sugar-toolkit-gtk3/sugar/p2p/Stream.py

# Copyright (C) 2006, Red Hat, Inc.
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the
# Free Software Foundation, Inc., 59 Temple Place - Suite 330,
# Boston, MA 02111-1307, USA.

import xmlrpclib
import socket
import traceback
import random
import logging

import network
from MostlyReliablePipe import MostlyReliablePipe
from sugar.presence import Service

def is_multicast_address(address):
	"""Simple numerical check for whether an IP4 address
	is in the range for multicast addresses or not."""
	if not address:
		return False
	if address[3] != '.':
		return False
	first = int(float(address[:3]))
	if first >= 224 and first <= 239:
		return True
	return False

class Stream(object):
	def __init__(self, service):
		if not service.get_port():
			raise ValueError("service must have an address.")
		self._service = service
		self._reader_port = self._service.get_port()
		self._writer_port = self._reader_port
		self._address = self._service.get_address()
		self._callback = None

	def new_from_service(service, start_reader=True):
		if is_multicast_address(service.get_address()):
			return MulticastStream(service)
		else:
			return UnicastStream(service, start_reader)
	new_from_service = staticmethod(new_from_service)

	def set_data_listener(self, callback):
		self._callback = callback

	def _recv(self, address, data):
		if self._callback:
			self._callback(address, data)


class UnicastStreamWriter(object):
	def __init__(self, stream, service):
		# set up the writer
		self._service = service
		if not service.get_address():
			raise ValueError("service must have a valid address.")
		self._address = self._service.get_address()
		self._port = self._service.get_port()
		self._xmlrpc_addr = "http://%s:%d" % (self._address, self._port)
		self._writer = network.GlibServerProxy(self._xmlrpc_addr)

	def write(self, xmlrpc_data):
		"""Write some data to the default endpoint of this pipe on the remote server."""
		try:
			self._writer.message(None, None, xmlrpc_data)
			return True
		except (socket.error, xmlrpclib.Fault, xmlrpclib.ProtocolError):
			traceback.print_exc()
		return False

	def custom_request(self, method_name, request_cb, user_data, *args):
		"""Call a custom XML-RPC method on the remote server."""
		try:
			method = getattr(self._writer, method_name)
			method(request_cb, user_data, *args)
			return True
		except (socket.error, xmlrpclib.Fault, xmlrpclib.ProtocolError):
			traceback.print_exc()
		return False


class UnicastStream(Stream):
	def __init__(self, service, start_reader=True):
		"""Initializes the stream.  If the 'start_reader' argument is True,
		the stream will initialize and start a new stream reader, if it
		is False, no reader will be created and the caller must call the
		start_reader() method to start the stream reader and be able to
		receive any data from the stream."""
		Stream.__init__(self, service)
		if start_reader:
			self.start_reader()

	def start_reader(self):
		"""Start the stream's reader, which for UnicastStream objects is
		and XMLRPC server.  If there's a port conflict with some other
		service, the reader will try to find another port to use instead.
		Returns the port number used for the reader."""
		# Set up the reader
		self._reader = network.GlibXMLRPCServer(("", self._reader_port))
		self._reader.register_function(self._message, "message")

	def _message(self, message):
		"""Called by the XMLRPC server when network data arrives."""
		address = network.get_authinfo()
		self._recv(address, message)
		return True

	def register_reader_handler(self, handler, name):
		"""Register a custom message handler with the reader.  This call
		adds a custom XMLRPC method call with the name 'name' to the reader's
		XMLRPC server, which then calls the 'handler' argument back when
		a method call for it arrives over the network."""
		if name == "message":
			raise ValueError("Handler name 'message' is a reserved handler.")
		self._reader.register_function(handler, name)

	def new_writer(self, service):
		"""Return a new stream writer object."""
		return UnicastStreamWriter(self, service)


class MulticastStream(Stream):
	def __init__(self, service):
		Stream.__init__(self, service)
		self._service = service
		self._internal_start_reader()

	def start_reader(self):
		return self._reader_port

	def _internal_start_reader(self):
		logging.debug('Start multicast stream, address %s, port %d' % (self._address, self._reader_port))
		if not self._service.get_address():
			raise ValueError("service must have a valid address.")
		self._pipe = MostlyReliablePipe('', self._address, self._reader_port,
				self._recv_data_cb)
		self._pipe.start()

	def write(self, data):
		self._pipe.send(data)

	def _recv_data_cb(self, address, data, user_data=None):
		self._recv(address[0], data)

	def new_writer(self, service=None):
		return self