| # 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 |
| # 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. |
| |
| |
| """WebSocket handshaking defined in draft-hixie-thewebsocketprotocol-75.""" |
| |
| |
| # Note: request.connection.write is used in this module, even though mod_python |
| # document says that it should be used only in connection handlers. |
| # Unfortunately, we have no other options. For example, request.write is not |
| # suitable because it doesn't allow direct raw bytes writing. |
| |
| |
| import logging |
| import re |
| |
| from mod_pywebsocket import common |
| from mod_pywebsocket.stream import StreamHixie75 |
| from mod_pywebsocket import util |
| from mod_pywebsocket.handshake._base import HandshakeException |
| from mod_pywebsocket.handshake._base import build_location |
| from mod_pywebsocket.handshake._base import validate_subprotocol |
| |
| |
| _MANDATORY_HEADERS = [ |
| # key, expected value or None |
| ['Upgrade', 'WebSocket'], |
| ['Connection', 'Upgrade'], |
| ['Host', None], |
| ['Origin', None], |
| ] |
| |
| _FIRST_FIVE_LINES = map(re.compile, [ |
| r'^GET /[\S]* HTTP/1.1\r\n$', |
| r'^Upgrade: WebSocket\r\n$', |
| r'^Connection: Upgrade\r\n$', |
| r'^Host: [\S]+\r\n$', |
| r'^Origin: [\S]+\r\n$', |
| ]) |
| |
| _SIXTH_AND_LATER = re.compile( |
| r'^' |
| r'(WebSocket-Protocol: [\x20-\x7e]+\r\n)?' |
| r'(Cookie: [^\r]*\r\n)*' |
| r'(Cookie2: [^\r]*\r\n)?' |
| r'(Cookie: [^\r]*\r\n)*' |
| r'\r\n') |
| |
| |
| class Handshaker(object): |
| """This class performs WebSocket handshake.""" |
| |
| def __init__(self, request, dispatcher, strict=False): |
| """Construct an instance. |
| |
| Args: |
| request: mod_python request. |
| dispatcher: Dispatcher (dispatch.Dispatcher). |
| strict: Strictly check handshake request. Default: False. |
| If True, request.connection must provide get_memorized_lines |
| method. |
| |
| Handshaker will add attributes such as ws_resource in performing |
| handshake. |
| """ |
| |
| self._logger = util.get_class_logger(self) |
| |
| self._request = request |
| self._dispatcher = dispatcher |
| self._strict = strict |
| |
| def do_handshake(self): |
| """Perform WebSocket Handshake. |
| |
| On _request, we set |
| ws_resource, ws_origin, ws_location, ws_protocol |
| ws_challenge_md5: WebSocket handshake information. |
| ws_stream: Frame generation/parsing class. |
| ws_version: Protocol version. |
| """ |
| |
| self._check_header_lines() |
| self._set_resource() |
| self._set_origin() |
| self._set_location() |
| self._set_subprotocol() |
| self._set_protocol_version() |
| |
| self._dispatcher.do_extra_handshake(self._request) |
| |
| self._send_handshake() |
| |
| self._logger.debug('Sent opening handshake response') |
| |
| def _set_resource(self): |
| self._request.ws_resource = self._request.uri |
| |
| def _set_origin(self): |
| self._request.ws_origin = self._request.headers_in['Origin'] |
| |
| def _set_location(self): |
| self._request.ws_location = build_location(self._request) |
| |
| def _set_subprotocol(self): |
| subprotocol = self._request.headers_in.get('WebSocket-Protocol') |
| if subprotocol is not None: |
| validate_subprotocol(subprotocol, hixie=True) |
| self._request.ws_protocol = subprotocol |
| |
| def _set_protocol_version(self): |
| self._logger.debug('IETF Hixie 75 protocol') |
| self._request.ws_version = common.VERSION_HIXIE75 |
| self._request.ws_stream = StreamHixie75(self._request) |
| |
| def _sendall(self, data): |
| self._request.connection.write(data) |
| |
| def _send_handshake(self): |
| self._sendall('HTTP/1.1 101 Web Socket Protocol Handshake\r\n') |
| self._sendall('Upgrade: WebSocket\r\n') |
| self._sendall('Connection: Upgrade\r\n') |
| self._sendall('WebSocket-Origin: %s\r\n' % self._request.ws_origin) |
| self._sendall('WebSocket-Location: %s\r\n' % self._request.ws_location) |
| if self._request.ws_protocol: |
| self._sendall( |
| 'WebSocket-Protocol: %s\r\n' % self._request.ws_protocol) |
| self._sendall('\r\n') |
| |
| def _check_header_lines(self): |
| for key, expected_value in _MANDATORY_HEADERS: |
| actual_value = self._request.headers_in.get(key) |
| if not actual_value: |
| raise HandshakeException('Header %s is not defined' % key) |
| if expected_value: |
| if actual_value != expected_value: |
| raise HandshakeException( |
| 'Expected %r for header %s but found %r' % |
| (expected_value, key, actual_value)) |
| if self._strict: |
| try: |
| lines = self._request.connection.get_memorized_lines() |
| except AttributeError, e: |
| raise AttributeError( |
| 'Strict handshake is specified but the connection ' |
| 'doesn\'t provide get_memorized_lines()') |
| self._check_first_lines(lines) |
| |
| def _check_first_lines(self, lines): |
| if len(lines) < len(_FIRST_FIVE_LINES): |
| raise HandshakeException('Too few header lines: %d' % len(lines)) |
| for line, regexp in zip(lines, _FIRST_FIVE_LINES): |
| if not regexp.search(line): |
| raise HandshakeException( |
| 'Unexpected header: %r doesn\'t match %r' |
| % (line, regexp.pattern)) |
| sixth_and_later = ''.join(lines[5:]) |
| if not _SIXTH_AND_LATER.search(sixth_and_later): |
| raise HandshakeException( |
| 'Unexpected header: %r doesn\'t match %r' |
| % (sixth_and_later, _SIXTH_AND_LATER.pattern)) |
| |
| |
| # vi:sts=4 sw=4 et |
