pyiqa.utils.file_client
=======================

.. py:module:: pyiqa.utils.file_client




Module Contents
---------------

.. py:class:: BaseStorageBackend

   Abstract class of storage backends.

   All backends need to implement two apis: ``get()`` and ``get_text()``.
   ``get()`` reads the file as a byte stream and ``get_text()`` reads the file
   as texts.


   .. py:method:: get(filepath)
      :abstractmethod:



   .. py:method:: get_text(filepath)
      :abstractmethod:



.. py:class:: MemcachedBackend(server_list_cfg, client_cfg, sys_path=None)

   Bases: :py:obj:`BaseStorageBackend`


   Memcached storage backend.

   .. attribute:: server_list_cfg

      Config file for memcached server list.

      :type: str

   .. attribute:: client_cfg

      Config file for memcached client.

      :type: str

   .. attribute:: sys_path

      Additional path to be appended to `sys.path`.
      Default: None.

      :type: str | None


   .. py:method:: get(filepath)


   .. py:method:: get_text(filepath)
      :abstractmethod:



.. py:class:: HardDiskBackend

   Bases: :py:obj:`BaseStorageBackend`


   Raw hard disks storage backend.


   .. py:method:: get(filepath)


   .. py:method:: get_text(filepath)


.. py:class:: LmdbBackend(db_paths, client_keys='default', readonly=True, lock=False, readahead=False, **kwargs)

   Bases: :py:obj:`BaseStorageBackend`


   Lmdb storage backend.

   :param db_paths: Lmdb database paths.
   :type db_paths: str | list[str]
   :param client_keys: Lmdb client keys. Default: 'default'.
   :type client_keys: str | list[str]
   :param readonly: Lmdb environment parameter. If True,
                    disallow any write operations. Default: True.
   :type readonly: bool, optional
   :param lock: Lmdb environment parameter. If False, when
                concurrent access occurs, do not lock the database. Default: False.
   :type lock: bool, optional
   :param readahead: Lmdb environment parameter. If False,
                     disable the OS filesystem readahead mechanism, which may improve
                     random read performance when a database is larger than RAM.
                     Default: False.
   :type readahead: bool, optional

   .. attribute:: db_paths

      Lmdb database path.

      :type: list

   .. attribute:: _client

      A list of several lmdb envs.

      :type: list


   .. py:method:: get(filepath, client_key)

      Get values according to the filepath from one lmdb named client_key.

      :param filepath (str | obj: `Path`): Here, filepath is the lmdb key.
      :param client_key: Used for distinguishing different lmdb envs.
      :type client_key: str



   .. py:method:: get_text(filepath)
      :abstractmethod:



.. py:class:: FileClient(backend='disk', **kwargs)

   Bases: :py:obj:`object`


   A general file client to access files in different backend.

   The client loads a file or text in a specified backend from its path
   and return it as a binary file. it can also register other backend
   accessor with a given name and backend class.

   .. attribute:: backend

      The storage backend type. Options are "disk",
      "memcached" and "lmdb".

      :type: str

   .. attribute:: client

      The backend object.

      :type: :obj:`BaseStorageBackend`


   .. py:method:: get(filepath, client_key='default')


   .. py:method:: get_text(filepath)