accident-map-blog-3.py

class CachableDataSource:

    def __init__(self, url):
        self.url = url
        self.cache_filepath = self.__get_cache_filepath(url)
        if os.path.isfile(self.cache_filepath):
            self.__load_cache()
        else:
            self.__load_dataframe()
            self.__save_cache()

    def __load_cache(self):
        self.dataframe = pd.read_pickle(self.cache_filepath)

    def __save_cache(self):
        self.dataframe.to_pickle(self.cache_filepath)

    def __load_dataframe(self):
        self.dataframe = pd.read_csv(self.url)

    @classmethod
    def __get_cache_filepath(cls, url):
        return CACHE_PREFIX + hashlib.md5(url.encode("utf-8")).hexdigest()