net-httpserver/webserver/asyncserver.py

import socket, select
import os.path, mimetypes

class Server(object):
	"""
	Asynchronous server class. specify a client handler class and port in the constructor.
	"""
	def __init__(self, connection_class, port=8080):
		self.port = port
		self.connection_class = connection_class
		self.listening_socket = socket.socket()
		self.listening_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
		self.listening_socket.bind(('127.0.0.1', port))
		self.listening_socket.listen(5)
		self.listening_socket.setblocking(0)
		self.handlers = {self.listening_socket: self}
		self.clients = []
	def run(self):
		"""
		run the event loop
		- collect sockets and min timeout
		- do the select call and notify clients
		"""
		reads = [self.listening_socket] + [c.sock for c in self.clients]
		writes = [c.sock for c in self.clients if c.should_write()]
		others = [c.sock for c in self.clients]
		try:
			timeout = min([c.next_timeout() for c in self.clients])
		except ValueError:
			timeout = None
		[rlist, wlist, xlist] = select.select(reads, writes, others, timeout)
		for readable in rlist:
			self.handlers[readable].do_read()
		for writable in wlist:
			self.handlers[writable].do_write()
		for otherable in xlist:
			self.handlers[otherable].do_other()
		for c in self.clients:
			c.try_timeout()
	def do_read(self):
		"""
		do_read method on the server itself (it's also in the select).
		accepts a connection.
		"""
		(sock, addrinfo) = self.listening_socket.accept()
		c = self.connection_class(self, sock, addrinfo)
		self.clients.append(c)
		self.handlers[sock] = c
	def client_closed(self, c):
		"""
		remove a client from the list and handlers
		"""
		self.clients.remove(c)
		del self.handlers[c.sock]
		# print "%d open connections" % len(self.clients)
	def close(self):
		""" close the server down and stop listening """
		self.listening_socket.close()

class Client(object):
	"""Client is the generic Server handler class. look at HTTPClient for more documentation"""
	def __init__(self, parent, sock, addrinfo):
		self.parent = parent
		self.sock = sock
		self.sock.setblocking(0)
		self.addrinfo = addrinfo
		self.write_buf = ""
		self.read_buf = ""
		self.to_close = False
		#self.write("test")
		# self.close()
	def should_write(self):
		return len(self.write_buf) > 0 or self.to_close
	def do_read(self):
		"""called by the event loop when the socket is readable"""
		data = self.sock.recv(4096)
		if not data: return self.close()
		self.read_buf += data
		self.on_data()
	def do_write(self):
		"""called by the event loop when the socket is writable"""
		try:
			if self.write_buf:
				no_written = self.sock.send(self.write_buf)
				self.write_buf = self.write_buf[no_written:]
			if len(self.write_buf) == 0 and self.to_close:
				self.sock.close()
				self.parent.client_closed(self)
		except socket.error:
			self.on_error()
	def on_data(self): raise NotImplementedError()
	def do_other(self): pass
	def on_error(self):
			self.parent.client_closed(self)
	def try_timeout(self): pass
	def next_timeout(self):
		return None
	def write(self, msg):
		self.write_buf += msg
	def close(self):
		self.to_close = True

class EchoClient(Client):
	"""EchoClient is an example Client handler that implements an echo server"""
	def __init__(self, parent, sock, addrinfo):
		super(EchoClient, self).__init__(parent, sock, addrinfo)
	def on_data(self):
		self.write(self.read_buf)
		self.read_buf = ""