#!/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
CONNECT_MAX = 18 # Max channels open per socket (freenet limit)
# No user-serviceable parts below this line
import sys, json, exceptions, getopt, urlparse, time, socket
import threading, Queue, SocketServer
import irc.client, logging
version = "1.0"
# Sketch of implementation:
#
# One Irker object manages multiple IRC sessions. Each Session object
# corresponds to a destination IRC URL that the daemon has seen and handles
# traffic for one channel on one server. There is never more than one
# Session per given (server, channel) pair.
#
# Multiple sessions to the same IRC server may share the same
# irc.client.ServerConnection object in order to cut down on open sockets,
# but because many servers enforce a limit on channels open per incoming
# socket, not *all* sessions on the same server necessarily do.
#
# Sessions 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 Session 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 SessionException(exceptions.Exception):
def __init__(self, message):
exceptions.Exception.__init__(self)
self.message = message
class Session():
"IRC session and message queue processing."
def __init__(self, irker, url):
self.irker = irker
self.url = url
self.server = None
self.last_xmit = time.time()
self.last_ping = time.time()
# Server connection setup
parsed = urlparse.urlparse(url)
host, _, port = parsed.netloc.partition(':')
if not port:
port = 6667
self.servername = host
self.channel = parsed.path.lstrip('/')
self.port = int(port)
# The consumer thread
self.queue = Queue.Queue()
self.thread = threading.Thread(target=self.dequeue)
self.thread.start()
def enqueue(self, message):
"Enque a message for transmission."
self.queue.put(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.server:
self.server = self.irker.open(self.servername,
self.port)
self.irker.debug(1, "XMIT_TTL bump (connection) at %s" % time.asctime())
self.last_xmit = time.time()
elif self.queue.empty():
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 at %s" % time.asctime())
self.irker.close(self.servername, self.port)
self.server = None
break
elif self.server.nick_accepted:
message = self.queue.get()
if self.channel not in self.server.channels_joined:
self.server.join("#" + self.channel)
self.server.channels_joined.append(self.channel)
self.server.privmsg("#" + self.channel, message)
self.last_xmit = time.time()
self.irker.debug(1, "XMIT_TTL bump (transmission) at %s" % time.asctime())
self.queue.task_done()
def terminate(self):
"Terminate this session"
self.server.quit("#" + self.channel)
self.server.close()
def await(self):
"Block until processing of all queued messages is done."
self.queue.join()
class Irker:
"Persistent IRC multiplexer."
def __init__(self, debuglevel=0):
self.debuglevel = debuglevel
self.irc = irc.client.IRC()
self.irc.add_global_handler("ping",
lambda c, e: self._handle_ping(c,e))
self.irc.add_global_handler("welcome",
lambda c, e: self._handle_welcome(c,e))
self.irc.add_global_handler("erroneusnickname",
lambda c, e: self._handle_badnick(c,e))
self.irc.add_global_handler("nicknameinuse",
lambda c, e: self._handle_badnick(c,e))
self.irc.add_global_handler("nickcollision",
lambda c, e: self._handle_badnick(c,e))
self.irc.add_global_handler("unavailresource",
lambda c, e: self._handle_badnick(c,e))
thread = threading.Thread(target=self.irc.process_forever)
self.irc._thread = thread
thread.start()
self.sessions = {}
self.countmap = {}
self.servercount = 0
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 nickname(self, n):
"Return a name for the nth server connection."
return (NAMESTYLE % n)
def open(self, servername, port):
"Allocate a new server instance."
if not (servername, port) in self.countmap:
self.countmap[(servername, port)] = (CONNECT_MAX+1, None)
count = self.countmap[(servername, port)][0]
if count > CONNECT_MAX:
self.servercount += 1
newserver = self.irc.server()
newserver.nick_trial = self.servercount
newserver.channels_joined = []
newserver.connect(servername,
port,
nickname=self.nickname(newserver.nick_trial),
username="irker",
ircname="irker relaying client")
newserver.nick_accepted = False
self.countmap[(servername, port)] = (1, newserver)
self.debug(1, "new server connection %d opened for %s:%s" % \
(self.servercount, servername, port))
else:
self.debug(1, "reusing server connection for %s:%s" % \
(servername, port))
return self.countmap[(servername, port)][1]
def close(self, servername, port):
"Release a server instance and all sessions using it."
del self.countmap[(servername, port)]
for val in self.sessions.values():
if (val.servername, val.port) == (servername, port):
self.sessions[val.url].terminate()
del self.sessions[val.url]
def _handle_ping(self, connection, event):
"PING arrived, bump the last-received time for the connection."
for (name, session) in self.sessions.items():
if name == connection.server:
session.last_ping = time.time()
def _handle_welcome(self, connection, event):
"Welcome arrived, nick accepted for this connection."
connection.nick_accepted = True
self.debug(1, "nick %s accepted" % self.nickname(connection.nick_trial))
def _handle_badnick(self, connection, event):
"Nick not accepted for this connection."
self.debug(1, "nick %s rejected" % self.nickname(connection.nick_trial))
connection.nick_trial += 1
connection.nick(self.nickname(connection.nick_trial))
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:
if url not in self.sessions:
self.sessions[url] = Session(self, url)
self.sessions[url].enqueue(message)
except ValueError:
self.logerr("can't recognize JSON on input: %s" % repr(line))
def terminate(self):
"Ship all pending messages before terminating."
for session in self.sessions.values():
session.await()
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__':
host = HOST
port = PORT
debuglevel = 0
(options, arguments) = getopt.getopt(sys.argv[1:], "d:p:V")
for (opt, val) in options:
if opt == '-d': # Enable debug/progress messages
debuglevel = int(val)
if debuglevel > 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=debuglevel)
tcpserver = SocketServer.TCPServer((host, port), IrkerTCPHandler)
udpserver = SocketServer.UDPServer((host, port), IrkerUDPHandler)
threading.Thread(target=tcpserver.serve_forever).start()
threading.Thread(target=udpserver.serve_forever).start()
# end