Python pkg_resources 模块，to_filename() 实例源码

def pre_run(self):
        self.egg_name = pkg_resources.safe_name(self.distribution.get_name())
        self.egg_info = "%s.egg-info" % pkg_resources.to_filename(
            self.egg_name)
        if (not os.path.exists(self.egg_info) or
                _newer_requires_files(self.egg_info)):
            ei_cmd = self.get_finalized_command('egg_info')
            ei_cmd.run()
            self.install_test_requirements()
            _copy_test_requires_to(self.egg_info)

def _get_egg_info(metadata_config, packages_root):
        egg_name = metadata_config['name']
        egg_base = packages_root

        egg_info = to_filename(egg_name) + '.egg-info'
        if egg_base != os.curdir:
            egg_info = os.path.join(egg_base, egg_info)

        return egg_info

def read(self):
        import sys
        import glob
        import warnings

        opj = os.path.join
        if self.package is not None:
            package = self.package.__package__
            if package is None:
                package = self.package.__name__

            project = pkg_resources.to_filename(pkg_resources.safe_name(self.entry_point.dist.project_name))

            package_pattern = '%s*.egg-info' % package
            project_pattern = '%s*.egg-info' % project

            file = getattr(self.package, '__file__', None)
            if file is not None:
                candidates = []

                def _add_candidate(where):
                    candidates.extend(glob.glob(where))

                for entry in sys.path:
                    if file.startswith(entry):
                        _add_candidate(opj(entry, 'EGG-INFO')) # egg?
                        for pattern in (package_pattern, project_pattern): # dist-installed?
                            _add_candidate(opj(entry, pattern))

                dir, name = os.path.split(self.package.__file__)
                for pattern in (package_pattern, project_pattern):
                    _add_candidate(opj(dir, pattern))
                    _add_candidate(opj(dir, '..', pattern))

                for candidate in candidates:
                    if os.path.isdir(candidate):
                        path = opj(candidate, 'PKG-INFO')
                    else:
                        path = candidate
                    if os.path.exists(path):
                        with open(path) as f:
                            return f.read()
        warnings.warn('No PKG-INFO found for package: %s' % self.package_name)