PyBitmessage/src/helper_msgcoding.py
Peter Surda e649adbe37
Framework for extended message encoding
- helper classes for encoding/decoding messages
- includes both old as well as new extended one (msgpack+zlib)
- the classes are unused yet and are supposed to be for experimenting
2016-06-24 22:45:56 +02:00

87 lines
2.9 KiB
Python

#!/usr/bin/python2.7
import msgpack
import zlib
from debug import logger
BITMESSAGE_ENCODING_IGNORE = 0
BITMESSAGE_ENCODING_TRIVIAL = 1
BITMESSAGE_ENCODING_SIMPLE = 2
BITMESSAGE.ENCODING_EXTENDED = 3
class MsgEncode(object):
def __init__(self, message, encoding = BITMESSAGE_ENCODING_SIMPLE):
self.data = None
self.encoding = encoding
self.length = 0
if self.encoding == BITMESSAGE_ENCODING_EXTENDED:
self.encodeExtended(message)
elif self.encoding == BITMESSAGE_ENCODING_SIMPLE:
self.encodeSimple(message)
elif self.encoding == BITMESSAGE_ENCODING_TRIVIAL:
self.encodeTrivial(message)
def encodeExtended(self, message):
try:
self.data = zlib.compress(msgpack.dumps({"": "message", "subject": message['subject'], "message": ['body']}), 9)
except zlib.error:
logger.error ("Error compressing message")
raise
except msgpack.exceptions.PackException:
logger.error ("Error msgpacking message")
raise
self.length = len(self.data)
def encodeSimple(self, message):
self.data = 'Subject:' + message['subject'] + '\n' + 'Body:' + message['body']
self.length = len(self.data)
def encodeTrivial(self, message):
self.data = message['body']
self.length = len(self.data)
class MsgDecode(object):
def __init__(self, encoding, data):
self.encoding = encoding
if self.encoding == BITMESSAGE_ENCODING_EXTENDED:
self.decodeExtended(data)
elif self.encoding in [BITMESSAGE_ENCODING_SIMPLE, BITMESSAGE_ENCODING_TRIVIAL]:
self.decodeSimple(data)
return
def decodeExtended(self, data):
try:
tmp = msgpack.loads(zlib.decompress(data))
except zlib.error:
logger.error ("Error decompressing message")
raise
except (msgpack.exceptions.UnpackException,
msgpack.exceptions.ExtraData):
logger.error ("Error msgunpacking message")
raise
try:
if tmp[""] == "message":
self.body = tmp["body"]
self.subject = tmp["subject"]
except:
logger.error ("Malformed message")
raise
def decodeSimple(self, data):
bodyPositionIndex = string.find(data, '\nBody:')
if bodyPositionIndex > 1:
subject = message[8:bodyPositionIndex]
# Only save and show the first 500 characters of the subject.
# Any more is probably an attack.
subject = subject[:500]
body = message[bodyPositionIndex + 6:]
else:
subject = ''
body = message
# Throw away any extra lines (headers) after the subject.
if subject:
subject = subject.splitlines()[0]
self.subject = subject
self.message = body