slixmpp/sleekxmpp/xmlstream/xmlstream.py

819 lines
31 KiB
Python

"""
SleekXMPP: The Sleek XMPP Library
Copyright (C) 2010 Nathanael C. Fritz
This file is part of SleekXMPP.
See the file LICENSE for copying permission.
"""
from __future__ import with_statement, unicode_literals
import copy
import logging
import socket
import ssl
import sys
import threading
import time
import types
try:
import queue
except ImportError:
import Queue as queue
from sleekxmpp.xmlstream import StateMachine, Scheduler, tostring
from sleekxmpp.xmlstream.stanzabase import StanzaBase, ET
# In Python 2.x, file socket objects are broken. A patched socket
# wrapper is provided for this case in filesocket.py.
if sys.version_info < (3, 0):
from sleekxmpp.xmlstream.filesocket import FileSocket, Socket26
# The time in seconds to wait before timing out waiting for response stanzas.
RESPONSE_TIMEOUT = 10
# The number of threads to use to handle XML stream events. This is not the
# same as the number of custom event handling threads. HANDLER_THREADS must
# be at least 1.
HANDLER_THREADS = 1
# Flag indicating if the SSL library is available for use.
SSL_SUPPORT = True
class RestartStream(Exception):
"""
Exception to restart stream processing, including
resending the stream header.
"""
class XMLStream(object):
"""
An XML stream connection manager and event dispatcher.
The XMLStream class abstracts away the issues of establishing a
connection with a server and sending and receiving XML "stanzas".
A stanza is a complete XML element that is a direct child of a root
document element. Two streams are used, one for each communication
direction, over the same socket. Once the connection is closed, both
streams should be complete and valid XML documents.
Three types of events are provided to manage the stream:
Stream -- Triggered based on received stanzas, similar in concept
to events in a SAX XML parser.
Custom -- Triggered manually.
Scheduled -- Triggered based on time delays.
Typically, stanzas are first processed by a stream event handler which
will then trigger custom events to continue further processing,
especially since custom event handlers may run in individual threads.
Attributes:
address -- The hostname and port of the server.
default_ns -- The default XML namespace that will be applied
to all non-namespaced stanzas.
event_queue -- A queue of stream, custom, and scheduled
events to be processed.
filesocket -- A filesocket created from the main connection socket.
Required for ElementTree.iterparse.
namespace_map -- Optional mapping of namespaces to namespace prefixes.
scheduler -- A scheduler object for triggering events
after a given period of time.
send_queue -- A queue of stanzas to be sent on the stream.
socket -- The connection to the server.
ssl_support -- Indicates if a SSL library is available for use.
state -- A state machine for managing the stream's
connection state.
stream_footer -- The start tag and any attributes for the stream's
root element.
stream_header -- The closing tag of the stream's root element.
use_ssl -- Flag indicating if SSL should be used.
use_tls -- Flag indicating if TLS should be used.
Methods:
add_event_handler -- Add a handler for a custom event.
add_handler -- Shortcut method for registerHandler.
connect -- Connect to the given server.
del_event_handler -- Remove a handler for a custom event.
disconnect -- Disconnect from the server and terminate
processing.
event -- Trigger a custom event.
get_id -- Return the current stream ID.
incoming_filter -- Optionally filter stanzas before processing.
new_id -- Generate a new, unique ID value.
process -- Read XML stanzas from the stream and apply
matching stream handlers.
reconnect -- Reestablish a connection to the server.
register_handler -- Add a handler for a stream event.
register_stanza -- Add a new stanza object type that may appear
as a direct child of the stream's root.
remove_handler -- Remove a stream handler.
remove_stanza -- Remove a stanza object type.
schedule -- Schedule an event handler to execute after a
given delay.
send -- Send a stanza object on the stream.
send_raw -- Send a raw string on the stream.
send_xml -- Send an XML string on the stream.
set_socket -- Set the stream's socket and generate a new
filesocket.
start_stream_handler -- Perform any stream initialization such
as handshakes.
start_tls -- Establish a TLS connection and restart
the stream.
"""
def __init__(self, socket=None, host='', port=0):
"""
Establish a new XML stream.
Arguments:
socket -- Use an existing socket for the stream.
Defaults to None to generate a new socket.
host -- The name of the target server.
Defaults to the empty string.
port -- The port to use for the connection.
Defaults to 0.
"""
# To comply with PEP8, method names now use underscores.
# Deprecated method names are re-mapped for backwards compatibility.
self.startTLS = self.start_tls
self.registerStanza = self.register_stanza
self.removeStanza = self.remove_stanza
self.registerHandler = self.register_handler
self.removeHandler = self.remove_handler
self.setSocket = self.set_socket
self.sendRaw = self.send_raw
self.getId = self.get_id
self.getNewId = self.new_id
self.sendXML = self.send_xml
self.ssl_support = SSL_SUPPORT
# TODO: Integrate the new state machine.
self.state = StateMachine()
self.state.addStates({'connected': False,
'is client': False,
'ssl': False,
'tls': False,
'reconnect': True,
'processing': False,
'disconnecting': False})
self.address = (host, int(port))
self.filesocket = None
self.set_socket(socket)
self.use_ssl = False
self.use_tls = False
self.default_ns = ''
self.stream_header = "<stream>"
self.stream_footer = "</stream>"
self.event_queue = queue.Queue()
self.send_queue = queue.Queue()
self.scheduler = Scheduler(self.event_queue)
self.namespace_map = {}
self.__thread = {}
self.__root_stanza = []
self.__handlers = []
self.__event_handlers = {}
self.__event_handlers_lock = threading.Lock()
self._id = 0
self._id_lock = threading.Lock()
self.run = True
def new_id(self):
"""
Generate and return a new stream ID in hexadecimal form.
Many stanzas, handlers, or matchers may require unique
ID values. Using this method ensures that all new ID values
are unique in this stream.
"""
with self._id_lock:
self._id += 1
return self.get_id()
def get_id(self):
"""
Return the current unique stream ID in hexadecimal form.
"""
return "%X" % self._id
def connect(self, host='', port=0, use_ssl=False,
use_tls=True, reattempt=True):
"""
Create a new socket and connect to the server.
Setting reattempt to True will cause connection attempts to be made
every second until a successful connection is established.
Arguments:
host -- The name of the desired server for the connection.
port -- Port to connect to on the server.
use_ssl -- Flag indicating if SSL should be used.
use_tls -- Flag indicating if TLS should be used.
reattempt -- Flag indicating if the socket should reconnect
after disconnections.
"""
if host and port:
self.address = (host, int(port))
# Respect previous SSL and TLS usage directives.
if use_ssl is not None:
self.use_ssl = use_ssl
if use_tls is not None:
self.use_tls = use_tls
self.state.set('is client', True)
# Repeatedly attempt to connect until a successful connection
# is established.
while reattempt and not self.state['connected']:
if sys.version_info < (3, 0):
self.socket = 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")
self.socket = ssl.wrap_socket(self.socket)
try:
self.socket.connect(self.address)
self.set_socket(self.socket)
self.state.set('connected', True)
return True
except socket.error as serr:
error_msg = "Could not connect. Socket Error #%s: %s"
logging.error(error_msg % (serr.errno, serr.strerror))
time.sleep(1)
def disconnect(self, reconnect=False):
"""
Terminate processing and close the XML streams.
Optionally, the connection may be reconnected and
resume processing afterwards.
Arguments:
reconnect -- Flag indicating if the connection
and processing should be restarted.
Defaults to False.
"""
self.event("disconnected")
self.state.set('reconnect', reconnect)
if self.state['disconnecting']:
return
if not self.state['reconnect']:
logging.debug("Disconnecting...")
self.state.set('disconnecting', True)
self.run = False
self.scheduler.run = False
if self.state['connected']:
# Send the end of stream marker.
self.send_raw(self.stream_footer)
# Wait for confirmation that the stream was
# closed in the other direction.
time.sleep(1)
try:
self.socket.close()
self.filesocket.close()
self.socket.shutdown(socket.SHUT_RDWR)
except socket.error as serr:
pass
def reconnect(self):
"""
Reset the stream's state and reconnect to the server.
"""
logging.info("Reconnecting")
self.event("disconnected")
self.state.set('tls', False)
self.state.set('ssl', False)
time.sleep(1)
self.connect()
def set_socket(self, socket):
"""
Set the socket to use for the stream.
The filesocket will be recreated as well.
Arguments:
socket -- The new socket to use.
"""
self.socket = socket
if socket is not None:
# ElementTree.iterparse requires a file.
# 0 buffer files have to be binary.
# Use the correct fileobject type based on the Python
# version to work around a broken implementation in
# Python 2.x.
if sys.version_info < (3, 0):
self.filesocket = FileSocket(self.socket)
else:
self.filesocket = self.socket.makefile('rb', 0)
self.state.set('connected', True)
def start_tls(self):
"""
Perform handshakes for TLS.
If the handshake is successful, the XML stream will need
to be restarted.
"""
if self.ssl_support:
logging.info("Negotiating TLS")
self.socket = ssl.wrap_socket(self.socket,
ssl_version=ssl.PROTOCOL_TLSv1,
do_handshake_on_connect=False)
self.socket.do_handshake()
self.set_socket(self.socket)
return True
else:
logging.warning("Tried to enable TLS, but ssl module not found.")
return False
def start_stream_handler(self, xml):
"""
Perform any initialization actions, such as handshakes, once the
stream header has been sent.
Meant to be overridden.
"""
pass
def register_stanza(self, stanza_class):
"""
Add a stanza object class as a known root stanza. A root stanza is
one that appears as a direct child of the stream's root element.
Stanzas that appear as substanzas of a root stanza do not need to
be registered here. That is done using registerStanzaPlugin() from
sleekxmpp.xmlstream.stanzabase.
Stanzas that are not registered will not be converted into
stanza objects, but may still be processed using handlers and
matchers.
Arguments:
stanza_class -- The top-level stanza object's class.
"""
self.__root_stanza.append(stanza_class)
def remove_stanza(self, stanza_class):
"""
Remove a stanza from being a known root stanza. A root stanza is
one that appears as a direct child of the stream's root element.
Stanzas that are not registered will not be converted into
stanza objects, but may still be processed using handlers and
matchers.
"""
del self.__root_stanza[stanza_class]
def add_handler(self, mask, pointer, name=None, disposable=False,
threaded=False, filter=False, instream=False):
"""
A shortcut method for registering a handler using XML masks.
Arguments:
mask -- An XML snippet matching the structure of the
stanzas that will be passed to this handler.
pointer -- The handler function itself.
name -- A unique name for the handler. A name will
be generated if one is not provided.
disposable -- Indicates if the handler should be discarded
after one use.
threaded -- Deprecated. Remains for backwards compatibility.
filter -- Deprecated. Remains for backwards compatibility.
instream -- Indicates if the handler should execute during
stream processing and not during normal event
processing.
"""
# To prevent circular dependencies, we must load the matcher
# and handler classes here.
from sleekxmpp.xmlstream.matcher import MatchXMLMask
from sleekxmpp.xmlstream.handler import XMLCallback
if name is None:
name = 'add_handler_%s' % self.getNewId()
self.registerHandler(XMLCallback(name, MatchXMLMask(mask), pointer,
once=disposable, instream=instream))
def register_handler(self, handler, before=None, after=None):
"""
Add a stream event handler that will be executed when a matching
stanza is received.
Arguments:
handler -- The handler object to execute.
"""
if handler.stream is None:
self.__handlers.append(handler)
handler.stream = self
def remove_handler(self, name):
"""
Remove any stream event handlers with the given name.
Arguments:
name -- The name of the handler.
"""
idx = 0
for handler in self.__handlers:
if handler.name == name:
self.__handlers.pop(idx)
return True
idx += 1
return False
def add_event_handler(self, name, pointer,
threaded=False, disposable=False):
"""
Add a custom event handler that will be executed whenever
its event is manually triggered.
Arguments:
name -- The name of the event that will trigger
this handler.
pointer -- The function to execute.
threaded -- If set to True, the handler will execute
in its own thread. Defaults to False.
disposable -- If set to True, the handler will be
discarded after one use. Defaults to False.
"""
if not name in self.__event_handlers:
self.__event_handlers[name] = []
self.__event_handlers[name].append((pointer, threaded, disposable))
def del_event_handler(self, name, pointer):
"""
Remove a function as a handler for an event.
Arguments:
name -- The name of the event.
pointer -- The function to remove as a handler.
"""
if not name in self.__event_handlers:
return
# Need to keep handlers that do not use
# the given function pointer
def filter_pointers(handler):
return handler[0] != pointer
self.__event_handlers[name] = filter(filter_pointers,
self.__event_handlers[name])
def event(self, name, data={}):
"""
Manually trigger a custom event.
Arguments:
name -- The name of the event to trigger.
data -- Data that will be passed to each event handler.
Defaults to an empty dictionary.
"""
for handler in self.__event_handlers.get(name, []):
self.event_queue.put(('event', handler, copy.copy(data)))
if handler[2]:
# If the handler is disposable, we will go ahead and
# remove it now instead of waiting for it to be
# processed in the queue.
with self.__event_handlers_lock:
handler_index = self.__event_handlers[name].index(handler)
try:
self.__event_handlers[name].pop(handler_index)
except:
pass
def schedule(self, name, seconds, callback, args=None,
kwargs=None, repeat=False):
"""
Schedule a callback function to execute after a given delay.
Arguments:
name -- A unique name for the scheduled callback.
seconds -- The time in seconds to wait before executing.
callback -- A pointer to the function to execute.
args -- A tuple of arguments to pass to the function.
kwargs -- A dictionary of keyword arguments to pass to
the function.
repeat -- Flag indicating if the scheduled event should
be reset and repeat after executing.
"""
self.scheduler.add(name, seconds, callback, args, kwargs,
repeat, qpointer=self.event_queue)
def incoming_filter(self, xml):
"""
Filter incoming XML objects before they are processed.
Possible uses include remapping namespaces, or correcting elements
from sources with incorrect behavior.
Meant to be overridden.
"""
return xml
def send(self, data, mask=None, timeout=RESPONSE_TIMEOUT):
"""
A wrapper for send_raw for sending stanza objects.
May optionally block until an expected response is received.
Arguments:
data -- The stanza object to send on the stream.
mask -- Deprecated. An XML snippet matching the structure
of the expected response. Execution will block
in this thread until the response is received
or a timeout occurs.
timeout -- Time in seconds to wait for a response before
continuing. Defaults to RESPONSE_TIMEOUT.
"""
if hasattr(mask, 'xml'):
mask = mask.xml
data = str(data)
if mask is not None:
logging.warning("Use of send mask waiters is deprecated.")
wait_for = Waiter("SendWait_%s" % self.new_id(),
MatchXMLMask(mask))
self.register_handler(wait_for)
self.send_raw(data)
if mask is not None:
return wait_for.wait(timeout)
def send_raw(self, data):
"""
Send raw data across the stream.
Arguments:
data -- Any string value.
"""
self.send_queue.put(data)
return True
def send_xml(self, data, mask=None, timeout=RESPONSE_TIMEOUT):
"""
Send an XML object on the stream, and optionally wait
for a response.
Arguments:
data -- The XML object to send on the stream.
mask -- Deprecated. An XML snippet matching the structure
of the expected response. Execution will block
in this thread until the response is received
or a timeout occurs.
timeout -- Time in seconds to wait for a response before
continuing. Defaults to RESPONSE_TIMEOUT.
"""
return self.send(tostring(data), mask, timeout)
def process(self, threaded=True):
"""
Initialize the XML streams and begin processing events.
The number of threads used for processing stream events is determined
by HANDLER_THREADS.
Arguments:
threaded -- If threaded=True then event dispatcher will run
in a separate thread, allowing for the stream to be
used in the background for another application.
Defaults to True.
Event handlers and the send queue will be threaded
regardless of this parameter's value.
"""
self.scheduler.process(threaded=True)
def start_thread(name, target):
self.__thread[name] = threading.Thread(name=name, target=target)
self.__thread[name].start()
for t in range(0, HANDLER_THREADS):
logging.debug("Starting HANDLER THREAD")
start_thread('stream_event_handler_%s' % t, self._event_runner)
start_thread('send_thread', self._send_thread)
if threaded:
# Run the XML stream in the background for another application.
start_thread('process', self._process)
else:
self._process()
def _process(self):
"""
Start processing the XML streams.
Processing will continue after any recoverable errors
if reconnections are allowed.
"""
firstrun = True
# The body of this loop will only execute once per connection.
# Additional passes will be made only if an error occurs and
# reconnecting is permitted.
while self.run and (firstrun or self.state['reconnect']):
self.state.set('processing', True)
firstrun = False
try:
if self.state['is client']:
self.send_raw(self.stream_header)
# The call to self.__read_xml will block and prevent
# the body of the loop from running until a disconnect
# occurs. After any reconnection, the stream header will
# be resent and processing will resume.
while self.run and self.__read_xml():
# Ensure the stream header is sent for any
# new connections.
if self.state['is client']:
self.send_raw(self.stream_header)
except KeyboardInterrupt:
logging.debug("Keyboard Escape Detected")
self.state.set('processing', False)
self.state.set('reconnect', False)
self.disconnect()
self.run = False
self.scheduler.run = False
self.event_queue.put(('quit', None, None))
return
except SystemExit:
self.event_queue.put(('quit', None, None))
return
except socket.error:
if not self.state.reconnect:
return
self.state.set('processing', False)
logging.exception('Socket Error')
self.disconnect(reconnect=True)
except:
if not self.state.reconnect:
return
self.state.set('processing', False)
logging.exception('Connection error. Reconnecting.')
self.disconnect(reconnect=True)
if self.state['reconnect']:
self.reconnect()
self.state.set('processing', False)
self.event_queue.put(('quit', None, None))
def __read_xml(self):
"""
Parse the incoming XML stream, raising stream events for
each received stanza.
"""
depth = 0
root = None
for (event, xml) in ET.iterparse(self.filesocket, (b'end', b'start')):
if event == b'start':
if depth == 0:
# We have received the start of the root element.
root = xml
# Perform any stream initialization actions, such
# as handshakes.
self.start_stream_handler(root)
depth += 1
if event == b'end':
depth -= 1
if depth == 0:
# The stream's root element has closed,
# terminating the stream.
self.disconnect(reconnect=self.state['reconnect'])
logging.debug("Ending read XML loop")
return False
elif depth == 1:
# We only raise events for stanzas that are direct
# children of the root element.
try:
self.__spawn_event(xml)
except RestartStream:
return True
if root:
# Keep the root element empty of children to
# save on memory use.
root.clear()
logging.debug("Ending read XML loop")
def __spawn_event(self, xml):
"""
Analyze incoming XML stanzas and convert them into stanza
objects if applicable and queue stream events to be processed
by matching handlers.
Arguments:
xml -- The XML stanza to analyze.
"""
logging.debug("RECV: %s" % tostring(xml,
xmlns=self.default_ns,
stream=self))
# Apply any preprocessing filters.
xml = self.incoming_filter(xml)
# Convert the raw XML object into a stanza object. If no registered
# stanza type applies, a generic StanzaBase stanza will be used.
stanza_type = StanzaBase
for stanza_class in self.__root_stanza:
if xml.tag == "{%s}%s" % (self.default_ns, stanza_class.name):
stanza_type = stanza_class
break
stanza = stanza_type(self, xml)
# Match the stanza against registered handlers. Handlers marked
# to run "in stream" will be executed immediately; the rest will
# be queued.
unhandled = True
for handler in self.__handlers:
if handler.match(stanza):
stanza_copy = stanza_type(self, copy.deepcopy(xml))
handler.prerun(stanza_copy)
self.event_queue.put(('stanza', handler, stanza_copy))
if handler.checkDelete():
self.__handlers.pop(self.__handlers.index(handler))
unhandled = False
# Some stanzas require responses, such as Iq queries. A default
# handler will be executed immediately for this case.
if unhandled:
stanza.unhandled()
def _event_runner(self):
"""
Process the event queue and execute handlers.
The number of event runner threads is controlled by HANDLER_THREADS.
Stream event handlers will all execute in this thread. Custom event
handlers may be spawned in individual threads.
"""
logging.debug("Loading event runner")
while self.run:
try:
event = self.event_queue.get(True, timeout=5)
except queue.Empty:
event = None
except KeyboardInterrupt:
self.run = False
self.scheduler.run = False
if event is None:
continue
etype, handler = event[0:2]
args = event[2:]
if etype == 'stanza':
try:
handler.run(args[0])
except Exception as e:
error_msg = 'Error processing stream handler: %s'
logging.exception(error_msg % handler.name)
args[0].exception(e)
elif etype == 'schedule':
try:
logging.debug(args)
handler(*args[0])
except:
logging.exception('Error processing scheduled task')
elif etype == 'event':
func, threaded, disposable = handler
try:
if threaded:
x = threading.Thread(name="Event_%s" % str(func),
target=func,
args=args)
x.start()
else:
func(*args)
except:
logging.exception('Error processing event handler: %s')
elif etype == 'quit':
logging.debug("Quitting event runner thread")
return False
def _send_thread(self):
"""
Extract stanzas from the send queue and send them on the stream.
"""
while self.run:
data = self.send_queue.get(True)
logging.debug("SEND: %s" % data)
try:
self.socket.send(data.encode('utf-8'))
except:
logging.warning("Failed to send %s" % data)
self.state.set('connected', False)
if self.state.reconnect:
logging.exception("Disconnected. Socket Error.")
self.disconnect(reconnect=True)