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# -*- coding: utf-8 -*-
#
# transfer.py
#
# Copyright (C) 2012 Bro <bro.development@gmail.com>
#
# Deluge is free software.
#
# You may redistribute it and/or modify it under the terms of the
# GNU General Public License, as published by the Free Software
# Foundation; either version 3 of the License, or (at your option)
# any later version.
#
# deluge 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with deluge. If not, write to:
# The Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor
# Boston, MA 02110-1301, USA.
#
# In addition, as a special exception, the copyright holders give
# permission to link the code of portions of this program with the OpenSSL
# library.
# You must obey the GNU General Public License in all respects for all of
# the code used other than OpenSSL. If you modify file(s) with this
# exception, you may extend this exception to your version of the file(s),
# but you are not obligated to do so. If you do not wish to do so, delete
# this exception statement from your version. If you delete this exception
# statement from all source files in the program, then also delete it here.
#
#
try:
import rencode
except ImportError:
import deluge.rencode as rencode
import zlib
import struct
from twisted.internet.protocol import Protocol
from deluge.log import LOG as log
MESSAGE_HEADER_SIZE = 5
class DelugeTransferProtocol(Protocol):
"""
Data messages are transfered using very a simple protocol.
Data messages are transfered with a header containing
the length of the data to be transfered (payload).
"""
def __init__(self):
self._buffer = ""
self._message_length = 0
self._bytes_received = 0
self._bytes_sent = 0
def transfer_message(self, data):
"""
Transfer the data.
The data will be serialized and compressed before being sent.
First a header is sent - containing the length of the compressed payload
to come as a signed integer. After the header, the payload is transfered.
:param data: data to be transfered in a data structure serializable by rencode.
"""
compressed = zlib.compress(rencode.dumps(data))
size_data = len(compressed)
# Store length as a signed integer (using 4 bytes). "!" denotes network byte order.
payload_len = struct.pack("!i", size_data)
header = "D" + payload_len
self._bytes_sent += len(header) + len(compressed)
self.transport.write(header)
self.transport.write(compressed)
def dataReceived(self, data):
"""
This method is called whenever data is received.
:param data: a message as transfered by transfer_message, or a part of such
a messsage.
Global variables:
_buffer - contains the data received
_message_length - the length of the payload of the current message.
"""
self._buffer += data
self._bytes_received += len(data)
while len(self._buffer) >= MESSAGE_HEADER_SIZE:
if self._message_length == 0:
self._handle_new_message()
# We have a complete packet
if len(self._buffer) >= self._message_length:
self._handle_complete_message(self._buffer[:self._message_length])
# Remove message data from buffer
self._buffer = self._buffer[self._message_length:]
self._message_length = 0
else:
break
def _handle_new_message(self):
"""
Handle the start of a new message. This method is called only when the
beginning of the buffer contains data from a new message (i.e. the header).
"""
try:
# Read the first bytes of the message (MESSAGE_HEADER_SIZE bytes)
header = self._buffer[:MESSAGE_HEADER_SIZE]
payload_len = header[1:MESSAGE_HEADER_SIZE]
if header[0] != 'D':
raise Exception("Invalid header format. First byte is %d" % ord(header[0]))
# Extract the length stored as a signed integer (using 4 bytes)
self._message_length = struct.unpack("!i", payload_len)[0]
if self._message_length < 0:
raise Exception("Message length is negative: %d" % self._message_length)
# Remove the header from the buffer
self._buffer = self._buffer[MESSAGE_HEADER_SIZE:]
except Exception, e:
log.warn("Error occured when parsing message header: %s." % str(e))
log.warn("This version of Deluge cannot communicate with the sender of this data.")
self._message_length = 0
self._buffer = ""
def _handle_complete_message(self, data):
"""
Handles a complete message as it is transfered on the network.
:param data: a zlib compressed string encoded with rencode.
"""
try:
self.message_received(rencode.loads(zlib.decompress(data), decode_utf8=True))
except Exception, e:
log.warn("Failed to decompress (%d bytes) and load serialized data "\
"with rencode: %s" % (len(data), str(e)))
def get_bytes_recv(self):
"""
Returns the number of bytes received.
:returns: the number of bytes received
:rtype: int
"""
return self._bytes_received
def get_bytes_sent(self):
"""
Returns the number of bytes sent.
:returns: the number of bytes sent
:rtype: int
"""
return self._bytes_sent
def message_received(self, message):
"""Override this method to receive the complete message"""
pass
|
Deluge
