mirror of
https://gitlab.winehq.org/wine/wine-gecko.git
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251 lines
8.9 KiB
Python
Executable File
251 lines
8.9 KiB
Python
Executable File
# Copyright 2011, Google Inc.
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# All rights reserved.
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#
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions are
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# met:
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#
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# * Redistributions of source code must retain the above copyright
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# notice, this list of conditions and the following disclaimer.
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# * Redistributions in binary form must reproduce the above
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# copyright notice, this list of conditions and the following disclaimer
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# in the documentation and/or other materials provided with the
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# distribution.
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# * Neither the name of Google Inc. nor the names of its
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# contributors may be used to endorse or promote products derived from
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# this software without specific prior written permission.
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#
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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"""WebSocket HyBi 07 opening handshake processor."""
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# Note: request.connection.write is used in this module, even though mod_python
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# document says that it should be used only in connection handlers.
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# Unfortunately, we have no other options. For example, request.write is not
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# suitable because it doesn't allow direct raw bytes writing.
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import base64
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import logging
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import os
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import re
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from mod_pywebsocket import common
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from mod_pywebsocket.stream import Stream
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from mod_pywebsocket.stream import StreamOptions
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from mod_pywebsocket import util
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from mod_pywebsocket.handshake._base import HandshakeError
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from mod_pywebsocket.handshake._base import check_header_lines
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from mod_pywebsocket.handshake._base import get_mandatory_header
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_MANDATORY_HEADERS = [
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# key, expected value or None
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[common.UPGRADE_HEADER, common.WEBSOCKET_UPGRADE_TYPE],
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[common.CONNECTION_HEADER, common.UPGRADE_CONNECTION_TYPE],
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]
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_BASE64_REGEX = re.compile('^[+/0-9A-Za-z]*=*$')
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def compute_accept(key):
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"""Computes value for the Sec-WebSocket-Accept header from value of the
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Sec-WebSocket-Key header.
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"""
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accept_binary = util.sha1_hash(
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key + common.WEBSOCKET_ACCEPT_UUID).digest()
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accept = base64.b64encode(accept_binary)
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return (accept, accept_binary)
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class Handshaker(object):
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"""This class performs WebSocket handshake."""
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def __init__(self, request, dispatcher):
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"""Construct an instance.
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Args:
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request: mod_python request.
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dispatcher: Dispatcher (dispatch.Dispatcher).
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Handshaker will add attributes such as ws_resource during handshake.
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"""
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self._logger = util.get_class_logger(self)
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self._request = request
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self._dispatcher = dispatcher
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def do_handshake(self):
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check_header_lines(self._request, _MANDATORY_HEADERS)
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self._request.ws_resource = self._request.uri
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unused_host = get_mandatory_header(self._request, common.HOST_HEADER)
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self._get_origin()
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self._check_version()
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self._set_protocol()
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self._set_extensions()
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key = self._get_key()
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(accept, accept_binary) = compute_accept(key)
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self._logger.debug('Sec-WebSocket-Accept: %r (%s)' %
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(accept, util.hexify(accept_binary)))
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self._logger.debug('IETF HyBi 07 protocol')
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self._request.ws_version = common.VERSION_HYBI07
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stream_options = StreamOptions()
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stream_options.deflate = self._request.ws_deflate
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self._request.ws_stream = Stream(self._request, stream_options)
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self._request.ws_close_code = None
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self._request.ws_close_reason = None
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self._dispatcher.do_extra_handshake(self._request)
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if self._request.ws_requested_protocols is not None:
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if self._request.ws_protocol is None:
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raise HandshakeError(
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'do_extra_handshake must choose one subprotocol from '
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'ws_requested_protocols and set it to ws_protocol')
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# TODO(tyoshino): Validate selected subprotocol value.
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self._logger.debug(
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'Subprotocol accepted: %r',
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self._request.ws_protocol)
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else:
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if self._request.ws_protocol is not None:
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raise HandshakeError(
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'ws_protocol must be None when the client didn\'t request '
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'any subprotocol')
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self._send_handshake(accept)
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def _get_origin(self):
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origin = self._request.headers_in.get(
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common.SEC_WEBSOCKET_ORIGIN_HEADER)
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self._request.ws_origin = origin
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def _check_version(self):
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unused_value = get_mandatory_header(
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self._request, common.SEC_WEBSOCKET_VERSION_HEADER, '7')
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def _set_protocol(self):
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self._request.ws_protocol = None
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protocol_header = self._request.headers_in.get(
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common.SEC_WEBSOCKET_PROTOCOL_HEADER)
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if not protocol_header:
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self._request.ws_requested_protocols = None
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return
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# TODO(tyoshino): Validate the header value.
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requested_protocols = protocol_header.split(',')
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self._request.ws_requested_protocols = [
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s.strip() for s in requested_protocols]
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self._logger.debug('Subprotocols requested: %r', requested_protocols)
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def _set_extensions(self):
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self._request.ws_deflate = False
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extensions_header = self._request.headers_in.get(
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common.SEC_WEBSOCKET_EXTENSIONS_HEADER)
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if not extensions_header:
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self._request.ws_extensions = None
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return
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self._request.ws_extensions = []
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requested_extensions = extensions_header.split(',')
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# TODO(tyoshino): Follow the ABNF in the spec.
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requested_extensions = [s.strip() for s in requested_extensions]
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for extension in requested_extensions:
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# We now support only deflate-stream extension. Any other
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# extension requests are just ignored for now.
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if extension == 'deflate-stream':
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self._request.ws_extensions.append(extension)
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self._request.ws_deflate = True
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self._logger.debug('Extensions requested: %r', requested_extensions)
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self._logger.debug(
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'Extensions accepted: %r', self._request.ws_extensions)
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def _validate_key(self, key):
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# Validate
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key_is_valid = False
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try:
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# Validate key by quick regex match before parsing by base64
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# module. Because base64 module skips invalid characters, we have
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# to do this in advance to make this server strictly reject illegal
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# keys.
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if _BASE64_REGEX.match(key):
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decoded_key = base64.b64decode(key)
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if len(decoded_key) == 16:
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key_is_valid = True
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except TypeError, e:
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pass
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if not key_is_valid:
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raise HandshakeError(
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'Illegal value for header %s: %r' %
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(common.SEC_WEBSOCKET_KEY_HEADER, key))
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return decoded_key
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def _get_key(self):
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key = get_mandatory_header(
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self._request, common.SEC_WEBSOCKET_KEY_HEADER)
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decoded_key = self._validate_key(key)
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self._logger.debug('Sec-WebSocket-Key: %r (%s)' %
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(key, util.hexify(decoded_key)))
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return key
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def _sendall(self, data):
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self._request.connection.write(data)
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def _send_header(self, name, value):
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self._sendall('%s: %s\r\n' % (name, value))
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def _send_handshake(self, accept):
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self._sendall('HTTP/1.1 101 Switching Protocols\r\n')
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self._send_header(common.UPGRADE_HEADER, common.WEBSOCKET_UPGRADE_TYPE)
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self._send_header(
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common.CONNECTION_HEADER, common.UPGRADE_CONNECTION_TYPE)
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self._send_header(common.SEC_WEBSOCKET_ACCEPT_HEADER, accept)
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# TODO(tyoshino): Encode value of protocol and extensions if any
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# special character that we have to encode by some manner.
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if self._request.ws_protocol is not None:
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self._send_header(
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common.SEC_WEBSOCKET_PROTOCOL_HEADER,
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self._request.ws_protocol)
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if self._request.ws_extensions is not None:
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self._send_header(
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common.SEC_WEBSOCKET_EXTENSIONS_HEADER,
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', '.join(self._request.ws_extensions))
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self._sendall('\r\n')
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# vi:sts=4 sw=4 et
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