| # -*- Mode: Python -*- |
| # Id: asyncore.py,v 2.51 2000/09/07 22:29:26 rushing Exp |
| # Author: Sam Rushing <rushing@nightmare.com> |
| |
| # ====================================================================== |
| # Copyright 1996 by Sam Rushing |
| # |
| # All Rights Reserved |
| # |
| # Permission to use, copy, modify, and distribute this software and |
| # its documentation for any purpose and without fee is hereby |
| # granted, provided that the above copyright notice appear in all |
| # copies and that both that copyright notice and this permission |
| # notice appear in supporting documentation, and that the name of Sam |
| # Rushing not be used in advertising or publicity pertaining to |
| # distribution of the software without specific, written prior |
| # permission. |
| # |
| # SAM RUSHING DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, |
| # INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN |
| # NO EVENT SHALL SAM RUSHING BE LIABLE FOR ANY SPECIAL, INDIRECT OR |
| # CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS |
| # OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, |
| # NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN |
| # CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
| # ====================================================================== |
| |
| """Basic infrastructure for asynchronous socket service clients and servers. |
| |
| There are only two ways to have a program on a single processor do "more |
| than one thing at a time". Multi-threaded programming is the simplest and |
| most popular way to do it, but there is another very different technique, |
| that lets you have nearly all the advantages of multi-threading, without |
| actually using multiple threads. it's really only practical if your program |
| is largely I/O bound. If your program is CPU bound, then pre-emptive |
| scheduled threads are probably what you really need. Network servers are |
| rarely CPU-bound, however. |
| |
| If your operating system supports the select() system call in its I/O |
| library (and nearly all do), then you can use it to juggle multiple |
| communication channels at once; doing other work while your I/O is taking |
| place in the "background." Although this strategy can seem strange and |
| complex, especially at first, it is in many ways easier to understand and |
| control than multi-threaded programming. The module documented here solves |
| many of the difficult problems for you, making the task of building |
| sophisticated high-performance network servers and clients a snap. |
| """ |
| |
| import select |
| import socket |
| import sys |
| import time |
| import warnings |
| |
| import os |
| from errno import EALREADY, EINPROGRESS, EWOULDBLOCK, ECONNRESET, EINVAL, \ |
| ENOTCONN, ESHUTDOWN, EINTR, EISCONN, EBADF, ECONNABORTED, EPIPE, EAGAIN, \ |
| errorcode |
| |
| _DISCONNECTED = frozenset((ECONNRESET, ENOTCONN, ESHUTDOWN, ECONNABORTED, EPIPE, |
| EBADF)) |
| |
| try: |
| socket_map |
| except NameError: |
| socket_map = {} |
| |
| def _strerror(err): |
| try: |
| return os.strerror(err) |
| except (ValueError, OverflowError, NameError): |
| if err in errorcode: |
| return errorcode[err] |
| return "Unknown error %s" %err |
| |
| class ExitNow(Exception): |
| pass |
| |
| _reraised_exceptions = (ExitNow, KeyboardInterrupt, SystemExit) |
| |
| def read(obj): |
| try: |
| obj.handle_read_event() |
| except _reraised_exceptions: |
| raise |
| except: |
| obj.handle_error() |
| |
| def write(obj): |
| try: |
| obj.handle_write_event() |
| except _reraised_exceptions: |
| raise |
| except: |
| obj.handle_error() |
| |
| def _exception(obj): |
| try: |
| obj.handle_expt_event() |
| except _reraised_exceptions: |
| raise |
| except: |
| obj.handle_error() |
| |
| def readwrite(obj, flags): |
| try: |
| if flags & select.POLLIN: |
| obj.handle_read_event() |
| if flags & select.POLLOUT: |
| obj.handle_write_event() |
| if flags & select.POLLPRI: |
| obj.handle_expt_event() |
| if flags & (select.POLLHUP | select.POLLERR | select.POLLNVAL): |
| obj.handle_close() |
| except socket.error, e: |
| if e.args[0] not in _DISCONNECTED: |
| obj.handle_error() |
| else: |
| obj.handle_close() |
| except _reraised_exceptions: |
| raise |
| except: |
| obj.handle_error() |
| |
| def poll(timeout=0.0, map=None): |
| if map is None: |
| map = socket_map |
| if map: |
| r = []; w = []; e = [] |
| for fd, obj in map.items(): |
| is_r = obj.readable() |
| is_w = obj.writable() |
| if is_r: |
| r.append(fd) |
| # accepting sockets should not be writable |
| if is_w and not obj.accepting: |
| w.append(fd) |
| if is_r or is_w: |
| e.append(fd) |
| if [] == r == w == e: |
| time.sleep(timeout) |
| return |
| |
| try: |
| r, w, e = select.select(r, w, e, timeout) |
| except select.error, err: |
| if err.args[0] != EINTR: |
| raise |
| else: |
| return |
| |
| for fd in r: |
| obj = map.get(fd) |
| if obj is None: |
| continue |
| read(obj) |
| |
| for fd in w: |
| obj = map.get(fd) |
| if obj is None: |
| continue |
| write(obj) |
| |
| for fd in e: |
| obj = map.get(fd) |
| if obj is None: |
| continue |
| _exception(obj) |
| |
| def poll2(timeout=0.0, map=None): |
| # Use the poll() support added to the select module in Python 2.0 |
| if map is None: |
| map = socket_map |
| if timeout is not None: |
| # timeout is in milliseconds |
| timeout = int(timeout*1000) |
| pollster = select.poll() |
| if map: |
| for fd, obj in map.items(): |
| flags = 0 |
| if obj.readable(): |
| flags |= select.POLLIN | select.POLLPRI |
| # accepting sockets should not be writable |
| if obj.writable() and not obj.accepting: |
| flags |= select.POLLOUT |
| if flags: |
| # Only check for exceptions if object was either readable |
| # or writable. |
| flags |= select.POLLERR | select.POLLHUP | select.POLLNVAL |
| pollster.register(fd, flags) |
| try: |
| r = pollster.poll(timeout) |
| except select.error, err: |
| if err.args[0] != EINTR: |
| raise |
| r = [] |
| for fd, flags in r: |
| obj = map.get(fd) |
| if obj is None: |
| continue |
| readwrite(obj, flags) |
| |
| poll3 = poll2 # Alias for backward compatibility |
| |
| def loop(timeout=30.0, use_poll=False, map=None, count=None): |
| if map is None: |
| map = socket_map |
| |
| if use_poll and hasattr(select, 'poll'): |
| poll_fun = poll2 |
| else: |
| poll_fun = poll |
| |
| if count is None: |
| while map: |
| poll_fun(timeout, map) |
| |
| else: |
| while map and count > 0: |
| poll_fun(timeout, map) |
| count = count - 1 |
| |
| class dispatcher: |
| |
| debug = False |
| connected = False |
| accepting = False |
| connecting = False |
| closing = False |
| addr = None |
| ignore_log_types = frozenset(['warning']) |
| |
| def __init__(self, sock=None, map=None): |
| if map is None: |
| self._map = socket_map |
| else: |
| self._map = map |
| |
| self._fileno = None |
| |
| if sock: |
| # Set to nonblocking just to make sure for cases where we |
| # get a socket from a blocking source. |
| sock.setblocking(0) |
| self.set_socket(sock, map) |
| self.connected = True |
| # The constructor no longer requires that the socket |
| # passed be connected. |
| try: |
| self.addr = sock.getpeername() |
| except socket.error, err: |
| if err.args[0] in (ENOTCONN, EINVAL): |
| # To handle the case where we got an unconnected |
| # socket. |
| self.connected = False |
| else: |
| # The socket is broken in some unknown way, alert |
| # the user and remove it from the map (to prevent |
| # polling of broken sockets). |
| self.del_channel(map) |
| raise |
| else: |
| self.socket = None |
| |
| def __repr__(self): |
| status = [self.__class__.__module__+"."+self.__class__.__name__] |
| if self.accepting and self.addr: |
| status.append('listening') |
| elif self.connected: |
| status.append('connected') |
| if self.addr is not None: |
| try: |
| status.append('%s:%d' % self.addr) |
| except TypeError: |
| status.append(repr(self.addr)) |
| return '<%s at %#x>' % (' '.join(status), id(self)) |
| |
| __str__ = __repr__ |
| |
| def add_channel(self, map=None): |
| #self.log_info('adding channel %s' % self) |
| if map is None: |
| map = self._map |
| map[self._fileno] = self |
| |
| def del_channel(self, map=None): |
| fd = self._fileno |
| if map is None: |
| map = self._map |
| if fd in map: |
| #self.log_info('closing channel %d:%s' % (fd, self)) |
| del map[fd] |
| self._fileno = None |
| |
| def create_socket(self, family, type): |
| self.family_and_type = family, type |
| sock = socket.socket(family, type) |
| sock.setblocking(0) |
| self.set_socket(sock) |
| |
| def set_socket(self, sock, map=None): |
| self.socket = sock |
| ## self.__dict__['socket'] = sock |
| self._fileno = sock.fileno() |
| self.add_channel(map) |
| |
| def set_reuse_addr(self): |
| # try to re-use a server port if possible |
| try: |
| self.socket.setsockopt( |
| socket.SOL_SOCKET, socket.SO_REUSEADDR, |
| self.socket.getsockopt(socket.SOL_SOCKET, |
| socket.SO_REUSEADDR) | 1 |
| ) |
| except socket.error: |
| pass |
| |
| # ================================================== |
| # predicates for select() |
| # these are used as filters for the lists of sockets |
| # to pass to select(). |
| # ================================================== |
| |
| def readable(self): |
| return True |
| |
| def writable(self): |
| return True |
| |
| # ================================================== |
| # socket object methods. |
| # ================================================== |
| |
| def listen(self, num): |
| self.accepting = True |
| if os.name == 'nt' and num > 5: |
| num = 5 |
| return self.socket.listen(num) |
| |
| def bind(self, addr): |
| self.addr = addr |
| return self.socket.bind(addr) |
| |
| def connect(self, address): |
| self.connected = False |
| self.connecting = True |
| err = self.socket.connect_ex(address) |
| if err in (EINPROGRESS, EALREADY, EWOULDBLOCK) \ |
| or err == EINVAL and os.name in ('nt', 'ce'): |
| self.addr = address |
| return |
| if err in (0, EISCONN): |
| self.addr = address |
| self.handle_connect_event() |
| else: |
| raise socket.error(err, errorcode[err]) |
| |
| def accept(self): |
| # XXX can return either an address pair or None |
| try: |
| conn, addr = self.socket.accept() |
| except TypeError: |
| return None |
| except socket.error as why: |
| if why.args[0] in (EWOULDBLOCK, ECONNABORTED, EAGAIN): |
| return None |
| else: |
| raise |
| else: |
| return conn, addr |
| |
| def send(self, data): |
| try: |
| result = self.socket.send(data) |
| return result |
| except socket.error, why: |
| if why.args[0] == EWOULDBLOCK: |
| return 0 |
| elif why.args[0] in _DISCONNECTED: |
| self.handle_close() |
| return 0 |
| else: |
| raise |
| |
| def recv(self, buffer_size): |
| try: |
| data = self.socket.recv(buffer_size) |
| if not data: |
| # a closed connection is indicated by signaling |
| # a read condition, and having recv() return 0. |
| self.handle_close() |
| return '' |
| else: |
| return data |
| except socket.error, why: |
| # winsock sometimes raises ENOTCONN |
| if why.args[0] in _DISCONNECTED: |
| self.handle_close() |
| return '' |
| else: |
| raise |
| |
| def close(self): |
| self.connected = False |
| self.accepting = False |
| self.connecting = False |
| self.del_channel() |
| try: |
| self.socket.close() |
| except socket.error, why: |
| if why.args[0] not in (ENOTCONN, EBADF): |
| raise |
| |
| # cheap inheritance, used to pass all other attribute |
| # references to the underlying socket object. |
| def __getattr__(self, attr): |
| try: |
| retattr = getattr(self.socket, attr) |
| except AttributeError: |
| raise AttributeError("%s instance has no attribute '%s'" |
| %(self.__class__.__name__, attr)) |
| else: |
| msg = "%(me)s.%(attr)s is deprecated. Use %(me)s.socket.%(attr)s " \ |
| "instead." % {'me': self.__class__.__name__, 'attr':attr} |
| warnings.warn(msg, DeprecationWarning, stacklevel=2) |
| return retattr |
| |
| # log and log_info may be overridden to provide more sophisticated |
| # logging and warning methods. In general, log is for 'hit' logging |
| # and 'log_info' is for informational, warning and error logging. |
| |
| def log(self, message): |
| sys.stderr.write('log: %s\n' % str(message)) |
| |
| def log_info(self, message, type='info'): |
| if type not in self.ignore_log_types: |
| print '%s: %s' % (type, message) |
| |
| def handle_read_event(self): |
| if self.accepting: |
| # accepting sockets are never connected, they "spawn" new |
| # sockets that are connected |
| self.handle_accept() |
| elif not self.connected: |
| if self.connecting: |
| self.handle_connect_event() |
| self.handle_read() |
| else: |
| self.handle_read() |
| |
| def handle_connect_event(self): |
| err = self.socket.getsockopt(socket.SOL_SOCKET, socket.SO_ERROR) |
| if err != 0: |
| raise socket.error(err, _strerror(err)) |
| self.handle_connect() |
| self.connected = True |
| self.connecting = False |
| |
| def handle_write_event(self): |
| if self.accepting: |
| # Accepting sockets shouldn't get a write event. |
| # We will pretend it didn't happen. |
| return |
| |
| if not self.connected: |
| if self.connecting: |
| self.handle_connect_event() |
| self.handle_write() |
| |
| def handle_expt_event(self): |
| # handle_expt_event() is called if there might be an error on the |
| # socket, or if there is OOB data |
| # check for the error condition first |
| err = self.socket.getsockopt(socket.SOL_SOCKET, socket.SO_ERROR) |
| if err != 0: |
| # we can get here when select.select() says that there is an |
| # exceptional condition on the socket |
| # since there is an error, we'll go ahead and close the socket |
| # like we would in a subclassed handle_read() that received no |
| # data |
| self.handle_close() |
| else: |
| self.handle_expt() |
| |
| def handle_error(self): |
| nil, t, v, tbinfo = compact_traceback() |
| |
| # sometimes a user repr method will crash. |
| try: |
| self_repr = repr(self) |
| except: |
| self_repr = '<__repr__(self) failed for object at %0x>' % id(self) |
| |
| self.log_info( |
| 'uncaptured python exception, closing channel %s (%s:%s %s)' % ( |
| self_repr, |
| t, |
| v, |
| tbinfo |
| ), |
| 'error' |
| ) |
| self.handle_close() |
| |
| def handle_expt(self): |
| self.log_info('unhandled incoming priority event', 'warning') |
| |
| def handle_read(self): |
| self.log_info('unhandled read event', 'warning') |
| |
| def handle_write(self): |
| self.log_info('unhandled write event', 'warning') |
| |
| def handle_connect(self): |
| self.log_info('unhandled connect event', 'warning') |
| |
| def handle_accept(self): |
| self.log_info('unhandled accept event', 'warning') |
| |
| def handle_close(self): |
| self.log_info('unhandled close event', 'warning') |
| self.close() |
| |
| # --------------------------------------------------------------------------- |
| # adds simple buffered output capability, useful for simple clients. |
| # [for more sophisticated usage use asynchat.async_chat] |
| # --------------------------------------------------------------------------- |
| |
| class dispatcher_with_send(dispatcher): |
| |
| def __init__(self, sock=None, map=None): |
| dispatcher.__init__(self, sock, map) |
| self.out_buffer = '' |
| |
| def initiate_send(self): |
| num_sent = 0 |
| num_sent = dispatcher.send(self, self.out_buffer[:512]) |
| self.out_buffer = self.out_buffer[num_sent:] |
| |
| def handle_write(self): |
| self.initiate_send() |
| |
| def writable(self): |
| return (not self.connected) or len(self.out_buffer) |
| |
| def send(self, data): |
| if self.debug: |
| self.log_info('sending %s' % repr(data)) |
| self.out_buffer = self.out_buffer + data |
| self.initiate_send() |
| |
| # --------------------------------------------------------------------------- |
| # used for debugging. |
| # --------------------------------------------------------------------------- |
| |
| def compact_traceback(): |
| t, v, tb = sys.exc_info() |
| tbinfo = [] |
| if not tb: # Must have a traceback |
| raise AssertionError("traceback does not exist") |
| while tb: |
| tbinfo.append(( |
| tb.tb_frame.f_code.co_filename, |
| tb.tb_frame.f_code.co_name, |
| str(tb.tb_lineno) |
| )) |
| tb = tb.tb_next |
| |
| # just to be safe |
| del tb |
| |
| file, function, line = tbinfo[-1] |
| info = ' '.join(['[%s|%s|%s]' % x for x in tbinfo]) |
| return (file, function, line), t, v, info |
| |
| def close_all(map=None, ignore_all=False): |
| if map is None: |
| map = socket_map |
| for x in map.values(): |
| try: |
| x.close() |
| except OSError, x: |
| if x.args[0] == EBADF: |
| pass |
| elif not ignore_all: |
| raise |
| except _reraised_exceptions: |
| raise |
| except: |
| if not ignore_all: |
| raise |
| map.clear() |
| |
| # Asynchronous File I/O: |
| # |
| # After a little research (reading man pages on various unixen, and |
| # digging through the linux kernel), I've determined that select() |
| # isn't meant for doing asynchronous file i/o. |
| # Heartening, though - reading linux/mm/filemap.c shows that linux |
| # supports asynchronous read-ahead. So _MOST_ of the time, the data |
| # will be sitting in memory for us already when we go to read it. |
| # |
| # What other OS's (besides NT) support async file i/o? [VMS?] |
| # |
| # Regardless, this is useful for pipes, and stdin/stdout... |
| |
| if os.name == 'posix': |
| import fcntl |
| |
| class file_wrapper: |
| # Here we override just enough to make a file |
| # look like a socket for the purposes of asyncore. |
| # The passed fd is automatically os.dup()'d |
| |
| def __init__(self, fd): |
| self.fd = os.dup(fd) |
| |
| def recv(self, *args): |
| return os.read(self.fd, *args) |
| |
| def send(self, *args): |
| return os.write(self.fd, *args) |
| |
| def getsockopt(self, level, optname, buflen=None): |
| if (level == socket.SOL_SOCKET and |
| optname == socket.SO_ERROR and |
| not buflen): |
| return 0 |
| raise NotImplementedError("Only asyncore specific behaviour " |
| "implemented.") |
| |
| read = recv |
| write = send |
| |
| def close(self): |
| os.close(self.fd) |
| |
| def fileno(self): |
| return self.fd |
| |
| class file_dispatcher(dispatcher): |
| |
| def __init__(self, fd, map=None): |
| dispatcher.__init__(self, None, map) |
| self.connected = True |
| try: |
| fd = fd.fileno() |
| except AttributeError: |
| pass |
| self.set_file(fd) |
| # set it to non-blocking mode |
| flags = fcntl.fcntl(fd, fcntl.F_GETFL, 0) |
| flags = flags | os.O_NONBLOCK |
| fcntl.fcntl(fd, fcntl.F_SETFL, flags) |
| |
| def set_file(self, fd): |
| self.socket = file_wrapper(fd) |
| self._fileno = self.socket.fileno() |
| self.add_channel() |
