simple.py

#!/usr/bin/env python
#coding=utf8

import ssl
import time
import socket
import select
import logging
from sjrpc.core import RpcConnection, ConnectionManager

class SimpleRpcServer(ConnectionManager):
    '''
    A simple RPC Server that wait for new connections and dispatch messages
    from thoses are already established.
    
    :param sock: the :class:`socket` object to bind to the server connection
    :param default_handler: the default handler to bind to the new client 
        connections
    '''
    
    def __init__(self, sock, default_handler=None, on_disconnect=None):
        super(SimpleRpcServer, self).__init__()
        sock.setblocking(False)
        self._listening_sock = sock
        self.register(sock, self._handle_master_event)
        self._clients = {}
        self._default_handler = default_handler
        self._on_disconnect = on_disconnect

    def _accept_connection(self):
        return self._listening_sock.accept()

    def shutdown(self):
        super(SimpleRpcServer, self).shutdown()
        time.sleep(ConnectionManager.POLL_TIMEOUT)
        for connection in self._clients.values():
            connection.shutdown(self._on_disconnect)
        self._listening_sock.close()

    def shutdown_client(self, fd):
        conn = self._clients.get(fd)
        try:
            self.unregister(fd)
        except IOError:
            pass
        if fd is not None:
            try:
                del self._clients[fd]
            except KeyError:
                pass
            if conn is not None:
                conn.shutdown(callback=self._on_disconnect)

    def all_connections(self):
        return set(self._clients.values())

    def _handle_master_event(self, fd, events):
        # Event concerns the listening socket:
        if events & select.EPOLLIN:
            accepted = self._accept_connection()
            if accepted is not None:
                sock, address = accepted
                sock.setblocking(False)
                connection = RpcConnection(sock, self, 
                                           handler=self._default_handler)
                self.register(connection.get_fd(), self._handle_client_event)
                self._clients[connection.get_fd()] = connection

    def _handle_client_event(self, fd, events):
        connection = self._clients[fd]

        if events & select.EPOLLIN:
            # Data are ready to be readed on socket
            try:
                connection.receive()
            except socket.error as err:
                logging.debug('Socket error while receiving from client '
                              'fd/%s: %s', fd, err)
                self.shutdown_client(fd)
            except Exception as err:
                logging.debug('Unknown error while receiving from client '
                              'fd/%s: %s', fd, err)
                self.shutdown_client(fd)

        if events & select.EPOLLOUT:
            # Data are ready to be written on socket
            try:
                connection.send()
            except socket.error as err:
                logging.debug('Socket error while sending to the client '
                              'fd/%s: %s', fd, err)
                self.shutdown_client(fd)
            except Exception as err:
                logging.debug('Unknown error while sending to the client '
                              'fd/%s: %s', fd, err)
                self.shutdown_client(fd)

        if events & select.EPOLLHUP:
            logging.debug('Socket HUP fd/%s', fd)
            self.shutdown_client(fd)


class SimpleSslRpcServer(SimpleRpcServer):
    '''
    A simple RPC Server that wait for new connections and dispatch messages
    from thoses are already established. This server version enable SSL on
    client sockets.
    
    :param sock: the :class:`socket` object to bind to the server connection
    :param default_handler: the default handler to bind to the new client 
        connections
    '''

    def __init__(self, sock, certfile=None, keyfile=None, **kwargs):
        self._certfile = certfile
        self._keyfile = keyfile
        super(SimpleSslRpcServer, self).__init__(sock, **kwargs)

    def _accept_connection(self):
        sock, address = self._listening_sock.accept()
        try:
            sslsock = ssl.wrap_socket(sock, server_side=True,
                                      keyfile=self._keyfile,
                                      certfile=self._certfile,
                                      ssl_version=ssl.PROTOCOL_TLSv1,
                                      do_handshake_on_connect=True)
        except ssl.SSLError as err:
            logging.debug('Error when accepting ssl connection: %s', err)
        else:
            return sslsock, address