Extensions
==========

.. currentmodule:: websockets.extensions

The WebSocket protocol supports extensions_.

At the time of writing, there's only one `registered extension`_ with a public
specification, WebSocket Per-Message Deflate.

.. _extensions: https://www.rfc-editor.org/rfc/rfc6455.html#section-9
.. _registered extension: https://www.iana.org/assignments/websocket/websocket.xhtml#extension-name

Per-Message Deflate
-------------------

.. automodule:: websockets.extensions.permessage_deflate

    :mod:`websockets.extensions.permessage_deflate` implements WebSocket
    Per-Message Deflate.

    This extension is specified in :rfc:`7692`.

    Refer to the :doc:`topic guide on compression <../topics/compression>` to
    learn more about tuning compression settings.

    .. autoclass:: ClientPerMessageDeflateFactory

    .. autoclass:: ServerPerMessageDeflateFactory

Base classes
------------

.. automodule:: websockets.extensions

    :mod:`websockets.extensions` defines base classes for implementing
     extensions.

    Refer to the :doc:`how-to guide on extensions <../howto/extensions>` to
    learn more about writing an extension.

    .. autoclass:: Extension

        .. autoattribute:: name

        .. automethod:: decode

        .. automethod:: encode

    .. autoclass:: ClientExtensionFactory

        .. autoattribute:: name

        .. automethod:: get_request_params

        .. automethod:: process_response_params

    .. autoclass:: ServerExtensionFactory

        .. automethod:: process_request_params