#!/usr/bin/env python
"""
irker - a simple IRC multiplexer daemon
Listens for JSON objects of the form {'to':<irc-url>, 'privmsg':<text>}
and relays messages to IRC channels. Each request must be followed by
a newline.
The <text> must be a string. The value of the 'to' attribute can be a
string containing an IRC URL (e.g. 'irc://chat.freenet.net/botwar') or
a list of such strings; in the latter case the message is broadcast to
all listed channels. Note that the channel portion of the URL will
*not* have a leading '#' unless the channel name itself does.
Options: -p sets the listening port. The -V option prints the program
version and exits.
Requires Python 2.6 and the irc.client library at version >= 2.0.2: see
http://sourceforge.net/projects/python-irclib
"""
# These things might need tuning
HOST = "localhost"
PORT = 4747 # Overridden by -p option
NAMESTYLE = "irker%03d" # IRC nick template - must contain '%d'
XMIT_TTL = (3 * 60 * 60) # Time to live, seconds from last transmit
PING_TTL = (15 * 60) # Time to live, seconds from last PING
DISCONNECT_TTL = (24 * 60 * 60) # Time to live, seconds from last connect
UNSEEN_TTL = 60 # Time to live, seconds since first request
CHANNEL_MAX = 18 # Max channels open per socket (freenet limit)
# No user-serviceable parts below this line
import sys, json, exceptions, getopt, urlparse, time
import threading, Queue, SocketServer
import irc.client, logging
version = "1.0"
# Sketch of implementation:
#
# One Irker object manages multiple IRC sessions. It holds a map of
# Dispatcher objects, one per (server, port) combination, which are
# responsible for routing messages to one of any number of Connection
# objects that do the actual socket conversations. The reason for
# the Dispatcher layer is that IRC daemons limit the number of channels
# a client (that is, from the daemon's point of view, a socket) can be
# joined to, so we may need a flock of connection instances each with
# its own socket.
#
# Connections are timed out and removed when either they haven't seen a
# PING for a while (indicating that the server may be stalled or down)
# or there has been no message traffic to them for a while.
#
# There are multiple threads. One accepts incoming traffic from all servers.
# Each Connection also has a consumer thread and a thread-safe message queue.
# The program main appends messages to queues as JSON requests are received;
# the consumer threads try to ship them to servers. When a socket write
# stalls, it only blocks an individual consumer thread; if it stalls long
# enough, the session will be timed out.
#
# Message delivery is thus not reliable in the face of network stalls, but
# this was considered acceptable because IRC (notoriously) has the same
# problem - there is little point in delivery to a relay that is down or
# unreliable.
class Connection:
def __init__(self, irker, servername, port):
self.irker = irker
self.servername = servername
self.port = port
self.connection = None
self.status = "unseen"
self.nick_trial = 1
self.last_xmit = time.time()
self.last_ping = time.time()
self.channels_joined = []
# The consumer thread
self.queue = Queue.Queue()
self.thread = threading.Thread(target=self.dequeue)
self.thread.start()
def nickname(self, n=None):
"Return a name for the nth server connection."
if n is None:
n = self.nick_trial
return (NAMESTYLE % n)
def handle_ping(self):
"Register the fact that the server has pinged this connection."
self.last_ping = time.time()
def handle_welcome(self):
"The server says we're OK, with a non-conflicting nick."
self.status = "ready"
self.irker.debug(1, "nick %s accepted" % self.nickname())
def handle_badnick(self):
"The server says our nick has a conflict."
self.irker.debug(1, "nick %s rejected" % self.nickname())
self.nick_trial += 1
self.nick(self.nickname())
def enqueue(self, channel, message):
"Enque a message for transmission."
self.queue.put((channel, message))
def dequeue(self):
"Try to ship pending messages from the queue."
while True:
# We want to be kind to the IRC servers and not hold unused
# sockets open forever, so they have a time-to-live. The
# loop is coded this particular way so that we can drop
# the actual server connection when its time-to-live
# expires, then reconnect and resume transmission if the
# queue fills up again.
if not self.connection:
self.connection = self.irker.irc.server()
self.connection.context = self
self.nick_trial = 1
self.channels_joined = []
# This will throw irc.client.ServerConnectionError on failure
try:
self.connection.connect(self.servername,
self.port,
nickname=self.nickname(),
username="irker",
ircname="irker relaying client")
self.status = "handshaking"
self.irker.debug(1, "XMIT_TTL bump (%s connection) at %s" % (self.servername, time.asctime()))
self.last_xmit = time.time()
except irc.client.ServerConnectionError:
self.status = "disconnected"
elif self.queue.empty():
# Queue is empty, at some point we want to time out
# the connection rather than holding a socket open in
# the server forever.
now = time.time()
if now > self.last_xmit + XMIT_TTL \
or now > self.last_ping + PING_TTL:
self.irker.debug(1, "timing out inactive connection to %s at %s" % (self.servername, time.asctime()))
self.connection.context = None
self.connection.close()
self.connection = None
self.status = "disconnected"
elif self.status == "disconnected" \
and time.time() > self.last_xmit + DISCONNECT_TTL:
# Queue is nonempty, but the IRC server might be down. Letting
# failed connections retain queue space forever would be a
# memory leak.
self.status = "expired"
break
elif self.status == "unseen" \
and time.time() > self.last_xmit + UNSEEN_TTL:
# Nasty people could attempt a denial-of-service
# attack by flooding us with requests with invalid
# servernames. We guard against this by rapidly
# expiring connections that have a nonempty queue but
# have never had a successful open.
self.status = "expired"
break
elif self.status == "ready":
(channel, message) = self.queue.get()
if channel not in self.channels_joined:
self.connection.join("#" + channel)
self.channels_joined.append(channel)
self.connection.privmsg("#" + channel, message)
self.last_xmit = time.time()
self.irker.debug(1, "XMIT_TTL bump (%s transmission) at %s" % (self.servername, time.asctime()))
self.queue.task_done()
def live(self):
"Should this connection not be scavenged?"
return self.status != "expired"
def joined_to(self, channel):
"Is this connection joined to the specified channel?"
return channel in self.channels_joined
def accepting(self):
"Can this connection accept new channel joins?"
return len(self.channels_joined) < CHANNEL_MAX
class Target():
"Represent a transmission target."
def __init__(self, url):
parsed = urlparse.urlparse(url)
irchost, _, ircport = parsed.netloc.partition(':')
if not ircport:
ircport = 6667
self.servername = irchost
self.channel = parsed.path.lstrip('/')
self.port = int(ircport)
def server(self):
"Return a hashable tuple representing the destination server."
return (self.servername, self.port)
class Dispatcher:
"Manage connections to a particular server-port combination."
def __init__(self, irker, servername, port):
self.irker = irker
self.servername = servername
self.port = port
self.connections = []
def dispatch(self, channel, message):
"Dispatch messages for our server-port combination."
self.connections = [x for x in self.connections if x.live()]
eligibles = [x for x in self.connections if x.joined_to(channel)] \
or [x for x in self.connections if x.accepting()]
if not eligibles:
newconn = Connection(self.irker,
self.servername,
self.port)
self.connections.append(newconn)
eligibles = [newconn]
eligibles[0].enqueue(channel, message)
def live(self):
"Does this server-port combination have any live connections?"
self.connections = [x for x in self.connections if x.live()]
return not self.connections
class Irker:
"Persistent IRC multiplexer."
def __init__(self, debuglevel=0):
self.debuglevel = debuglevel
self.irc = irc.client.IRC()
self.irc.add_global_handler("ping", self._handle_ping)
self.irc.add_global_handler("welcome", self._handle_welcome)
self.irc.add_global_handler("erroneusnickname", self._handle_badnick)
self.irc.add_global_handler("nicknameinuse", self._handle_badnick)
self.irc.add_global_handler("nickcollision", self._handle_badnick)
self.irc.add_global_handler("unavailresource", self._handle_badnick)
self.irc.add_global_handler("featurelist", self._handle_features)
thread = threading.Thread(target=self.irc.process_forever)
self.irc._thread = thread
thread.start()
self.servers = {}
def logerr(self, errmsg):
"Log a processing error."
sys.stderr.write("irker: " + errmsg + "\n")
def debug(self, level, errmsg):
"Debugging information."
if self.debuglevel >= level:
sys.stderr.write("irker: %s\n" % errmsg)
def _handle_ping(self, connection, event):
"PING arrived, bump the last-received time for the connection."
if connection.context:
connection.context.handle_ping()
def _handle_welcome(self, connection, event):
"Welcome arrived, nick accepted for this connection."
if connection.context:
connection.context.handle_welcome()
def _handle_badnick(self, connection, event):
"Nick not accepted for this connection."
if connection.context:
connection.context.handle_badnick()
def _handle_features(self, connection, event):
"Determine if and how we can set deaf mode."
if connection.context:
for lump in event.arguments():
if lump.startswith("DEAF="):
connection.mode(connection.context.nickname(), "+"+lump[5:])
def drop_server(servername, port):
"Drop a server out of the server map."
del self.servers[(servername, port)]
def handle(self, line):
"Perform a JSON relay request."
try:
request = json.loads(line.strip())
if "to" not in request or "privmsg" not in request:
self.logerr("malformed reqest - 'to' or 'privmsg' missing: %s" % repr(request))
else:
channels = request['to']
message = request['privmsg']
if type(channels) not in (type([]), type(u"")) \
or type(message) != type(u""):
self.logerr("malformed request - unexpected types: %s" % repr(request))
else:
if type(channels) == type(u""):
channels = [channels]
for url in channels:
if type(url) != type(u""):
self.logerr("malformed request - unexpected type: %s" % repr(request))
else:
target = Target(url)
if target.server() not in self.servers:
self.servers[target.server()] = Dispatcher(self, target.servername, target.port)
self.servers[target.server()].dispatch(target.channel, message)
# GC dispatchers with no active connections
servernames = self.servers.keys()
for servername in servernames:
if not self.servers[servername].live():
del self.servers[servername]
except ValueError:
self.logerr("can't recognize JSON on input: %s" % repr(line))
class IrkerTCPHandler(SocketServer.StreamRequestHandler):
def handle(self):
while True:
irker.handle(self.rfile.readline().strip())
class IrkerUDPHandler(SocketServer.BaseRequestHandler):
def handle(self):
data = self.request[0].strip()
#socket = self.request[1]
irker.handle(data)
if __name__ == '__main__':
srvhost = HOST
srvport = PORT
debuglvl = 0
(options, arguments) = getopt.getopt(sys.argv[1:], "d:p:V")
for (opt, val) in options:
if opt == '-d': # Enable debug/progress messages
debuglvl = int(val)
if debuglvl > 1:
logging.basicConfig(level=logging.DEBUG)
elif opt == '-p': # Set the listening port
port = int(val)
elif opt == '-V': # Emit version and exit
sys.stdout.write("irker version %s\n" % version)
sys.exit(0)
irker = Irker(debuglevel=debuglvl)
tcpserver = SocketServer.TCPServer((srvhost, srvport), IrkerTCPHandler)
udpserver = SocketServer.UDPServer((srvhost, srvport), IrkerUDPHandler)
threading.Thread(target=tcpserver.serve_forever).start()
threading.Thread(target=udpserver.serve_forever).start()
# end