file_cache.py 文件源码

def set(self, url, content):
    f = LockedFile(self._file, 'r+', 'r')
    try:
      f.open_and_lock()
      if f.is_locked():
        cache = _read_or_initialize_cache(f)
        cache[url] = (content, _to_timestamp(datetime.datetime.now()))
        # Remove stale cache.
        for k, (_, timestamp) in list(cache.items()):
          if _to_timestamp(datetime.datetime.now()) >= timestamp + self._max_age:
            del cache[k]
        f.file_handle().truncate(0)
        f.file_handle().seek(0)
        json.dump(cache, f.file_handle())
      else:
        logger.debug('Could not obtain a lock for the cache file.')
    except Exception as e:
      logger.warning(e, exc_info=True)
    finally:
      f.unlock_and_close()