gistfile1.txt

from importlib.machinery import ModuleSpec
from .source import make_source

# For some reasons I need to be able to have dynamically generated modules so I can do
# 
#  from borsa_italiana.isin.<dynamic value> import Source
#

MAGIC_MODULE_NAME = 'borsa_italiana.isin'
MODULE_PATH = []  # dummy, but we need to set it to something, but why? 


class ModuleFinder:
    """
    Connects ModuleImporter to the import machinery
    """

    @classmethod
    def find_spec(cls, fullname, path=None, target=None):
        """
        If this returns a module spec, use our importer
        """
        name_parts = fullname.split('.')
        # maybe use startswith on the strings
        if name_parts[:2] != MAGIC_MODULE_NAME.split('.') or len(name_parts) > 3:
            return None
        else:
            return ModuleSpec(fullname, ModuleImporter())


class ModuleImporter:
    """
    Populates the magic isin.foo modules
    """

    @classmethod
    def create_module(cls, spec):
        """
        Returning None lets Python create a normal empty module.
        """
        return None

    @classmethod
    def exec_module(cls, module):
        """
        Fills the module with code
        """
        name_parts = module.__name__.split('.')

        # __path__ must be set or things explode
        if module.__name__ == MAGIC_MODULE_NAME:
            module.__path__ = MODULE_PATH  # ?? do I need this?
        if module.__name__.startswith(MAGIC_MODULE_NAME):
            module.Source = make_source(lambda request: name_parts[-1])
        else:
            assert False, 'Importer tried to handle a module it should not know about %s'.format(module.__name__)