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import urlparse
from mod_pywebsocket.extensions import PerMessageDeflateExtensionProcessor


def _get_permessage_deflate_extension_processor(request):
    for extension_processor in request.ws_extension_processors:
        if isinstance(extension_processor, PerMessageDeflateExtensionProcessor):
            return extension_processor
    return None


def web_socket_do_extra_handshake(request):
    processor = _get_permessage_deflate_extension_processor(request)
    # Remove extension processors other than PerMessageDeflateProcessor
    # to avoid conflict.
    request.ws_extension_processors = [processor]
    if not processor:
        return
    # Insert fake server_... parameters to make the server create
    # a negotiation response including the parameters.
    processor._request.add_parameter('server_no_context_takeover', None)
    processor._request.add_parameter('server_max_window_bits', '15')


def web_socket_transfer_data(request):
    pass


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