# Copyright 2010, 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. """Web Socket handshaking defined in draft-hixie-thewebsocketprotocol-75. Note: request.connection.write/read are used in this module, even though mod_python document says that they should be used only in connection handlers. Unfortunately, we have no other options. For example, request.write/read are not suitable because they don't allow direct raw bytes writing/reading. """ import re from mod_pywebsocket.handshake._base import HandshakeError from mod_pywebsocket.handshake._base import build_location from mod_pywebsocket.handshake._base import validate_protocol _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 Web Socket 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._request = request self._dispatcher = dispatcher self._strict = strict def do_handshake(self): """Perform Web Socket Handshake.""" self._check_header_lines() self._set_resource() self._set_origin() self._set_location() self._set_protocol() self._dispatcher.do_extra_handshake(self._request) self._send_handshake() 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_protocol(self): protocol = self._request.headers_in.get('WebSocket-Protocol') if protocol is not None: validate_protocol(protocol) self._request.ws_protocol = protocol def _send_handshake(self): self._request.connection.write( 'HTTP/1.1 101 Web Socket Protocol Handshake\r\n') self._request.connection.write('Upgrade: WebSocket\r\n') self._request.connection.write('Connection: Upgrade\r\n') self._request.connection.write('WebSocket-Origin: ') self._request.connection.write(self._request.ws_origin) self._request.connection.write('\r\n') self._request.connection.write('WebSocket-Location: ') self._request.connection.write(self._request.ws_location) self._request.connection.write('\r\n') if self._request.ws_protocol: self._request.connection.write('WebSocket-Protocol: ') self._request.connection.write(self._request.ws_protocol) self._request.connection.write('\r\n') self._request.connection.write('\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 HandshakeError('Header %s is not defined' % key) if expected_value: if actual_value != expected_value: raise HandshakeError('Illegal value for header %s: %s' % (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 HandshakeError('Too few header lines: %d' % len(lines)) for line, regexp in zip(lines, _FIRST_FIVE_LINES): if not regexp.search(line): raise HandshakeError('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 HandshakeError('Unexpected header: %r doesn\'t match %r' % (sixth_and_later, _SIXTH_AND_LATER.pattern)) # vi:sts=4 sw=4 et