SleekXMPP/sleekxmpp/xmlstream/xmlstream.py
2010-07-12 12:16:58 -04:00

495 lines
16 KiB
Python

"""
SleekXMPP: The Sleek XMPP Library
Copyright (C) 2010 Nathanael C. Fritz
This file is part of SleekXMPP.
See the file license.txt for copying permission.
"""
from __future__ import with_statement, unicode_literals
try:
import queue
except ImportError:
import Queue as queue
from . import statemachine
from . stanzabase import StanzaBase
from xml.etree import cElementTree
import logging
import random
import socket
import threading
import time
import traceback
from . import scheduler
HANDLER_THREADS = 1
ssl_support = True
#try:
import ssl
#except ImportError:
# ssl_support = False
import sys
if sys.version_info < (3, 0):
#monkey patch broken filesocket object
from . import filesocket
#socket._fileobject = filesocket.filesocket
class RestartStream(Exception):
pass
stanza_extensions = {}
RECONNECT_MAX_DELAY = 360
RECONNECT_QUIESCE_FACTOR = 1.6180339887498948 # Phi
RECONNECT_QUIESCE_JITTER = 0.11962656472 # molar Planck constant times c, joule meter/mole
DEFAULT_KEEPALIVE = 300 # send a single byte every 5 minutes
class XMLStream(object):
"A connection manager with XML events."
def __init__(self, socket=None, host='', port=5222, escape_quotes=False):
global ssl_support
self.ssl_support = ssl_support
self.escape_quotes = escape_quotes
self.state = statemachine.StateMachine(('disconnected','connected'))
self.should_reconnect = True
self.setSocket(socket)
self.address = (host, int(port))
self.__thread = {}
self.__root_stanza = []
self.__stanza = {}
self.__stanza_extension = {}
self.__handlers = []
self.filesocket = None
self.use_ssl = False
self.ca_certs=None
self.keep_alive = DEFAULT_KEEPALIVE
self._last_sent_time = time.time()
self.stream_header = "<stream>"
self.stream_footer = "</stream>"
self.eventqueue = queue.Queue()
self.sendqueue = queue.PriorityQueue()
self.scheduler = scheduler.Scheduler(self.eventqueue)
self.namespace_map = {}
# booleans are not volatile in Python and changes
# do not seem to be detected easily between threads.
self.quit = threading.Event()
def setSocket(self, socket):
"Set the socket"
self.socket = socket
if socket is not None:
with self.state.transition_ctx('disconnected','connected') as locked:
if not locked: raise Exception('Already connected')
# ElementTree.iterparse requires a file. 0 buffer files have to be binary
self.filesocket = socket.makefile('rb', 0)
def setFileSocket(self, filesocket):
self.filesocket = filesocket
def connect(self, host='', port=5222, use_ssl=None):
"Establish a socket connection to the given XMPP server."
if not self.state.transition('disconnected','connected',
func=self.connectTCP, args=[host, port, use_ssl] ):
if self.state['connected']: logging.debug('Already connected')
else: logging.warning("Connection failed" )
return False
logging.debug('Connection complete.')
return True
# TODO currently a caller can't distinguish between "connection failed" and
# "we're already trying to connect from another thread"
def connectTCP(self, host='', port=5222, use_ssl=None, reattempt=True):
"Connect and create socket"
# Note that this is thread-safe by merit of being called solely from connect() which
# holds the state lock.
delay = 1.0 # reconnection delay
while not self.quit.is_set():
logging.debug('connecting....')
try:
if host and port:
self.address = (host, int(port))
if use_ssl is not None:
self.use_ssl = use_ssl
if sys.version_info < (3, 0):
self.socket = filesocket.Socket26(socket.AF_INET, socket.SOCK_STREAM)
else:
self.socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.socket.settimeout(None)
if self.use_ssl and self.ssl_support:
logging.debug("Socket Wrapped for SSL")
cert_policy = ssl.CERT_NONE if self.ca_certs is None else ssl.CERT_REQUIRED
self.socket = ssl.wrap_socket(self.socket,
ca_certs=self.ca_certs, cert_reqs=cert_policy)
self.socket.connect(self.address)
self.filesocket = self.socket.makefile('rb', 0)
return True
except socket.error as serr:
logging.exception("Socket Error #%s: %s", serr.errno, serr.strerror)
if not reattempt: return False
except:
logging.exception("Connection error")
if not reattempt: return False
# quiesce if rconnection fails:
# This algorithm based loosely on Twisted internet.protocol
# http://twistedmatrix.com/trac/browser/trunk/twisted/internet/protocol.py#L310
delay = min(delay * RECONNECT_QUIESCE_FACTOR, RECONNECT_MAX_DELAY)
delay = random.normalvariate(delay, delay * RECONNECT_QUIESCE_JITTER)
logging.debug('Waiting %.3fs until next reconnect attempt...', delay)
time.sleep(delay)
def connectUnix(self, filepath):
"Connect to Unix file and create socket"
def startTLS(self):
"Handshakes for TLS"
# TODO since this is not part of the 'connectTCP' method, it does not quiesce if
# The TLS negotiation throws an SSLError. It really should. Worse yet, some
# errors might be considered fatal (like certificate verification failure) in which
# case, should we even attempt to re-connect at all?
if self.ssl_support:
logging.info("Negotiating TLS")
# self.realsocket = self.socket # NOT USED
cert_policy = ssl.CERT_NONE if self.ca_certs is None else ssl.CERT_REQUIRED
self.socket = ssl.wrap_socket(self.socket,
ssl_version=ssl.PROTOCOL_TLSv1,
do_handshake_on_connect=False,
cert_reqs=cert_policy,
ca_certs=self.ca_certs)
self.socket.do_handshake()
if sys.version_info < (3,0):
from . filesocket import filesocket
self.filesocket = filesocket(self.socket)
else:
self.filesocket = self.socket.makefile('rb', 0)
logging.debug("TLS negotitation successful")
return True
else:
logging.warning("Tried to enable TLS, but ssl module not found.")
return False
raise RestartStream()
def process(self, threaded=True):
self.quit.clear()
self.scheduler.process(threaded=True)
for t in range(0, HANDLER_THREADS):
th = threading.Thread(name='eventhandle%s' % t, target=self._eventRunner)
th.setDaemon(True)
self.__thread['eventhandle%s' % t] = th
th.start()
th = threading.Thread(name='sendthread', target=self._sendThread)
th.setDaemon(True)
self.__thread['sendthread'] = th
th.start()
if threaded:
th = threading.Thread(name='process', target=self._process)
th.setDaemon(True)
self.__thread['process'] = th
th.start()
else:
self._process()
def schedule(self, name, seconds, callback, args=None, kwargs=None, repeat=False):
self.scheduler.add(name, seconds, callback, args, kwargs, repeat, qpointer=self.eventqueue)
def _process(self):
"Start processing the socket."
logging.debug('Process thread starting...')
while not self.quit.is_set():
if not self.state.ensure('connected',wait=2, block_on_transition=True): continue
try:
self.sendRaw(self.stream_header, priority=0, init=True)
self.__readXML() # this loops until the stream is terminated.
except socket.timeout:
# TODO currently this will re-send a stream header if this exception occurs.
# I don't think that's intended behavior.
logging.warn('socket rcv timeout')
except RestartStream:
logging.debug("Restarting stream...")
continue # DON'T re-initialize the stream -- this exception is sent
# specifically when we've initialized TLS and need to re-send the <stream> header.
except (KeyboardInterrupt, SystemExit):
logging.debug("System interrupt detected")
self.shutdown()
self.eventqueue.put(('quit', None, None))
except:
logging.exception('Unexpected error in RCV thread')
# if the RCV socket is terminated for whatever reason (e.g. we reach this point of
# code,) our only sane choice of action is an attempt to re-establish the connection.
reconnect = (self.should_reconnect and not self.quit.is_set())
self.disconnect(reconnect=reconnect, error=True)
logging.debug('Quitting Process thread')
def __readXML(self):
"Parses the incoming stream, adding to xmlin queue as it goes"
#build cElementTree object from expat was we go
#self.filesocket = self.socket.makefile('rb', 0)
#print self.filesocket.read(1024) #self.filesocket._sock.recv(1024)
edepth = 0
root = None
for (event, xmlobj) in cElementTree.iterparse(self.filesocket, (b'end', b'start')):
if edepth == 0: # and xmlobj.tag.split('}', 1)[-1] == self.basetag:
if event == b'start':
root = xmlobj
logging.debug('handling start stream')
self.start_stream_handler(root)
if event == b'end':
edepth += -1
if edepth == 0 and event == b'end':
logging.warn("Premature EOF from read socket; Ending readXML loop")
# this is a premature EOF as far as I can tell; raise an exception so the stream get closed and re-established cleanly.
return False
elif edepth == 1:
#self.xmlin.put(xmlobj)
self.__spawnEvent(xmlobj)
if root: root.clear()
if event == b'start':
edepth += 1
logging.warn("Exiting readXML loop")
# TODO under what conditions will this _ever_ occur?
return False
def _sendThread(self):
logging.debug('send thread starting...')
while not self.quit.is_set():
if not self.state.ensure('connected',wait=2, block_on_transition=True): continue
data = None
try:
data = self.sendqueue.get(True,5)[1]
logging.debug("SEND: %s" % data)
self.socket.sendall(data.encode('utf-8'))
self._last_sent_time = time.time()
except queue.Empty: # send keep-alive if necessary
now = time.time()
if self._last_sent_time + self.keep_alive < now:
self.socket.sendall(' ')
self._last_sent_time = time.time()
except socket.timeout:
# this is to prevent a thread blocked indefinitely
logging.debug('timeout sending packet data')
except:
logging.warning("Failed to send %s" % data)
logging.exception("Socket error in SEND thread")
# TODO it's somewhat unsafe for the sender thread to assume it can just
# re-intitialize the connection, since the receiver thread could be doing
# the same thing concurrently. Oops! The safer option would be to throw
# some sort of event that could be handled by a common thread or the reader
# thread to perform reconnect and then re-initialize the handler threads as well.
reconnect = (self.should_reconnect and not self.quit.is_set())
self.disconnect(reconnect=reconnect, error=True)
def sendRaw( self, data, priority=5, init=False ):
if not self.state.ensure('connected'): return False
self.sendqueue.put((priority, data))
return True
def disconnect(self, reconnect=False, error=False):
with self.state.transition_ctx('connected','disconnected') as locked:
if not locked:
logging.warning("Already disconnected.")
return
logging.debug("Disconnecting...")
# don't send a footer on error; if the stream is already closed,
# this won't get sent until the stream is re-initialized!
if not error: self.sendRaw(self.stream_footer,init=True) #send end of stream
try:
# self.socket.shutdown(socket.SHUT_RDWR)
self.socket.close()
except socket.error as (errno,strerror):
logging.exception("Error while disconnecting. Socket Error #%s: %s" % (errno, strerror))
try:
self.filesocket.close()
except socket.error as (errno,strerror):
logging.exception("Error closing filesocket.")
if reconnect: self.connect()
def shutdown(self):
'''
Disconnects and shuts down all event threads.
'''
self.run = False
self.scheduler.run = False
self.disconnect()
def incoming_filter(self, xmlobj):
return xmlobj
def __spawnEvent(self, xmlobj):
"watching xmlOut and processes handlers"
if logging.getLogger().isEnabledFor(logging.DEBUG):
logging.debug("RECV: %s" % cElementTree.tostring(xmlobj))
#convert XML into Stanza
xmlobj = self.incoming_filter(xmlobj)
stanza = None
for stanza_class in self.__root_stanza:
if xmlobj.tag == "{%s}%s" % (self.default_ns, stanza_class.name):
#if self.__root_stanza[stanza_class].match(xmlobj):
stanza = stanza_class(self, xmlobj)
break
if stanza is None:
stanza = StanzaBase(self, xmlobj)
unhandled = True
# TODO inefficient linear search; performance might be improved by hashtable lookup
for handler in self.__handlers:
if handler.match(stanza):
# logging.debug('matched stanza to handler %s', handler.name)
handler.prerun(stanza)
self.eventqueue.put(('stanza', handler, stanza))
if handler.checkDelete():
# logging.debug('deleting callback %s', handler.name)
self.__handlers.pop(self.__handlers.index(handler))
unhandled = False
if unhandled:
stanza.unhandled()
#loop through handlers and test match
#spawn threads as necessary, call handlers, sending Stanza
def _eventRunner(self):
logging.debug("Loading event runner")
while not self.quit.is_set():
try:
event = self.eventqueue.get(True, timeout=5)
except queue.Empty:
# logging.debug('Nothing on event queue')
event = None
if event is not None:
etype = event[0]
handler = event[1]
args = event[2:]
#etype, handler, *args = event #python 3.x way
if etype == 'stanza':
try:
handler.run(args[0])
except Exception as e:
logging.exception("Exception in event handler")
args[0].exception(e)
elif etype == 'sched':
try:
#handler(*args[0])
handler.run(*args)
except:
logging.error(traceback.format_exc())
elif etype == 'quit':
logging.debug("Quitting eventRunner thread")
return False
def registerHandler(self, handler, before=None, after=None):
"Add handler with matcher class and parameters."
self.__handlers.append(handler)
def removeHandler(self, name):
"Removes the handler."
idx = 0
for handler in self.__handlers:
if handler.name == name:
self.__handlers.pop(idx)
return
idx += 1
def registerStanza(self, stanza_class):
"Adds stanza. If root stanzas build stanzas sent in events while non-root stanzas build substanza objects."
self.__root_stanza.append(stanza_class)
def registerStanzaExtension(self, stanza_class, stanza_extension):
if stanza_class not in stanza_extensions:
stanza_extensions[stanza_class] = [stanza_extension]
else:
stanza_extensions[stanza_class].append(stanza_extension)
def removeStanza(self, stanza_class, root=False):
"Removes the stanza's registration."
if root:
del self.__root_stanza[stanza_class]
else:
del self.__stanza[stanza_class]
def removeStanzaExtension(self, stanza_class, stanza_extension):
stanza_extension[stanza_class].pop(stanza_extension)
def tostring(self, xml, xmlns='', stringbuffer=''):
newoutput = [stringbuffer]
#TODO respect ET mapped namespaces
itag = xml.tag.split('}', 1)[-1]
if '}' in xml.tag:
ixmlns = xml.tag.split('}', 1)[0][1:]
else:
ixmlns = ''
nsbuffer = ''
if xmlns != ixmlns and ixmlns != '':
if ixmlns in self.namespace_map:
if self.namespace_map[ixmlns] != '':
itag = "%s:%s" % (self.namespace_map[ixmlns], itag)
else:
nsbuffer = """ xmlns="%s\"""" % ixmlns
newoutput.append("<%s" % itag)
newoutput.append(nsbuffer)
for attrib in xml.attrib:
newoutput.append(""" %s="%s\"""" % (attrib, self.xmlesc(xml.attrib[attrib])))
if len(xml) or xml.text or xml.tail:
newoutput.append(">")
if xml.text:
newoutput.append(self.xmlesc(xml.text))
if len(xml):
for child in xml.getchildren():
newoutput.append(self.tostring(child, ixmlns))
newoutput.append("</%s>" % (itag, ))
if xml.tail:
newoutput.append(self.xmlesc(xml.tail))
elif xml.text:
newoutput.append(">%s</%s>" % (self.xmlesc(xml.text), itag))
else:
newoutput.append(" />")
return ''.join(newoutput)
def xmlesc(self, text):
text = list(text)
cc = 0
matches = ('&', '<', '"', '>', "'")
for c in text:
if c in matches:
if c == '&':
text[cc] = '&amp;'
elif c == '<':
text[cc] = '&lt;'
elif c == '>':
text[cc] = '&gt;'
elif c == "'":
text[cc] = '&apos;'
elif self.escape_quotes:
text[cc] = '&quot;'
cc += 1
return ''.join(text)
def start_stream_handler(self, xml):
"""Meant to be overridden"""
logging.warn("No start stream handler has been implemented.")