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Diffstat (limited to 'testing/mochitest/pywebsocket/mod_pywebsocket/dispatch.py')
| -rw-r--r-- | testing/mochitest/pywebsocket/mod_pywebsocket/dispatch.py | 393 |
1 files changed, 393 insertions, 0 deletions
diff --git a/testing/mochitest/pywebsocket/mod_pywebsocket/dispatch.py b/testing/mochitest/pywebsocket/mod_pywebsocket/dispatch.py new file mode 100644 index 000000000..96c91e0c9 --- /dev/null +++ b/testing/mochitest/pywebsocket/mod_pywebsocket/dispatch.py @@ -0,0 +1,393 @@ +# 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 |