"""Async sockets, build on top of Sam Rushing's excellent async library"""

import asyncore
import socket
from socket import AF_INET, SOCK_STREAM
import string
import cStringIO
import mimetools
import httplib


__version__ = "0.9"
__author__ = "jvr"

BUFSIZE = 512

VERBOSE = 1

class Server(asyncore.dispatcher):
	
	"""Generic asynchronous server class"""
	
	def __init__(self, port, handler_class, backlog=1, host=""):
		"""arguments:
		- port: the port to listen to
		- handler_class: class to handle requests
		- backlog: backlog queue size (optional) (don't fully understand, see socket docs)
		- host: host name (optional: can be empty to use default host name)
		"""
		if VERBOSE:
			print "Starting", self.__class__.__name__
		self.handler_class = handler_class
		asyncore.dispatcher.__init__(self)
		self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
		self.bind((host, port))
		self.listen(backlog)
	
	def handle_accept(self):
		conn, addr = self.accept()
		if VERBOSE:
			print 'Incoming Connection from %s:%d' % addr
		self.handler_class(conn)


class ProxyServer(Server):
	
	"""Generic proxy server class"""
	
	def __init__(self, port, handler_class, proxyaddr=None, closepartners=0):
		"""arguments:
		- port: the port to listen to
		- handler_class: proxy class to handle requests
		- proxyaddr: a tuple containing the address and 
		  port of a remote host to connect to (optional)
		- closepartners: boolean, specifies whether we should close
		  all proxy connections or not (optional). http seems to *not*
		  want this, but telnet does...
		"""
		Server.__init__(self, port, handler_class, 1, "")
		self.proxyaddr = proxyaddr
		self.closepartners = closepartners
	
	def handle_accept(self):
		conn, addr = self.accept()
		if VERBOSE:
			print 'Incoming Connection from %s:%d' % addr
		self.handler_class(conn, self.proxyaddr, closepartner=self.closepartners)


class Connection(asyncore.dispatcher):
	
	"""Generic connection class"""
	
	def __init__(self, sock_or_address=None, readfunc=None, terminator=None):
		"""arguments: 
		- sock_or_address: either a socket, or a tuple containing the name 
		and port number of a remote host
		- readfunc: callback function (optional). Will be called whenever
		  there is some data available, or when an appropraite terminator
		  is found.
		- terminator: string which specifies when a read is complete (optional)"""
		self._out_buffer = ""
		self._in_buffer = ""
		self.readfunc = readfunc
		self.terminator = terminator
		asyncore.dispatcher.__init__(self)
		if hasattr(sock_or_address, "fileno"):
			self.set_socket(sock_or_address)
		else:
			sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
			sock.setblocking(0)
			self.set_socket(sock)
			if sock_or_address:
				self.connect(sock_or_address)
	
	# public methods
	def send(self, data):
		self._out_buffer = self._out_buffer + data
	
	def recv(self, bytes=-1):
		if bytes == -1:
			bytes = len(self._in_buffer)
		data = self._in_buffer[:bytes]
		self._in_buffer = self._in_buffer[bytes:]
		return data
	
	def set_terminator(self, terminator):
		self.terminator = terminator
	
	# override this if you want to control the incoming data stream 
	def handle_incoming_data(self, data):
		if self.readfunc:
			if self.terminator:
				self._in_buffer = self._in_buffer + data
				pos = string.find(self._in_buffer, self.terminator)
				if pos < 0:
					return
				data = self._in_buffer[:pos]
				self._in_buffer = self._in_buffer[pos + len(self.terminator):]
				self.readfunc(data)
			else:
				self.readfunc(self._in_buffer + data)
				self._in_buffer = ""
		else:
			self._in_buffer = self._in_buffer + data
	
	# internal muck
	def handle_read(self):
		data = asyncore.dispatcher.recv(self, BUFSIZE)
		if data:
			if VERBOSE > 2:
				print "incoming ->", "%x" % id(self), `data`
			self.handle_incoming_data(data)
	
	def handle_write(self):
		if self._out_buffer:
			sent = self.socket.send(self._out_buffer[:BUFSIZE])
			if VERBOSE > 2:
				print "outgoing ->", "%x" % id(self), `self._out_buffer[:sent]`
			self._out_buffer = self._out_buffer[sent:]
	
	def close(self):
		if self.readfunc and self._in_buffer:
			self.readfunc(self._in_buffer)
			self._in_buffer = ""
		#elif VERBOSE > 1 and self._in_buffer:
		#	print "--- there is unread data:", `self._in_buffer`
		asyncore.dispatcher.close(self)
	
	def handle_close(self):
		self.close()
	
	def handle_connect(self):
		pass


class ConnectionUI:
	
	"""Glue to let a connection tell things to the UI in a standardized way.
	
	The protocoll defines four functions, which the connection will call:
	
		def settotal(int total): gets called when the connection knows the data size
		def setcurrent(int current): gets called when some new data has arrived
		def done(): gets called when the transaction is complete
		def error(type, value, tb): gets called wheneven an error occured
	"""
	
	def __init__(self, settotal_func, setcurrent_func, done_func, error_func):
		self.settotal = settotal_func
		self.setcurrent = setcurrent_func
		self.done = done_func
		self.error = error_func


class HTTPError(socket.error): pass


class HTTPClient(Connection, httplib.HTTP):
	
	"""Asynchronous HTTP connection"""
	
	def __init__(self, (host, port), datahandler, ui=None):
		Connection.__init__(self, (host, port))
		self.datahandler = datahandler
		self.ui = ui
		self.buf = ""
		self.doneheaders = 0
		self.done = 0
		self.headers = None
		self.length = None
		self.pos = 0
	
	def getreply(self):
		raise TypeError, "getreply() is not supported in async HTTP connection"
	
	def handle_incoming_data(self, data):
		assert not self.done
		if not self.doneheaders:
			self.buf = self.buf + data
			pos = string.find(self.buf, "\r\n\r\n")
			if pos >= 0:
				self.handle_reply(self.buf[:pos+4])
				length = self.headers.getheader("Content-Length")
				if length is not None:
					self.length = int(length)
					if self.ui is not None:
						self.ui.settotal(self.length)
				else:
					self.length = -1
				self.doneheaders = 1
				self.handle_data(self.buf[pos+4:])
				self.buf = ""
		else:
			self.handle_data(data)
	
	def handle_reply(self, data):
		f = cStringIO.StringIO(data)
		ver, code, msg = string.split(f.readline(), None, 2)
		code = int(code)
		msg = string.strip(msg)
		if code <> 200:
			# Hm, this is what *I* need, but probably not correct...
			raise HTTPError, (code, msg)
		self.headers = mimetools.Message(f)
	
	def handle_data(self, data):
		self.pos = self.pos + len(data)
		if self.ui is not None:
			self.ui.setcurrent(self.pos)
		self.datahandler(data)
		if self.pos >= self.length:
			self.datahandler("")
			self.done = 1
			if self.ui is not None:
				self.ui.done()
	
	def handle_error(self, type, value, tb):
		if self.ui is not None:
			self.ui.error(type, value, tb)
		else:
			Connection.handle_error(self, type, value, tb)
	
	def log(self, message):
		if VERBOSE:
			print 'LOG:', message


class PyMessage:
	
	def __init__(self):
		self._buf = ""
		self._len = None
		self._checksum = None
	
	def feed(self, data):
		self._buf = self._buf + data
		if self._len is None:
			if len(self._buf) >= 8:
				import struct
				self._len, self._checksum = struct.unpack("ll", self._buf[:8])
				self._buf = self._buf[8:]
		if self._len is not None:
			if len(self._buf) >= self._len:
				import zlib
				data = self._buf[:self._len]
				leftover = self._buf[self._len:]
				self._buf = None
				assert self._checksum == zlib.adler32(data), "corrupt data"
				self.data = data
				return 1, leftover
			else:
				return 0, None
		else:
			return 0, None


class PyConnection(Connection):
	
	def __init__(self, sock_or_address):
		Connection.__init__(self, sock_or_address)
		self.currentmessage = PyMessage()
	
	def handle_incoming_data(self, data):
		while data:
			done, data = self.currentmessage.feed(data)
			if done:
				import cPickle
				self.handle_object(cPickle.loads(self.currentmessage.data))
				self.currentmessage = PyMessage()
	
	def handle_object(self, object):
		print 'unhandled object:', `object`
	
	def send(self, object):
		import cPickle, zlib, struct
		data = cPickle.dumps(object, 1)
		length = len(data)
		checksum = zlib.adler32(data)
		data = struct.pack("ll", length, checksum) + data
		Connection.send(self, data)


class Echo(Connection):
	
	"""Simple echoing connection: it sends everything back it receives.""" 
	
	def handle_incoming_data(self, data):
		self.send(data)


class Proxy(Connection):
	
	"""Generic proxy connection"""
	
	def __init__(self, sock_or_address=None, proxyaddr=None, closepartner=0):
		"""arguments:
		- sock_or_address is either a socket or a tuple containing the 
		name and port number of a remote host
		- proxyaddr: a tuple containing a name and a port number of a 
		  remote host (optional).
		- closepartner: boolean, specifies whether we should close
		  the proxy connection (optional)"""
		
		Connection.__init__(self, sock_or_address)
		self.other = None
		self.proxyaddr = proxyaddr
		self.closepartner = closepartner
	
	def close(self):
		if self.other:
			other = self.other
			self.other = None
			other.other = None
			if self.closepartner:
				other.close()
		Connection.close(self)
	
	def handle_incoming_data(self, data):
		if not self.other:
			# pass data for possible automatic remote host detection
			# (see HTTPProxy)
			data = self.connectproxy(data)
		self.other.send(data)
	
	def connectproxy(self, data):
		other = self.__class__(self.proxyaddr, closepartner=self.closepartner)
		self.other = other
		other.other = self
		return data


class HTTPProxy(Proxy):
	
	"""Simple, useless, http proxy. It figures out itself where to connect to."""
	
	def connectproxy(self, data):
		if VERBOSE:
			print "--- proxy request", `data`
		addr, data = de_proxify(data)
		other = Proxy(addr)
		self.other = other
		other.other = self
		return data


# helper for HTTPProxy
def de_proxify(data):
	import re
	req_pattern = "GET http://([a-zA-Z0-9-_.]+)(:([0-9]+))?"
	m = re.match(req_pattern, data)
	host, dummy, port = m.groups()
	if not port:
		port = 80
	else:
		port = int(port)
	# change "GET http://xx.xx.xx/yy" into "GET /yy"
	data = re.sub(req_pattern, "GET ", data)
	return (host, port), data


# if we're running "under W", let's register the socket poller to the event loop
try:
	import W
except:
	pass
else:
	W.getapplication().addidlefunc(asyncore.poll)


## testing muck
#testserver = Server(10000, Connection)
#echoserver = Server(10007, Echo)
#httpproxyserver = Server(8088, HTTPProxy, 5)
#asyncore.close_all()