epoll_web_serv.py

#!/usr/bin/env python

"""
Simple web server using select.epoll
Using Python 2.7
code from python network programming cookbook
slightly modified
"""

import socket
import select
import argparse
SERVER_HOST = 'localhost'
EOL1 = b'\n\n'
EOL2 = b'\n\r\n'
SERVER_RESPONSE = b"""HTTP/1.1 200 OK\r\nDate: Mon, Jul 2014 21:37:01 \
        GMT\r\nContent-Type: text/plain\r\nContent-Length: 25\r\n\r\n \
        Hello from Epoll Server!"""

class EpollServer(object):
    """ a socket server using epoll """
    def __init__(self, host=SERVER_HOST, port=0):
        self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        self.sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        self.sock.bind((host, port))
        self.sock.listen(1)
        self.sock.setblocking(0)
        self.sock.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
        print "Started Epoll Server"
        self.epoll = select.epoll()
        self.epoll.register(self.sock.fileno(), select.EPOLLIN)

    def run(self):
        """ executes epoll server with an ak47 """
        try:
            connections = {}; requests = {}; responses= {}
            while True:
                events = self.epoll.poll(1)
                for fileno, event in events:
                    if fileno == self.sock.fileno():
                        connection, address = self.sock.accept()
                        connection.setblocking(0)
                        self.epoll.register(connection.fileno(), \
                                select.EPOLLIN)
                        connections[connection.fileno()] = connection
                        requests[connection.fileno()] = b''
                        responses[connection.fileno()] = SERVER_RESPONSE
                    elif event & select.EPOLLIN:
                        requests[fileno] += connections[fileno].recv(1024)
                        if EOL1 in requests[fileno] or EOL2 in requests [fileno]:
                            self.epoll.modify(fileno, select.EPOLLOUT)
                            print ('-' * 40 + '\n' + requests[fileno].decode() [:-2])
                        elif event & select.EPOLLOUT:
                            byteswritten = connections[fileno].send(responses[fileno])
                            responses[fileno] = responses[fileno] [byteswritten:]
                            if len(responses[fileno]) == 0:
                                self.epoll.modify(fileno, 0)
                                connections[fileno].shutdown(socket.SHUT_RDWR)
                            elif event & select.EPOLLHUP:
                                self.epoll.unregister(fileno)
                                connections[fileno].close()
                                del connections[fileno]

        finally:
            self.epoll.unregister(self.sock.fileno())
            self.epoll.close()
            self.sock.close()

if __name__ == '__main__':
    parser = argparse.ArgumentParser(description='Socket Server Example with Epoll')
    parser.add_argument('--port', action="store", dest="port", type=int, required=True)
    given_args = parser.parse_args()
    port = given_args.port
    server = EpollServer(host=SERVER_HOST, port=port)
    server.run()

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