1.3 Name: package Version: 0.1.0 Summary: A package. Description: Description ===========

A description of the package.

"""

m = Parser(policy=MetadataPolicy()).parsestr(pkg_info)

m['License'] = 'GPL'
description = m['Description']
description_lines = description.splitlines()
m.set_payload(description_lines[0]
        + '\n'
        + textwrap.dedent('\n'.join(description_lines[1:]))
        + '\n')
del m['Description']

# Correct if sys.stdout.encoding == 'UTF-8':
Generator(sys.stdout, maxheaderlen=0).flatten(m)

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