# -*- 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 "morethan one thing at a time".  Multi-threaded programming is the simplest andmost popular way to do it, but there is another very different technique,that lets you have nearly all the advantages of multi-threading, withoutactually using multiple threads. it's really only practical if your programis largely I/O bound. If your program is CPU bound, then pre-emptivescheduled threads are probably what you really need. Network servers arerarely CPU-bound, however. If your operating system supports the select() system call in its I/Olibrary (and nearly all do), then you can use it to juggle multiplecommunication channels at once; doing other work while your I/O is takingplace in the "background."  Although this strategy can seem strange andcomplex, especially at first, it is in many ways easier to understand andcontrol than multi-threaded programming. The module documented here solvesmany of the difficult problems for you, making the task of buildingsophisticated high-performance network servers and clients a snap.""" import selectimport socketimport sysimport time import osfrom errno import EALREADY, EINPROGRESS, EWOULDBLOCK, ECONNRESET, \     ENOTCONN, ESHUTDOWN, EINTR, EISCONN, errorcode try:    socket_mapexcept NameError:    socket_map = {} class ExitNow(Exception):    pass def read(obj):    try:        obj.handle_read_event()    except ExitNow:        raise    except:        obj.handle_error() def write(obj):    try:        obj.handle_write_event()    except ExitNow:        raise    except:        obj.handle_error() def _exception (obj):    try:        obj.handle_expt_event()    except ExitNow:        raise    except:        obj.handle_error() def readwrite(obj, flags):    try:        if flags & (select.POLLIN | select.POLLPRI):            obj.handle_read_event()        if flags & select.POLLOUT:            obj.handle_write_event()        if flags & (select.POLLERR | select.POLLHUP | select.POLLNVAL):            obj.handle_expt_event()    except ExitNow:        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)            if is_w:                w.append(fd)            if is_r or is_w:                e.append(fd)        if [] == r == w == e:            time.sleep(timeout)        else:            try:                r, w, e = select.select(r, w, e, timeout)            except select.error, err:                if err[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            if obj.writable():                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[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    closing = False    addr = None     def __init__(self, sock=None, map=None):        if map is None:            self._map = socket_map        else:            self._map = map         if sock:            self.set_socket(sock, map)            # I think it should inherit this anyway            self.socket.setblocking(0)            self.connected = True            # XXX Does the constructor require that the socket passed            # be connected?            try:                self.addr = sock.getpeername()            except socket.error:                # The addr isn't crucial                pass        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))     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 map.has_key(fd):            #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        self.socket = socket.socket(family, type)        self.socket.setblocking(0)        self._fileno = self.socket.fileno()        self.add_channel()     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 = 1        return self.socket.listen(num)     def bind(self, addr):        self.addr = addr        return self.socket.bind(addr)     def connect(self, address):        self.connected = False        err = self.socket.connect_ex(address)        # XXX Should interpret Winsock return values        if err in (EINPROGRESS, EALREADY, EWOULDBLOCK):            return        if err in (0, EISCONN):            self.addr = address            self.connected = True            self.handle_connect()        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()            return conn, addr        except socket.error, why:            if why[0] == EWOULDBLOCK:                pass            else:                raise     def send(self, data):        try:            result = self.socket.send(data)            return result        except socket.error, why:            if why[0] == EWOULDBLOCK:                return 0            else:                raise            return 0     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 throws ENOTCONN            if why[0] in [ECONNRESET, ENOTCONN, ESHUTDOWN]:                self.handle_close()                return ''            else:                raise     def close(self):        self.del_channel()        self.socket.close()     # cheap inheritance, used to pass all other attribute    # references to the underlying socket object.    def __getattr__(self, attr):        return getattr(self.socket, attr)     # 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 __debug__ or type != 'info':            print '%s: %s' % (type, message)     def handle_read_event(self):        if self.accepting:            # for an accepting socket, getting a read implies            # that we are connected            if not self.connected:                self.connected = True            self.handle_accept()        elif not self.connected:            self.handle_connect()            self.connected = True            self.handle_read()        else:            self.handle_read()     def handle_write_event(self):        # getting a write implies that we are connected        if not self.connected:            self.handle_connect()            self.connected = True        self.handle_write()     def handle_expt_event(self):        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.close()     def handle_expt(self):        self.log_info('unhandled exception', '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 = []    assert tb # Must have a traceback    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):    if map is None:        map = socket_map    for x in map.values():        x.socket.close()    map.clear() # Asynchronous File I/O:#

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