#!/usr/bin/env python
#
# Copyright 2011, 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
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# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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# 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.


"""Simple WebSocket client named echo_client just because of historical reason.

mod_pywebsocket directory must be in PYTHONPATH.

Example Usage:

# server setup
 % cd $pywebsocket
 % PYTHONPATH=$cwd/src python ./mod_pywebsocket/standalone.py -p 8880 \
    -d $cwd/src/example

# run client
 % PYTHONPATH=$cwd/src python ./src/example/echo_client.py -p 8880 \
     -s localhost \
     -o http://localhost -r /echo -m test

or

# run echo client to test IETF HyBi 00 protocol
 run with --protocol-version=hybi00
"""


import base64
import codecs
import logging
from optparse import OptionParser
import os
import random
import re
import socket
import struct
import sys

from mod_pywebsocket import common
from mod_pywebsocket.extensions import DeflateFrameExtensionProcessor
from mod_pywebsocket.extensions import PerMessageDeflateExtensionProcessor
from mod_pywebsocket.extensions import _PerMessageDeflateFramer
from mod_pywebsocket.extensions import _parse_window_bits
from mod_pywebsocket.stream import Stream
from mod_pywebsocket.stream import StreamHixie75
from mod_pywebsocket.stream import StreamOptions
from mod_pywebsocket import util


_TIMEOUT_SEC = 10
_UNDEFINED_PORT = -1

_UPGRADE_HEADER = 'Upgrade: websocket\r\n'
_UPGRADE_HEADER_HIXIE75 = 'Upgrade: WebSocket\r\n'
_CONNECTION_HEADER = 'Connection: Upgrade\r\n'

# Special message that tells the echo server to start closing handshake
_GOODBYE_MESSAGE = 'Goodbye'

_PROTOCOL_VERSION_HYBI13 = 'hybi13'
_PROTOCOL_VERSION_HYBI08 = 'hybi08'
_PROTOCOL_VERSION_HYBI00 = 'hybi00'
_PROTOCOL_VERSION_HIXIE75 = 'hixie75'

# Constants for the --tls_module flag.
_TLS_BY_STANDARD_MODULE = 'ssl'
_TLS_BY_PYOPENSSL = 'pyopenssl'

# Values used by the --tls-version flag.
_TLS_VERSION_SSL23 = 'ssl23'
_TLS_VERSION_SSL3 = 'ssl3'
_TLS_VERSION_TLS1 = 'tls1'


class ClientHandshakeError(Exception):
    pass


def _build_method_line(resource):
    return 'GET %s HTTP/1.1\r\n' % resource


def _origin_header(header, origin):
    # 4.1 13. concatenation of the string "Origin:", a U+0020 SPACE character,
    # and the /origin/ value, converted to ASCII lowercase, to /fields/.
    return '%s: %s\r\n' % (header, origin.lower())


def _format_host_header(host, port, secure):
    # 4.1 9. Let /hostport/ be an empty string.
    # 4.1 10. Append the /host/ value, converted to ASCII lowercase, to
    # /hostport/
    hostport = host.lower()
    # 4.1 11. If /secure/ is false, and /port/ is not 80, or if /secure/
    # is true, and /port/ is not 443, then append a U+003A COLON character
    # (:) followed by the value of /port/, expressed as a base-ten integer,
    # to /hostport/
    if ((not secure and port != common.DEFAULT_WEB_SOCKET_PORT) or
        (secure and port != common.DEFAULT_WEB_SOCKET_SECURE_PORT)):
        hostport += ':' + str(port)
    # 4.1 12. concatenation of the string "Host:", a U+0020 SPACE
    # character, and /hostport/, to /fields/.
    return '%s: %s\r\n' % (common.HOST_HEADER, hostport)


def _receive_bytes(socket, length):
    bytes = []
    remaining = length
    while remaining > 0:
        received_bytes = socket.recv(remaining)
        if not received_bytes:
            raise IOError(
                'Connection closed before receiving requested length '
                '(requested %d bytes but received only %d bytes)' %
                (length, length - remaining))
        bytes.append(received_bytes)
        remaining -= len(received_bytes)
    return ''.join(bytes)


def _get_mandatory_header(fields, name):
    """Gets the value of the header specified by name from fields.

    This function expects that there's only one header with the specified name
    in fields. Otherwise, raises an ClientHandshakeError.
    """

    values = fields.get(name.lower())
    if values is None or len(values) == 0:
        raise ClientHandshakeError(
            '%s header not found: %r' % (name, values))
    if len(values) > 1:
        raise ClientHandshakeError(
            'Multiple %s headers found: %r' % (name, values))
    return values[0]


def _validate_mandatory_header(fields, name,
                               expected_value, case_sensitive=False):
    """Gets and validates the value of the header specified by name from
    fields.

    If expected_value is specified, compares expected value and actual value
    and raises an ClientHandshakeError on failure. You can specify case
    sensitiveness in this comparison by case_sensitive parameter. This function
    expects that there's only one header with the specified name in fields.
    Otherwise, raises an ClientHandshakeError.
    """

    value = _get_mandatory_header(fields, name)

    if ((case_sensitive and value != expected_value) or
        (not case_sensitive and value.lower() != expected_value.lower())):
        raise ClientHandshakeError(
            'Illegal value for header %s: %r (expected) vs %r (actual)' %
            (name, expected_value, value))


class _TLSSocket(object):
    """Wrapper for a TLS connection."""

    def __init__(self,
                 raw_socket, tls_module, tls_version, disable_tls_compression):
        self._logger = util.get_class_logger(self)

        if tls_module == _TLS_BY_STANDARD_MODULE:
            if tls_version == _TLS_VERSION_SSL23:
                version = ssl.PROTOCOL_SSLv23
            elif tls_version == _TLS_VERSION_SSL3:
                version = ssl.PROTOCOL_SSLv3
            elif tls_version == _TLS_VERSION_TLS1:
                version = ssl.PROTOCOL_TLSv1
            else:
                raise ValueError(
                    'Invalid --tls-version flag: %r' % tls_version)

            if disable_tls_compression:
                raise ValueError(
                    '--disable-tls-compression is not available for ssl '
                    'module')

            self._tls_socket = ssl.wrap_socket(raw_socket, ssl_version=version)

            # Print cipher in use. Handshake is done on wrap_socket call.
            self._logger.info("Cipher: %s", self._tls_socket.cipher())
        elif tls_module == _TLS_BY_PYOPENSSL:
            if tls_version == _TLS_VERSION_SSL23:
                version = OpenSSL.SSL.SSLv23_METHOD
            elif tls_version == _TLS_VERSION_SSL3:
                version = OpenSSL.SSL.SSLv3_METHOD
            elif tls_version == _TLS_VERSION_TLS1:
                version = OpenSSL.SSL.TLSv1_METHOD
            else:
                raise ValueError(
                    'Invalid --tls-version flag: %r' % tls_version)

            context = OpenSSL.SSL.Context(version)

            if disable_tls_compression:
                # OP_NO_COMPRESSION is not defined in OpenSSL module.
                context.set_options(0x00020000)

            self._tls_socket = OpenSSL.SSL.Connection(context, raw_socket)
            # Client mode.
            self._tls_socket.set_connect_state()
            self._tls_socket.setblocking(True)

            # Do handshake now (not necessary).
            self._tls_socket.do_handshake()
        else:
            raise ValueError('No TLS support module is available')

    def send(self, data):
        return self._tls_socket.write(data)

    def sendall(self, data):
        return self._tls_socket.sendall(data)

    def recv(self, size=-1):
        return self._tls_socket.read(size)

    def close(self):
        return self._tls_socket.close()

    def getpeername(self):
        return self._tls_socket.getpeername()


class ClientHandshakeBase(object):
    """A base class for WebSocket opening handshake processors for each
    protocol version.
    """

    def __init__(self):
        self._logger = util.get_class_logger(self)

    def _read_fields(self):
        # 4.1 32. let /fields/ be a list of name-value pairs, initially empty.
        fields = {}
        while True:  # "Field"
            # 4.1 33. let /name/ and /value/ be empty byte arrays
            name = ''
            value = ''
            # 4.1 34. read /name/
            name = self._read_name()
            if name is None:
                break
            # 4.1 35. read spaces
            # TODO(tyoshino): Skip only one space as described in the spec.
            ch = self._skip_spaces()
            # 4.1 36. read /value/
            value = self._read_value(ch)
            # 4.1 37. read a byte from the server
            ch = _receive_bytes(self._socket, 1)
            if ch != '\n':  # 0x0A
                raise ClientHandshakeError(
                    'Expected LF but found %r while reading value %r for '
                    'header %r' % (ch, value, name))
            self._logger.debug('Received %r header', name)
            # 4.1 38. append an entry to the /fields/ list that has the name
            # given by the string obtained by interpreting the /name/ byte
            # array as a UTF-8 stream and the value given by the string
            # obtained by interpreting the /value/ byte array as a UTF-8 byte
            # stream.
            fields.setdefault(name, []).append(value)
            # 4.1 39. return to the "Field" step above
        return fields

    def _read_name(self):
        # 4.1 33. let /name/ be empty byte arrays
        name = ''
        while True:
            # 4.1 34. read a byte from the server
            ch = _receive_bytes(self._socket, 1)
            if ch == '\r':  # 0x0D
                return None
            elif ch == '\n':  # 0x0A
                raise ClientHandshakeError(
                    'Unexpected LF when reading header name %r' % name)
            elif ch == ':':  # 0x3A
                return name
            elif ch >= 'A' and ch <= 'Z':  # Range 0x31 to 0x5A
                ch = chr(ord(ch) + 0x20)
                name += ch
            else:
                name += ch

    def _skip_spaces(self):
        # 4.1 35. read a byte from the server
        while True:
            ch = _receive_bytes(self._socket, 1)
            if ch == ' ':  # 0x20
                continue
            return ch

    def _read_value(self, ch):
        # 4.1 33. let /value/ be empty byte arrays
        value = ''
        # 4.1 36. read a byte from server.
        while True:
            if ch == '\r':  # 0x0D
                return value
            elif ch == '\n':  # 0x0A
                raise ClientHandshakeError(
                    'Unexpected LF when reading header value %r' % value)
            else:
                value += ch
            ch = _receive_bytes(self._socket, 1)


def _get_permessage_deflate_framer(extension_response):
    """Validate the response and return a framer object using the parameters in
    the response. This method doesn't accept the server_.* parameters.
    """

    client_max_window_bits = None
    client_no_context_takeover = None

    client_max_window_bits_name = (
            PerMessageDeflateExtensionProcessor.
                    _CLIENT_MAX_WINDOW_BITS_PARAM)
    client_no_context_takeover_name = (
            PerMessageDeflateExtensionProcessor.
                    _CLIENT_NO_CONTEXT_TAKEOVER_PARAM)

    # We didn't send any server_.* parameter.
    # Handle those parameters as invalid if found in the response.

    for param_name, param_value in extension_response.get_parameters():
        if param_name == client_max_window_bits_name:
            if client_max_window_bits is not None:
                raise ClientHandshakeError(
                        'Multiple %s found' % client_max_window_bits_name)

            parsed_value = _parse_window_bits(param_value)
            if parsed_value is None:
                raise ClientHandshakeError(
                        'Bad %s: %r' %
                        (client_max_window_bits_name, param_value))
            client_max_window_bits = parsed_value
        elif param_name == client_no_context_takeover_name:
            if client_no_context_takeover is not None:
                raise ClientHandshakeError(
                        'Multiple %s found' % client_no_context_takeover_name)

            if param_value is not None:
                raise ClientHandshakeError(
                        'Bad %s: Has value %r' %
                        (client_no_context_takeover_name, param_value))
            client_no_context_takeover = True

    if client_no_context_takeover is None:
        client_no_context_takeover = False

    return _PerMessageDeflateFramer(client_max_window_bits,
                                    client_no_context_takeover)


class ClientHandshakeProcessor(ClientHandshakeBase):
    """WebSocket opening handshake processor for
    draft-ietf-hybi-thewebsocketprotocol-06 and later.
    """

    def __init__(self, socket, options):
        super(ClientHandshakeProcessor, self).__init__()

        self._socket = socket
        self._options = options

        self._logger = util.get_class_logger(self)

    def handshake(self):
        """Performs opening handshake on the specified socket.

        Raises:
            ClientHandshakeError: handshake failed.
        """

        request_line = _build_method_line(self._options.resource)
        self._logger.debug('Client\'s opening handshake Request-Line: %r',
                           request_line)
        self._socket.sendall(request_line)

        fields = []
        fields.append(_format_host_header(
            self._options.server_host,
            self._options.server_port,
            self._options.use_tls))
        fields.append(_UPGRADE_HEADER)
        fields.append(_CONNECTION_HEADER)
        if self._options.origin is not None:
            if self._options.protocol_version == _PROTOCOL_VERSION_HYBI08:
                fields.append(_origin_header(
                    common.SEC_WEBSOCKET_ORIGIN_HEADER,
                    self._options.origin))
            else:
                fields.append(_origin_header(common.ORIGIN_HEADER,
                                             self._options.origin))

        original_key = os.urandom(16)
        self._key = base64.b64encode(original_key)
        self._logger.debug(
            '%s: %r (%s)',
            common.SEC_WEBSOCKET_KEY_HEADER,
            self._key,
            util.hexify(original_key))
        fields.append(
            '%s: %s\r\n' % (common.SEC_WEBSOCKET_KEY_HEADER, self._key))

        if self._options.version_header > 0:
            fields.append('%s: %d\r\n' % (common.SEC_WEBSOCKET_VERSION_HEADER,
                                          self._options.version_header))
        elif self._options.protocol_version == _PROTOCOL_VERSION_HYBI08:
            fields.append('%s: %d\r\n' % (common.SEC_WEBSOCKET_VERSION_HEADER,
                                          common.VERSION_HYBI08))
        else:
            fields.append('%s: %d\r\n' % (common.SEC_WEBSOCKET_VERSION_HEADER,
                                          common.VERSION_HYBI_LATEST))

        extensions_to_request = []

        if self._options.deflate_frame:
            extensions_to_request.append(
                common.ExtensionParameter(common.DEFLATE_FRAME_EXTENSION))

        if self._options.use_permessage_deflate:
            extension = common.ExtensionParameter(
                    common.PERMESSAGE_DEFLATE_EXTENSION)
            # Accept the client_max_window_bits extension parameter by default.
            extension.add_parameter(
                    PerMessageDeflateExtensionProcessor.
                            _CLIENT_MAX_WINDOW_BITS_PARAM,
                    None)
            extensions_to_request.append(extension)

        if len(extensions_to_request) != 0:
            fields.append(
                '%s: %s\r\n' %
                (common.SEC_WEBSOCKET_EXTENSIONS_HEADER,
                 common.format_extensions(extensions_to_request)))

        for field in fields:
            self._socket.sendall(field)

        self._socket.sendall('\r\n')

        self._logger.debug('Sent client\'s opening handshake headers: %r',
                           fields)
        self._logger.debug('Start reading Status-Line')

        status_line = ''
        while True:
            ch = _receive_bytes(self._socket, 1)
            status_line += ch
            if ch == '\n':
                break

        m = re.match('HTTP/\\d+\.\\d+ (\\d\\d\\d) .*\r\n', status_line)
        if m is None:
            raise ClientHandshakeError(
                'Wrong status line format: %r' % status_line)
        status_code = m.group(1)
        if status_code != '101':
            self._logger.debug('Unexpected status code %s with following '
                               'headers: %r', status_code, self._read_fields())
            raise ClientHandshakeError(
                'Expected HTTP status code 101 but found %r' % status_code)

        self._logger.debug('Received valid Status-Line')
        self._logger.debug('Start reading headers until we see an empty line')

        fields = self._read_fields()

        ch = _receive_bytes(self._socket, 1)
        if ch != '\n':  # 0x0A
            raise ClientHandshakeError(
                'Expected LF but found %r while reading value %r for header '
                'name %r' % (ch, value, name))

        self._logger.debug('Received an empty line')
        self._logger.debug('Server\'s opening handshake headers: %r', fields)

        _validate_mandatory_header(
            fields,
            common.UPGRADE_HEADER,
            common.WEBSOCKET_UPGRADE_TYPE,
            False)

        _validate_mandatory_header(
            fields,
            common.CONNECTION_HEADER,
            common.UPGRADE_CONNECTION_TYPE,
            False)

        accept = _get_mandatory_header(
            fields, common.SEC_WEBSOCKET_ACCEPT_HEADER)

        # Validate
        try:
            binary_accept = base64.b64decode(accept)
        except TypeError, e:
            raise HandshakeError(
                'Illegal value for header %s: %r' %
                (common.SEC_WEBSOCKET_ACCEPT_HEADER, accept))

        if len(binary_accept) != 20:
            raise ClientHandshakeError(
                'Decoded value of %s is not 20-byte long' %
                common.SEC_WEBSOCKET_ACCEPT_HEADER)

        self._logger.debug(
            'Response for challenge : %r (%s)',
            accept, util.hexify(binary_accept))

        binary_expected_accept = util.sha1_hash(
            self._key + common.WEBSOCKET_ACCEPT_UUID).digest()
        expected_accept = base64.b64encode(binary_expected_accept)

        self._logger.debug(
            'Expected response for challenge: %r (%s)',
            expected_accept, util.hexify(binary_expected_accept))

        if accept != expected_accept:
            raise ClientHandshakeError(
                'Invalid %s header: %r (expected: %s)' %
                (common.SEC_WEBSOCKET_ACCEPT_HEADER, accept, expected_accept))

        deflate_frame_accepted = False
        permessage_deflate_accepted = False

        extensions_header = fields.get(
            common.SEC_WEBSOCKET_EXTENSIONS_HEADER.lower())
        accepted_extensions = []
        if extensions_header is not None and len(extensions_header) != 0:
            accepted_extensions = common.parse_extensions(extensions_header[0])

        # TODO(bashi): Support the new style perframe compression extension.
        for extension in accepted_extensions:
            extension_name = extension.name()
            if (extension_name == common.DEFLATE_FRAME_EXTENSION and
                self._options.deflate_frame):
                deflate_frame_accepted = True
                processor = DeflateFrameExtensionProcessor(extension)
                unused_extension_response = processor.get_extension_response()
                self._options.deflate_frame = processor
                continue
            elif (extension_name == common.PERMESSAGE_DEFLATE_EXTENSION and
                  self._options.use_permessage_deflate):
                permessage_deflate_accepted = True

                framer = _get_permessage_deflate_framer(extension)
                framer.set_compress_outgoing_enabled(True)
                self._options.use_permessage_deflate = framer
                continue

            raise ClientHandshakeError(
                'Unexpected extension %r' % extension_name)

        if (self._options.deflate_frame and not deflate_frame_accepted):
            raise ClientHandshakeError(
                'Requested %s, but the server rejected it' %
                common.DEFLATE_FRAME_EXTENSION)

        if (self._options.use_permessage_deflate and
            not permessage_deflate_accepted):
            raise ClientHandshakeError(
                    'Requested %s, but the server rejected it' %
                    common.PERMESSAGE_DEFLATE_EXTENSION)

        # TODO(tyoshino): Handle Sec-WebSocket-Protocol
        # TODO(tyoshino): Handle Cookie, etc.


class ClientHandshakeProcessorHybi00(ClientHandshakeBase):
    """WebSocket opening handshake processor for
    draft-ietf-hybi-thewebsocketprotocol-00 (equivalent to
    draft-hixie-thewebsocketprotocol-76).
    """

    def __init__(self, socket, options):
        super(ClientHandshakeProcessorHybi00, self).__init__()

        self._socket = socket
        self._options = options

        self._logger = util.get_class_logger(self)

        if (self._options.deflate_frame or
            self._options.use_permessage_deflate):
            logging.critical('HyBi 00 doesn\'t support extensions.')
            sys.exit(1)

    def handshake(self):
        """Performs opening handshake on the specified socket.

        Raises:
            ClientHandshakeError: handshake failed.
        """

        # 4.1 5. send request line.
        self._socket.sendall(_build_method_line(self._options.resource))
        # 4.1 6. Let /fields/ be an empty list of strings.
        fields = []
        # 4.1 7. Add the string "Upgrade: WebSocket" to /fields/.
        fields.append(_UPGRADE_HEADER_HIXIE75)
        # 4.1 8. Add the string "Connection: Upgrade" to /fields/.
        fields.append(_CONNECTION_HEADER)
        # 4.1 9-12. Add Host: field to /fields/.
        fields.append(_format_host_header(
            self._options.server_host,
            self._options.server_port,
            self._options.use_tls))
        # 4.1 13. Add Origin: field to /fields/.
        if not self._options.origin:
            raise ClientHandshakeError(
                'Specify the origin of the connection by --origin flag')
        fields.append(_origin_header(common.ORIGIN_HEADER,
                                     self._options.origin))
        # TODO: 4.1 14 Add Sec-WebSocket-Protocol: field to /fields/.
        # TODO: 4.1 15 Add cookie headers to /fields/.

        # 4.1 16-23. Add Sec-WebSocket-Key<n> to /fields/.
        self._number1, key1 = self._generate_sec_websocket_key()
        self._logger.debug('Number1: %d', self._number1)
        fields.append('%s: %s\r\n' % (common.SEC_WEBSOCKET_KEY1_HEADER, key1))
        self._number2, key2 = self._generate_sec_websocket_key()
        self._logger.debug('Number2: %d', self._number2)
        fields.append('%s: %s\r\n' % (common.SEC_WEBSOCKET_KEY2_HEADER, key2))

        fields.append('%s: 0\r\n' % common.SEC_WEBSOCKET_DRAFT_HEADER)

        # 4.1 24. For each string in /fields/, in a random order: send the
        # string, encoded as UTF-8, followed by a UTF-8 encoded U+000D CARRIAGE
        # RETURN U+000A LINE FEED character pair (CRLF).
        random.shuffle(fields)
        for field in fields:
            self._socket.sendall(field)
        # 4.1 25. send a UTF-8-encoded U+000D CARRIAGE RETURN U+000A LINE FEED
        # character pair (CRLF).
        self._socket.sendall('\r\n')
        # 4.1 26. let /key3/ be a string consisting of eight random bytes (or
        # equivalently, a random 64 bit integer encoded in a big-endian order).
        self._key3 = self._generate_key3()
        # 4.1 27. send /key3/ to the server.
        self._socket.sendall(self._key3)
        self._logger.debug(
            'Key3: %r (%s)', self._key3, util.hexify(self._key3))

        self._logger.info('Sent handshake')

        # 4.1 28. Read bytes from the server until either the connection
        # closes, or a 0x0A byte is read. let /field/ be these bytes, including
        # the 0x0A bytes.
        field = ''
        while True:
            ch = _receive_bytes(self._socket, 1)
            field += ch
            if ch == '\n':
                break
        # if /field/ is not at least seven bytes long, or if the last
        # two bytes aren't 0x0D and 0x0A respectively, or if it does not
        # contain at least two 0x20 bytes, then fail the WebSocket connection
        # and abort these steps.
        if len(field) < 7 or not field.endswith('\r\n'):
            raise ClientHandshakeError('Wrong status line: %r' % field)
        m = re.match('[^ ]* ([^ ]*) .*', field)
        if m is None:
            raise ClientHandshakeError(
                'No HTTP status code found in status line: %r' % field)
        # 4.1 29. let /code/ be the substring of /field/ that starts from the
        # byte after the first 0x20 byte, and ends with the byte before the
        # second 0x20 byte.
        code = m.group(1)
        # 4.1 30. if /code/ is not three bytes long, or if any of the bytes in
        # /code/ are not in the range 0x30 to 0x90, then fail the WebSocket
        # connection and abort these steps.
        if not re.match('[0-9][0-9][0-9]', code):
            raise ClientHandshakeError(
                'HTTP status code %r is not three digit in status line: %r' %
                (code, field))
        # 4.1 31. if /code/, interpreted as UTF-8, is "101", then move to the
        # next step.
        if code != '101':
            raise ClientHandshakeError(
                'Expected HTTP status code 101 but found %r in status line: '
                '%r' % (code, field))
        # 4.1 32-39. read fields into /fields/
        fields = self._read_fields()
        # 4.1 40. _Fields processing_
        # read a byte from server
        ch = _receive_bytes(self._socket, 1)
        if ch != '\n':  # 0x0A
            raise ClientHandshakeError('Expected LF but found %r' % ch)
        # 4.1 41. check /fields/
        # TODO(ukai): protocol
        # if the entry's name is "upgrade"
        #  if the value is not exactly equal to the string "WebSocket",
        #  then fail the WebSocket connection and abort these steps.
        _validate_mandatory_header(
            fields,
            common.UPGRADE_HEADER,
            common.WEBSOCKET_UPGRADE_TYPE_HIXIE75,
            True)
        # if the entry's name is "connection"
        #  if the value, converted to ASCII lowercase, is not exactly equal
        #  to the string "upgrade", then fail the WebSocket connection and
        #  abort these steps.
        _validate_mandatory_header(
            fields,
            common.CONNECTION_HEADER,
            common.UPGRADE_CONNECTION_TYPE,
            False)

        origin = _get_mandatory_header(
            fields, common.SEC_WEBSOCKET_ORIGIN_HEADER)

        location = _get_mandatory_header(
            fields, common.SEC_WEBSOCKET_LOCATION_HEADER)

        # TODO(ukai): check origin, location, cookie, ..

        # 4.1 42. let /challenge/ be the concatenation of /number_1/,
        # expressed as a big endian 32 bit integer, /number_2/, expressed
        # as big endian 32 bit integer, and the eight bytes of /key_3/ in the
        # order they were sent on the wire.
        challenge = struct.pack('!I', self._number1)
        challenge += struct.pack('!I', self._number2)
        challenge += self._key3

        self._logger.debug(
            'Challenge: %r (%s)', challenge, util.hexify(challenge))

        # 4.1 43. let /expected/ be the MD5 fingerprint of /challenge/ as a
        # big-endian 128 bit string.
        expected = util.md5_hash(challenge).digest()
        self._logger.debug(
            'Expected challenge response: %r (%s)',
            expected, util.hexify(expected))

        # 4.1 44. read sixteen bytes from the server.
        # let /reply/ be those bytes.
        reply = _receive_bytes(self._socket, 16)
        self._logger.debug(
            'Actual challenge response: %r (%s)', reply, util.hexify(reply))

        # 4.1 45. if /reply/ does not exactly equal /expected/, then fail
        # the WebSocket connection and abort these steps.
        if expected != reply:
            raise ClientHandshakeError(
                'Bad challenge response: %r (expected) != %r (actual)' %
                (expected, reply))
        # 4.1 46. The *WebSocket connection is established*.

    def _generate_sec_websocket_key(self):
        # 4.1 16. let /spaces_n/ be a random integer from 1 to 12 inclusive.
        spaces = random.randint(1, 12)
        # 4.1 17. let /max_n/ be the largest integer not greater than
        #  4,294,967,295 divided by /spaces_n/.
        maxnum = 4294967295 / spaces
        # 4.1 18. let /number_n/ be a random integer from 0 to /max_n/
        # inclusive.
        number = random.randint(0, maxnum)
        # 4.1 19. let /product_n/ be the result of multiplying /number_n/ and
        # /spaces_n/ together.
        product = number * spaces
        # 4.1 20. let /key_n/ be a string consisting of /product_n/, expressed
        # in base ten using the numerals in the range U+0030 DIGIT ZERO (0) to
        # U+0039 DIGIT NINE (9).
        key = str(product)
        # 4.1 21. insert between one and twelve random characters from the
        # range U+0021 to U+002F and U+003A to U+007E into /key_n/ at random
        # positions.
        available_chars = range(0x21, 0x2f + 1) + range(0x3a, 0x7e + 1)
        n = random.randint(1, 12)
        for _ in xrange(n):
            ch = random.choice(available_chars)
            pos = random.randint(0, len(key))
            key = key[0:pos] + chr(ch) + key[pos:]
        # 4.1 22. insert /spaces_n/ U+0020 SPACE characters into /key_n/ at
        # random positions other than start or end of the string.
        for _ in xrange(spaces):
            pos = random.randint(1, len(key) - 1)
            key = key[0:pos] + ' ' + key[pos:]
        return number, key

    def _generate_key3(self):
        # 4.1 26. let /key3/ be a string consisting of eight random bytes (or
        # equivalently, a random 64 bit integer encoded in a big-endian order).
        return ''.join([chr(random.randint(0, 255)) for _ in xrange(8)])


class ClientConnection(object):
    """A wrapper for socket object to provide the mp_conn interface.
    mod_pywebsocket library is designed to be working on Apache mod_python's
    mp_conn object.
    """

    def __init__(self, socket):
        self._socket = socket

    def write(self, data):
        self._socket.sendall(data)

    def read(self, n):
        return self._socket.recv(n)

    def get_remote_addr(self):
        return self._socket.getpeername()
    remote_addr = property(get_remote_addr)


class ClientRequest(object):
    """A wrapper class just to make it able to pass a socket object to
    functions that expect a mp_request object.
    """

    def __init__(self, socket):
        self._logger = util.get_class_logger(self)

        self._socket = socket
        self.connection = ClientConnection(socket)


def _import_ssl():
    global ssl
    try:
        import ssl
        return True
    except ImportError:
        return False


def _import_pyopenssl():
    global OpenSSL
    try:
        import OpenSSL.SSL
        return True
    except ImportError:
        return False


class EchoClient(object):
    """WebSocket echo client."""

    def __init__(self, options):
        self._options = options
        self._socket = None

        self._logger = util.get_class_logger(self)

    def run(self):
        """Run the client.

        Shake hands and then repeat sending message and receiving its echo.
        """

        self._socket = socket.socket()
        self._socket.settimeout(self._options.socket_timeout)
        try:
            self._socket.connect((self._options.server_host,
                                  self._options.server_port))
            if self._options.use_tls:
                self._socket = _TLSSocket(
                    self._socket,
                    self._options.tls_module,
                    self._options.tls_version,
                    self._options.disable_tls_compression)

            version = self._options.protocol_version

            if (version == _PROTOCOL_VERSION_HYBI08 or
                version == _PROTOCOL_VERSION_HYBI13):
                self._handshake = ClientHandshakeProcessor(
                    self._socket, self._options)
            elif version == _PROTOCOL_VERSION_HYBI00:
                self._handshake = ClientHandshakeProcessorHybi00(
                    self._socket, self._options)
            else:
                raise ValueError(
                    'Invalid --protocol-version flag: %r' % version)

            self._handshake.handshake()

            self._logger.info('Connection established')

            request = ClientRequest(self._socket)

            version_map = {
                _PROTOCOL_VERSION_HYBI08: common.VERSION_HYBI08,
                _PROTOCOL_VERSION_HYBI13: common.VERSION_HYBI13,
                _PROTOCOL_VERSION_HYBI00: common.VERSION_HYBI00}
            request.ws_version = version_map[version]

            if (version == _PROTOCOL_VERSION_HYBI08 or
                version == _PROTOCOL_VERSION_HYBI13):
                stream_option = StreamOptions()
                stream_option.mask_send = True
                stream_option.unmask_receive = False

                if self._options.deflate_frame is not False:
                    processor = self._options.deflate_frame
                    processor.setup_stream_options(stream_option)

                if self._options.use_permessage_deflate is not False:
                    framer = self._options.use_permessage_deflate
                    framer.setup_stream_options(stream_option)

                self._stream = Stream(request, stream_option)
            elif version == _PROTOCOL_VERSION_HYBI00:
                self._stream = StreamHixie75(request, True)

            for line in self._options.message.split(','):
                self._stream.send_message(line)
                if self._options.verbose:
                    print 'Send: %s' % line
                try:
                    received = self._stream.receive_message()

                    if self._options.verbose:
                        print 'Recv: %s' % received
                except Exception, e:
                    if self._options.verbose:
                        print 'Error: %s' % e
                    raise

            self._do_closing_handshake()
        finally:
            self._socket.close()

    def _do_closing_handshake(self):
        """Perform closing handshake using the specified closing frame."""

        if self._options.message.split(',')[-1] == _GOODBYE_MESSAGE:
            # requested server initiated closing handshake, so
            # expecting closing handshake message from server.
            self._logger.info('Wait for server-initiated closing handshake')
            message = self._stream.receive_message()
            if message is None:
                print 'Recv close'
                print 'Send ack'
                self._logger.info(
                    'Received closing handshake and sent ack')
                return
        print 'Send close'
        self._stream.close_connection()
        self._logger.info('Sent closing handshake')
        print 'Recv ack'
        self._logger.info('Received ack')


def main():
    sys.stdout = codecs.getwriter('utf-8')(sys.stdout)

    parser = OptionParser()
    # We accept --command_line_flag style flags which is the same as Google
    # gflags in addition to common --command-line-flag style flags.
    parser.add_option('-s', '--server-host', '--server_host',
                      dest='server_host', type='string',
                      default='localhost', help='server host')
    parser.add_option('-p', '--server-port', '--server_port',
                      dest='server_port', type='int',
                      default=_UNDEFINED_PORT, help='server port')
    parser.add_option('-o', '--origin', dest='origin', type='string',
                      default=None, help='origin')
    parser.add_option('-r', '--resource', dest='resource', type='string',
                      default='/echo', help='resource path')
    parser.add_option('-m', '--message', dest='message', type='string',
                      help=('comma-separated messages to send. '
                           '%s will force close the connection from server.' %
                            _GOODBYE_MESSAGE))
    parser.add_option('-q', '--quiet', dest='verbose', action='store_false',
                      default=True, help='suppress messages')
    parser.add_option('-t', '--tls', dest='use_tls', action='store_true',
                      default=False, help='use TLS (wss://). By default, '
                      'it looks for ssl and pyOpenSSL module and uses found '
                      'one. Use --tls-module option to specify which module '
                      'to use')
    parser.add_option('--tls-module', '--tls_module', dest='tls_module',
                      type='choice',
                      choices=[_TLS_BY_STANDARD_MODULE, _TLS_BY_PYOPENSSL],
                      help='Use ssl module if "%s" is specified. '
                      'Use pyOpenSSL module if "%s" is specified' %
                      (_TLS_BY_STANDARD_MODULE, _TLS_BY_PYOPENSSL))
    parser.add_option('--tls-version', '--tls_version',
                      dest='tls_version',
                      type='string', default=_TLS_VERSION_SSL23,
                      help='TLS/SSL version to use. One of \'' +
                      _TLS_VERSION_SSL23 + '\' (SSL version 2 or 3), \'' +
                      _TLS_VERSION_SSL3 + '\' (SSL version 3), \'' +
                      _TLS_VERSION_TLS1 + '\' (TLS version 1)')
    parser.add_option('--disable-tls-compression', '--disable_tls_compression',
                      dest='disable_tls_compression',
                      action='store_true', default=False,
                      help='Disable TLS compression. Available only when '
                      'pyOpenSSL module is used.')
    parser.add_option('-k', '--socket-timeout', '--socket_timeout',
                      dest='socket_timeout', type='int', default=_TIMEOUT_SEC,
                      help='Timeout(sec) for sockets')
    parser.add_option('--draft75', dest='draft75',
                      action='store_true', default=False,
                      help='Obsolete option. Don\'t use this.')
    parser.add_option('--protocol-version', '--protocol_version',
                      dest='protocol_version',
                      type='string', default=_PROTOCOL_VERSION_HYBI13,
                      help='WebSocket protocol version to use. One of \'' +
                      _PROTOCOL_VERSION_HYBI13 + '\', \'' +
                      _PROTOCOL_VERSION_HYBI08 + '\', \'' +
                      _PROTOCOL_VERSION_HYBI00 + '\'')
    parser.add_option('--version-header', '--version_header',
                      dest='version_header',
                      type='int', default=-1,
                      help='Specify Sec-WebSocket-Version header value')
    parser.add_option('--deflate-frame', '--deflate_frame',
                      dest='deflate_frame',
                      action='store_true', default=False,
                      help='Use the deflate-frame extension.')
    parser.add_option('--use-permessage-deflate', '--use_permessage_deflate',
                      dest='use_permessage_deflate',
                      action='store_true', default=False,
                      help='Use the permessage-deflate extension.')
    parser.add_option('--log-level', '--log_level', type='choice',
                      dest='log_level', default='warn',
                      choices=['debug', 'info', 'warn', 'error', 'critical'],
                      help='Log level.')

    (options, unused_args) = parser.parse_args()

    logging.basicConfig(level=logging.getLevelName(options.log_level.upper()))

    if options.draft75:
        logging.critical('--draft75 option is obsolete.')
        sys.exit(1)

    if options.protocol_version == _PROTOCOL_VERSION_HIXIE75:
        logging.critical(
            'Value %s is obsolete for --protocol_version options' %
            _PROTOCOL_VERSION_HIXIE75)
        sys.exit(1)

    if options.use_tls:
        if options.tls_module is None:
            if _import_ssl():
                options.tls_module = _TLS_BY_STANDARD_MODULE
                logging.debug('Using ssl module')
            elif _import_pyopenssl():
                options.tls_module = _TLS_BY_PYOPENSSL
                logging.debug('Using pyOpenSSL module')
            else:
                logging.critical(
                        'TLS support requires ssl or pyOpenSSL module.')
                sys.exit(1)
        elif options.tls_module == _TLS_BY_STANDARD_MODULE:
            if not _import_ssl():
                logging.critical('ssl module is not available')
                sys.exit(1)
        elif options.tls_module == _TLS_BY_PYOPENSSL:
            if not _import_pyopenssl():
                logging.critical('pyOpenSSL module is not available')
                sys.exit(1)
        else:
            logging.critical('Invalid --tls-module option: %r',
                             options.tls_module)
            sys.exit(1)

        if (options.disable_tls_compression and
            options.tls_module != _TLS_BY_PYOPENSSL):
            logging.critical('You can disable TLS compression only when '
                             'pyOpenSSL module is used.')
            sys.exit(1)
    else:
        if options.tls_module is not None:
            logging.critical('Use --tls-module option only together with '
                             '--use-tls option.')
            sys.exit(1)

        if options.disable_tls_compression:
            logging.critical('Use --disable-tls-compression only together '
                             'with --use-tls option.')
            sys.exit(1)

    # Default port number depends on whether TLS is used.
    if options.server_port == _UNDEFINED_PORT:
        if options.use_tls:
            options.server_port = common.DEFAULT_WEB_SOCKET_SECURE_PORT
        else:
            options.server_port = common.DEFAULT_WEB_SOCKET_PORT

    # optparse doesn't seem to handle non-ascii default values.
    # Set default message here.
    if not options.message:
        options.message = u'Hello,\u65e5\u672c'   # "Japan" in Japanese

    EchoClient(options).run()


if __name__ == '__main__':
    main()


# vi:sts=4 sw=4 et