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# 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.
"""PythonHeaderParserHandler for mod_pywebsocket.
Apache HTTP Server and mod_python must be configured such that this
function is called to handle WebSocket request.
"""
import logging
from mod_python import apache
from mod_pywebsocket import common
from mod_pywebsocket import dispatch
from mod_pywebsocket import handshake
from mod_pywebsocket import util
# PythonOption to specify the handler root directory.
_PYOPT_HANDLER_ROOT = 'mod_pywebsocket.handler_root'
# PythonOption to specify the handler scan directory.
# This must be a directory under the root directory.
# The default is the root directory.
_PYOPT_HANDLER_SCAN = 'mod_pywebsocket.handler_scan'
# PythonOption to allow handlers whose canonical path is
# not under the root directory. It's disallowed by default.
# Set this option with value of 'yes' to allow.
_PYOPT_ALLOW_HANDLERS_OUTSIDE_ROOT = (
'mod_pywebsocket.allow_handlers_outside_root_dir')
# Map from values to their meanings. 'Yes' and 'No' are allowed just for
# compatibility.
_PYOPT_ALLOW_HANDLERS_OUTSIDE_ROOT_DEFINITION = {
'off': False, 'no': False, 'on': True, 'yes': True}
# (Obsolete option. Ignored.)
# PythonOption to specify to allow handshake defined in Hixie 75 version
# protocol. The default is None (Off)
_PYOPT_ALLOW_DRAFT75 = 'mod_pywebsocket.allow_draft75'
# Map from values to their meanings.
_PYOPT_ALLOW_DRAFT75_DEFINITION = {'off': False, 'on': True}
class ApacheLogHandler(logging.Handler):
"""Wrapper logging.Handler to emit log message to apache's error.log."""
_LEVELS = {
logging.DEBUG: apache.APLOG_DEBUG,
logging.INFO: apache.APLOG_INFO,
logging.WARNING: apache.APLOG_WARNING,
logging.ERROR: apache.APLOG_ERR,
logging.CRITICAL: apache.APLOG_CRIT,
}
def __init__(self, request=None):
logging.Handler.__init__(self)
self._log_error = apache.log_error
if request is not None:
self._log_error = request.log_error
# Time and level will be printed by Apache.
self._formatter = logging.Formatter('%(name)s: %(message)s')
def emit(self, record):
apache_level = apache.APLOG_DEBUG
if record.levelno in ApacheLogHandler._LEVELS:
apache_level = ApacheLogHandler._LEVELS[record.levelno]
msg = self._formatter.format(record)
# "server" parameter must be passed to have "level" parameter work.
# If only "level" parameter is passed, nothing shows up on Apache's
# log. However, at this point, we cannot get the server object of the
# virtual host which will process WebSocket requests. The only server
# object we can get here is apache.main_server. But Wherever (server
# configuration context or virtual host context) we put
# PythonHeaderParserHandler directive, apache.main_server just points
# the main server instance (not any of virtual server instance). Then,
# Apache follows LogLevel directive in the server configuration context
# to filter logs. So, we need to specify LogLevel in the server
# configuration context. Even if we specify "LogLevel debug" in the
# virtual host context which actually handles WebSocket connections,
# DEBUG level logs never show up unless "LogLevel debug" is specified
# in the server configuration context.
#
# TODO(tyoshino): Provide logging methods on request object. When
# request is mp_request object (when used together with Apache), the
# methods call request.log_error indirectly. When request is
# _StandaloneRequest, the methods call Python's logging facility which
# we create in standalone.py.
self._log_error(msg, apache_level, apache.main_server)
def _configure_logging():
logger = logging.getLogger()
# Logs are filtered by Apache based on LogLevel directive in Apache
# configuration file. We must just pass logs for all levels to
# ApacheLogHandler.
logger.setLevel(logging.DEBUG)
logger.addHandler(ApacheLogHandler())
_configure_logging()
_LOGGER = logging.getLogger(__name__)
def _parse_option(name, value, definition):
if value is None:
return False
meaning = definition.get(value.lower())
if meaning is None:
raise Exception('Invalid value for PythonOption %s: %r' %
(name, value))
return meaning
def _create_dispatcher():
_LOGGER.info('Initializing Dispatcher')
options = apache.main_server.get_options()
handler_root = options.get(_PYOPT_HANDLER_ROOT, None)
if not handler_root:
raise Exception('PythonOption %s is not defined' % _PYOPT_HANDLER_ROOT,
apache.APLOG_ERR)
handler_scan = options.get(_PYOPT_HANDLER_SCAN, handler_root)
allow_handlers_outside_root = _parse_option(
_PYOPT_ALLOW_HANDLERS_OUTSIDE_ROOT,
options.get(_PYOPT_ALLOW_HANDLERS_OUTSIDE_ROOT),
_PYOPT_ALLOW_HANDLERS_OUTSIDE_ROOT_DEFINITION)
dispatcher = dispatch.Dispatcher(
handler_root, handler_scan, allow_handlers_outside_root)
for warning in dispatcher.source_warnings():
apache.log_error(
'mod_pywebsocket: Warning in source loading: %s' % warning,
apache.APLOG_WARNING)
return dispatcher
# Initialize
_dispatcher = _create_dispatcher()
def headerparserhandler(request):
"""Handle request.
Args:
request: mod_python request.
This function is named headerparserhandler because it is the default
name for a PythonHeaderParserHandler.
"""
handshake_is_done = False
try:
# Fallback to default http handler for request paths for which
# we don't have request handlers.
if not _dispatcher.get_handler_suite(request.uri):
request.log_error(
'mod_pywebsocket: No handler for resource: %r' % request.uri,
apache.APLOG_INFO)
request.log_error(
'mod_pywebsocket: Fallback to Apache', apache.APLOG_INFO)
return apache.DECLINED
except dispatch.DispatchException, e:
request.log_error(
'mod_pywebsocket: Dispatch failed for error: %s' % e,
apache.APLOG_INFO)
if not handshake_is_done:
return e.status
try:
allow_draft75 = _parse_option(
_PYOPT_ALLOW_DRAFT75,
apache.main_server.get_options().get(_PYOPT_ALLOW_DRAFT75),
_PYOPT_ALLOW_DRAFT75_DEFINITION)
try:
handshake.do_handshake(
request, _dispatcher, allowDraft75=allow_draft75)
except handshake.VersionException, e:
request.log_error(
'mod_pywebsocket: Handshake failed for version error: %s' % e,
apache.APLOG_INFO)
request.err_headers_out.add(common.SEC_WEBSOCKET_VERSION_HEADER,
e.supported_versions)
return apache.HTTP_BAD_REQUEST
except handshake.HandshakeException, e:
# Handshake for ws/wss failed.
# Send http response with error status.
request.log_error(
'mod_pywebsocket: Handshake failed for error: %s' % e,
apache.APLOG_INFO)
return e.status
handshake_is_done = True
request._dispatcher = _dispatcher
_dispatcher.transfer_data(request)
except handshake.AbortedByUserException, e:
request.log_error('mod_pywebsocket: Aborted: %s' % e, apache.APLOG_INFO)
except Exception, e:
# DispatchException can also be thrown if something is wrong in
# pywebsocket code. It's caught here, then.
request.log_error('mod_pywebsocket: Exception occurred: %s\n%s' %
(e, util.get_stack_trace()),
apache.APLOG_ERR)
# Unknown exceptions before handshake mean Apache must handle its
# request with another handler.
if not handshake_is_done:
return apache.DECLINED
# Set assbackwards to suppress response header generation by Apache.
request.assbackwards = 1
return apache.DONE # Return DONE such that no other handlers are invoked.
# vi:sts=4 sw=4 et
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