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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.
+
+
+"""Dispatch WebSocket request.
+"""
+
+
+import logging
+import os
+import re
+
+from mod_pywebsocket import common
+from mod_pywebsocket import handshake
+from mod_pywebsocket import msgutil
+from mod_pywebsocket import mux
+from mod_pywebsocket import stream
+from mod_pywebsocket import util
+
+
+_SOURCE_PATH_PATTERN = re.compile(r'(?i)_wsh\.py$')
+_SOURCE_SUFFIX = '_wsh.py'
+_DO_EXTRA_HANDSHAKE_HANDLER_NAME = 'web_socket_do_extra_handshake'
+_TRANSFER_DATA_HANDLER_NAME = 'web_socket_transfer_data'
+_PASSIVE_CLOSING_HANDSHAKE_HANDLER_NAME = (
+ 'web_socket_passive_closing_handshake')
+
+
+class DispatchException(Exception):
+ """Exception in dispatching WebSocket request."""
+
+ def __init__(self, name, status=common.HTTP_STATUS_NOT_FOUND):
+ super(DispatchException, self).__init__(name)
+ self.status = status
+
+
+def _default_passive_closing_handshake_handler(request):
+ """Default web_socket_passive_closing_handshake handler."""
+
+ return common.STATUS_NORMAL_CLOSURE, ''
+
+
+def _normalize_path(path):
+ """Normalize path.
+
+ Args:
+ path: the path to normalize.
+
+ Path is converted to the absolute path.
+ The input path can use either '\\' or '/' as the separator.
+ The normalized path always uses '/' regardless of the platform.
+ """
+
+ path = path.replace('\\', os.path.sep)
+ path = os.path.realpath(path)
+ path = path.replace('\\', '/')
+ return path
+
+
+def _create_path_to_resource_converter(base_dir):
+ """Returns a function that converts the path of a WebSocket handler source
+ file to a resource string by removing the path to the base directory from
+ its head, removing _SOURCE_SUFFIX from its tail, and replacing path
+ separators in it with '/'.
+
+ Args:
+ base_dir: the path to the base directory.
+ """
+
+ base_dir = _normalize_path(base_dir)
+
+ base_len = len(base_dir)
+ suffix_len = len(_SOURCE_SUFFIX)
+
+ def converter(path):
+ if not path.endswith(_SOURCE_SUFFIX):
+ return None
+ # _normalize_path must not be used because resolving symlink breaks
+ # following path check.
+ path = path.replace('\\', '/')
+ if not path.startswith(base_dir):
+ return None
+ return path[base_len:-suffix_len]
+
+ return converter
+
+
+def _enumerate_handler_file_paths(directory):
+ """Returns a generator that enumerates WebSocket Handler source file names
+ in the given directory.
+ """
+
+ for root, unused_dirs, files in os.walk(directory):
+ for base in files:
+ path = os.path.join(root, base)
+ if _SOURCE_PATH_PATTERN.search(path):
+ yield path
+
+
+class _HandlerSuite(object):
+ """A handler suite holder class."""
+
+ def __init__(self, do_extra_handshake, transfer_data,
+ passive_closing_handshake):
+ self.do_extra_handshake = do_extra_handshake
+ self.transfer_data = transfer_data
+ self.passive_closing_handshake = passive_closing_handshake
+
+
+def _source_handler_file(handler_definition):
+ """Source a handler definition string.
+
+ Args:
+ handler_definition: a string containing Python statements that define
+ handler functions.
+ """
+
+ global_dic = {}
+ try:
+ exec handler_definition in global_dic
+ except Exception:
+ raise DispatchException('Error in sourcing handler:' +
+ util.get_stack_trace())
+ passive_closing_handshake_handler = None
+ try:
+ passive_closing_handshake_handler = _extract_handler(
+ global_dic, _PASSIVE_CLOSING_HANDSHAKE_HANDLER_NAME)
+ except Exception:
+ passive_closing_handshake_handler = (
+ _default_passive_closing_handshake_handler)
+ return _HandlerSuite(
+ _extract_handler(global_dic, _DO_EXTRA_HANDSHAKE_HANDLER_NAME),
+ _extract_handler(global_dic, _TRANSFER_DATA_HANDLER_NAME),
+ passive_closing_handshake_handler)
+
+
+def _extract_handler(dic, name):
+ """Extracts a callable with the specified name from the given dictionary
+ dic.
+ """
+
+ if name not in dic:
+ raise DispatchException('%s is not defined.' % name)
+ handler = dic[name]
+ if not callable(handler):
+ raise DispatchException('%s is not callable.' % name)
+ return handler
+
+
+class Dispatcher(object):
+ """Dispatches WebSocket requests.
+
+ This class maintains a map from resource name to handlers.
+ """
+
+ def __init__(
+ self, root_dir, scan_dir=None,
+ allow_handlers_outside_root_dir=True):
+ """Construct an instance.
+
+ Args:
+ root_dir: The directory where handler definition files are
+ placed.
+ scan_dir: The directory where handler definition files are
+ searched. scan_dir must be a directory under root_dir,
+ including root_dir itself. If scan_dir is None,
+ root_dir is used as scan_dir. scan_dir can be useful
+ in saving scan time when root_dir contains many
+ subdirectories.
+ allow_handlers_outside_root_dir: Scans handler files even if their
+ canonical path is not under root_dir.
+ """
+
+ self._logger = util.get_class_logger(self)
+
+ self._handler_suite_map = {}
+ self._source_warnings = []
+ if scan_dir is None:
+ scan_dir = root_dir
+ if not os.path.realpath(scan_dir).startswith(
+ os.path.realpath(root_dir)):
+ raise DispatchException('scan_dir:%s must be a directory under '
+ 'root_dir:%s.' % (scan_dir, root_dir))
+ self._source_handler_files_in_dir(
+ root_dir, scan_dir, allow_handlers_outside_root_dir)
+
+ def add_resource_path_alias(self,
+ alias_resource_path, existing_resource_path):
+ """Add resource path alias.
+
+ Once added, request to alias_resource_path would be handled by
+ handler registered for existing_resource_path.
+
+ Args:
+ alias_resource_path: alias resource path
+ existing_resource_path: existing resource path
+ """
+ try:
+ handler_suite = self._handler_suite_map[existing_resource_path]
+ self._handler_suite_map[alias_resource_path] = handler_suite
+ except KeyError:
+ raise DispatchException('No handler for: %r' %
+ existing_resource_path)
+
+ def source_warnings(self):
+ """Return warnings in sourcing handlers."""
+
+ return self._source_warnings
+
+ def do_extra_handshake(self, request):
+ """Do extra checking in WebSocket handshake.
+
+ Select a handler based on request.uri and call its
+ web_socket_do_extra_handshake function.
+
+ Args:
+ request: mod_python request.
+
+ Raises:
+ DispatchException: when handler was not found
+ AbortedByUserException: when user handler abort connection
+ HandshakeException: when opening handshake failed
+ """
+
+ handler_suite = self.get_handler_suite(request.ws_resource)
+ if handler_suite is None:
+ raise DispatchException('No handler for: %r' % request.ws_resource)
+ do_extra_handshake_ = handler_suite.do_extra_handshake
+ try:
+ do_extra_handshake_(request)
+ except handshake.AbortedByUserException, e:
+ # Re-raise to tell the caller of this function to finish this
+ # connection without sending any error.
+ self._logger.debug('%s', util.get_stack_trace())
+ raise
+ except Exception, e:
+ util.prepend_message_to_exception(
+ '%s raised exception for %s: ' % (
+ _DO_EXTRA_HANDSHAKE_HANDLER_NAME,
+ request.ws_resource),
+ e)
+ raise handshake.HandshakeException(e, common.HTTP_STATUS_FORBIDDEN)
+
+ def transfer_data(self, request):
+ """Let a handler transfer_data with a WebSocket client.
+
+ Select a handler based on request.ws_resource and call its
+ web_socket_transfer_data function.
+
+ Args:
+ request: mod_python request.
+
+ Raises:
+ DispatchException: when handler was not found
+ AbortedByUserException: when user handler abort connection
+ """
+
+ # TODO(tyoshino): Terminate underlying TCP connection if possible.
+ try:
+ if mux.use_mux(request):
+ mux.start(request, self)
+ else:
+ handler_suite = self.get_handler_suite(request.ws_resource)
+ if handler_suite is None:
+ raise DispatchException('No handler for: %r' %
+ request.ws_resource)
+ transfer_data_ = handler_suite.transfer_data
+ transfer_data_(request)
+
+ if not request.server_terminated:
+ request.ws_stream.close_connection()
+ # Catch non-critical exceptions the handler didn't handle.
+ except handshake.AbortedByUserException, e:
+ self._logger.debug('%s', util.get_stack_trace())
+ raise
+ except msgutil.BadOperationException, e:
+ self._logger.debug('%s', e)
+ request.ws_stream.close_connection(
+ common.STATUS_INTERNAL_ENDPOINT_ERROR)
+ except msgutil.InvalidFrameException, e:
+ # InvalidFrameException must be caught before
+ # ConnectionTerminatedException that catches InvalidFrameException.
+ self._logger.debug('%s', e)
+ request.ws_stream.close_connection(common.STATUS_PROTOCOL_ERROR)
+ except msgutil.UnsupportedFrameException, e:
+ self._logger.debug('%s', e)
+ request.ws_stream.close_connection(common.STATUS_UNSUPPORTED_DATA)
+ except stream.InvalidUTF8Exception, e:
+ self._logger.debug('%s', e)
+ request.ws_stream.close_connection(
+ common.STATUS_INVALID_FRAME_PAYLOAD_DATA)
+ except msgutil.ConnectionTerminatedException, e:
+ self._logger.debug('%s', e)
+ except Exception, e:
+ # Any other exceptions are forwarded to the caller of this
+ # function.
+ util.prepend_message_to_exception(
+ '%s raised exception for %s: ' % (
+ _TRANSFER_DATA_HANDLER_NAME, request.ws_resource),
+ e)
+ raise
+
+ def passive_closing_handshake(self, request):
+ """Prepare code and reason for responding client initiated closing
+ handshake.
+ """
+
+ handler_suite = self.get_handler_suite(request.ws_resource)
+ if handler_suite is None:
+ return _default_passive_closing_handshake_handler(request)
+ return handler_suite.passive_closing_handshake(request)
+
+ def get_handler_suite(self, resource):
+ """Retrieves two handlers (one for extra handshake processing, and one
+ for data transfer) for the given request as a HandlerSuite object.
+ """
+
+ fragment = None
+ if '#' in resource:
+ resource, fragment = resource.split('#', 1)
+ if '?' in resource:
+ resource = resource.split('?', 1)[0]
+ handler_suite = self._handler_suite_map.get(resource)
+ if handler_suite and fragment:
+ raise DispatchException('Fragment identifiers MUST NOT be used on '
+ 'WebSocket URIs',
+ common.HTTP_STATUS_BAD_REQUEST)
+ return handler_suite
+
+ def _source_handler_files_in_dir(
+ self, root_dir, scan_dir, allow_handlers_outside_root_dir):
+ """Source all the handler source files in the scan_dir directory.
+
+ The resource path is determined relative to root_dir.
+ """
+
+ # We build a map from resource to handler code assuming that there's
+ # only one path from root_dir to scan_dir and it can be obtained by
+ # comparing realpath of them.
+
+ # Here we cannot use abspath. See
+ # https://bugs.webkit.org/show_bug.cgi?id=31603
+
+ convert = _create_path_to_resource_converter(root_dir)
+ scan_realpath = os.path.realpath(scan_dir)
+ root_realpath = os.path.realpath(root_dir)
+ for path in _enumerate_handler_file_paths(scan_realpath):
+ if (not allow_handlers_outside_root_dir and
+ (not os.path.realpath(path).startswith(root_realpath))):
+ self._logger.debug(
+ 'Canonical path of %s is not under root directory' %
+ path)
+ continue
+ try:
+ handler_suite = _source_handler_file(open(path).read())
+ except DispatchException, e:
+ self._source_warnings.append('%s: %s' % (path, e))
+ continue
+ resource = convert(path)
+ if resource is None:
+ self._logger.debug(
+ 'Path to resource conversion on %s failed' % path)
+ else:
+ self._handler_suite_map[convert(path)] = handler_suite
+
+
+# vi:sts=4 sw=4 et