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# Copyright 2012, Google Inc.
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above
# copyright notice, this list of conditions and the following disclaimer
# in the documentation and/or other materials provided with the
# distribution.
# * Neither the name of Google Inc. nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
"""This file must not depend on any module specific to the WebSocket protocol.
"""
from __future__ import absolute_import
from pywebsocket3 import http_header_util
# Additional log level definitions.
LOGLEVEL_FINE = 9
# Constants indicating WebSocket protocol version.
VERSION_HYBI13 = 13
VERSION_HYBI14 = 13
VERSION_HYBI15 = 13
VERSION_HYBI16 = 13
VERSION_HYBI17 = 13
# Constants indicating WebSocket protocol latest version.
VERSION_HYBI_LATEST = VERSION_HYBI13
# Port numbers
DEFAULT_WEB_SOCKET_PORT = 80
DEFAULT_WEB_SOCKET_SECURE_PORT = 443
# Schemes
WEB_SOCKET_SCHEME = 'ws'
WEB_SOCKET_SECURE_SCHEME = 'wss'
# Frame opcodes defined in the spec.
OPCODE_CONTINUATION = 0x0
OPCODE_TEXT = 0x1
OPCODE_BINARY = 0x2
OPCODE_CLOSE = 0x8
OPCODE_PING = 0x9
OPCODE_PONG = 0xa
# UUID for the opening handshake and frame masking.
WEBSOCKET_ACCEPT_UUID = b'258EAFA5-E914-47DA-95CA-C5AB0DC85B11'
# Opening handshake header names and expected values.
UPGRADE_HEADER = 'Upgrade'
WEBSOCKET_UPGRADE_TYPE = 'websocket'
CONNECTION_HEADER = 'Connection'
UPGRADE_CONNECTION_TYPE = 'Upgrade'
HOST_HEADER = 'Host'
ORIGIN_HEADER = 'Origin'
SEC_WEBSOCKET_KEY_HEADER = 'Sec-WebSocket-Key'
SEC_WEBSOCKET_ACCEPT_HEADER = 'Sec-WebSocket-Accept'
SEC_WEBSOCKET_VERSION_HEADER = 'Sec-WebSocket-Version'
SEC_WEBSOCKET_PROTOCOL_HEADER = 'Sec-WebSocket-Protocol'
SEC_WEBSOCKET_EXTENSIONS_HEADER = 'Sec-WebSocket-Extensions'
# Extensions
PERMESSAGE_DEFLATE_EXTENSION = 'permessage-deflate'
# Status codes
# Code STATUS_NO_STATUS_RECEIVED, STATUS_ABNORMAL_CLOSURE, and
# STATUS_TLS_HANDSHAKE are pseudo codes to indicate specific error cases.
# Could not be used for codes in actual closing frames.
# Application level errors must use codes in the range
# STATUS_USER_REGISTERED_BASE to STATUS_USER_PRIVATE_MAX. The codes in the
# range STATUS_USER_REGISTERED_BASE to STATUS_USER_REGISTERED_MAX are managed
# by IANA. Usually application must define user protocol level errors in the
# range STATUS_USER_PRIVATE_BASE to STATUS_USER_PRIVATE_MAX.
STATUS_NORMAL_CLOSURE = 1000
STATUS_GOING_AWAY = 1001
STATUS_PROTOCOL_ERROR = 1002
STATUS_UNSUPPORTED_DATA = 1003
STATUS_NO_STATUS_RECEIVED = 1005
STATUS_ABNORMAL_CLOSURE = 1006
STATUS_INVALID_FRAME_PAYLOAD_DATA = 1007
STATUS_POLICY_VIOLATION = 1008
STATUS_MESSAGE_TOO_BIG = 1009
STATUS_MANDATORY_EXTENSION = 1010
STATUS_INTERNAL_ENDPOINT_ERROR = 1011
STATUS_TLS_HANDSHAKE = 1015
STATUS_USER_REGISTERED_BASE = 3000
STATUS_USER_REGISTERED_MAX = 3999
STATUS_USER_PRIVATE_BASE = 4000
STATUS_USER_PRIVATE_MAX = 4999
# Following definitions are aliases to keep compatibility. Applications must
# not use these obsoleted definitions anymore.
STATUS_NORMAL = STATUS_NORMAL_CLOSURE
STATUS_UNSUPPORTED = STATUS_UNSUPPORTED_DATA
STATUS_CODE_NOT_AVAILABLE = STATUS_NO_STATUS_RECEIVED
STATUS_ABNORMAL_CLOSE = STATUS_ABNORMAL_CLOSURE
STATUS_INVALID_FRAME_PAYLOAD = STATUS_INVALID_FRAME_PAYLOAD_DATA
STATUS_MANDATORY_EXT = STATUS_MANDATORY_EXTENSION
# HTTP status codes
HTTP_STATUS_BAD_REQUEST = 400
HTTP_STATUS_FORBIDDEN = 403
HTTP_STATUS_NOT_FOUND = 404
def is_control_opcode(opcode):
return (opcode >> 3) == 1
class ExtensionParameter(object):
"""This is exchanged on extension negotiation in opening handshake."""
def __init__(self, name):
self._name = name
# TODO(tyoshino): Change the data structure to more efficient one such
# as dict when the spec changes to say like
# - Parameter names must be unique
# - The order of parameters is not significant
self._parameters = []
def name(self):
"""Return the extension name."""
return self._name
def add_parameter(self, name, value):
"""Add a parameter."""
self._parameters.append((name, value))
def get_parameters(self):
"""Return the parameters."""
return self._parameters
def get_parameter_names(self):
"""Return the names of the parameters."""
return [name for name, unused_value in self._parameters]
def has_parameter(self, name):
"""Test if a parameter exists."""
for param_name, param_value in self._parameters:
if param_name == name:
return True
return False
def get_parameter_value(self, name):
"""Get the value of a specific parameter."""
for param_name, param_value in self._parameters:
if param_name == name:
return param_value
class ExtensionParsingException(Exception):
"""Exception to handle errors in extension parsing."""
def __init__(self, name):
super(ExtensionParsingException, self).__init__(name)
def _parse_extension_param(state, definition):
param_name = http_header_util.consume_token(state)
if param_name is None:
raise ExtensionParsingException('No valid parameter name found')
http_header_util.consume_lwses(state)
if not http_header_util.consume_string(state, '='):
definition.add_parameter(param_name, None)
return
http_header_util.consume_lwses(state)
# TODO(tyoshino): Add code to validate that parsed param_value is token
param_value = http_header_util.consume_token_or_quoted_string(state)
if param_value is None:
raise ExtensionParsingException(
'No valid parameter value found on the right-hand side of '
'parameter %r' % param_name)
definition.add_parameter(param_name, param_value)
def _parse_extension(state):
extension_token = http_header_util.consume_token(state)
if extension_token is None:
return None
extension = ExtensionParameter(extension_token)
while True:
http_header_util.consume_lwses(state)
if not http_header_util.consume_string(state, ';'):
break
http_header_util.consume_lwses(state)
try:
_parse_extension_param(state, extension)
except ExtensionParsingException as e:
raise ExtensionParsingException(
'Failed to parse parameter for %r (%r)' % (extension_token, e))
return extension
def parse_extensions(data):
"""Parse Sec-WebSocket-Extensions header value.
Returns a list of ExtensionParameter objects.
Leading LWSes must be trimmed.
"""
state = http_header_util.ParsingState(data)
extension_list = []
while True:
extension = _parse_extension(state)
if extension is not None:
extension_list.append(extension)
http_header_util.consume_lwses(state)
if http_header_util.peek(state) is None:
break
if not http_header_util.consume_string(state, ','):
raise ExtensionParsingException(
'Failed to parse Sec-WebSocket-Extensions header: '
'Expected a comma but found %r' % http_header_util.peek(state))
http_header_util.consume_lwses(state)
if len(extension_list) == 0:
raise ExtensionParsingException('No valid extension entry found')
return extension_list
def format_extension(extension):
"""Format an ExtensionParameter object."""
formatted_params = [extension.name()]
for param_name, param_value in extension.get_parameters():
if param_value is None:
formatted_params.append(param_name)
else:
quoted_value = http_header_util.quote_if_necessary(param_value)
formatted_params.append('%s=%s' % (param_name, quoted_value))
return '; '.join(formatted_params)
def format_extensions(extension_list):
"""Format a list of ExtensionParameter objects."""
formatted_extension_list = []
for extension in extension_list:
formatted_extension_list.append(format_extension(extension))
return ', '.join(formatted_extension_list)
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