def read_pkg_file(self, file):
        """Reads the metadata values from a file object."""
        msg = message_from_file(file)

        def _read_field(name):
            value = msg[name]
            if value and value != "UNKNOWN":
                return value

        def _read_list(name):
            values = msg.get_all(name, None)
            if values == []:
                return None
            return values

        metadata_version = msg['metadata-version']
        self.name = _read_field('name')
        self.version = _read_field('version')
        self.description = _read_field('summary')
        # we are filling author only.
        self.author = _read_field('author')
        self.maintainer = None
        self.author_email = _read_field('author-email')
        self.maintainer_email = None
        self.url = _read_field('home-page')
        self.license = _read_field('license')

        if 'download-url' in msg:
            self.download_url = _read_field('download-url')
        else:
            self.download_url = None

        self.long_description = _read_field('description')
        self.description = _read_field('summary')

        if 'keywords' in msg:
            self.keywords = _read_field('keywords').split(',')

        self.platforms = _read_list('platform')
        self.classifiers = _read_list('classifier')

        # PEP 314 - these fields only exist in 1.1
        if metadata_version == '1.1':
            self.requires = _read_list('requires')
            self.provides = _read_list('provides')
            self.obsoletes = _read_list('obsoletes')
        else:
            self.requires = None
            self.provides = None
            self.obsoletes = None
Reads the metadata values from a file object.
product/gradle-plugin/src/main/python/setuptools/_distutils/dist.py