def handle_request(self):
"""Handle one request, possibly blocking.
Respects self.timeout.
"""
# Support people who used socket.settimeout() to escape
# handle_request before self.timeout was available.
timeout = self.socket.gettimeout()
if timeout is None:
timeout = self.timeout
elif self.timeout is not None:
timeout = min(timeout, self.timeout)
fd_sets = select.select([self], [], [], timeout)
if not fd_sets[0]:
self.handle_timeout()
return
self._handle_request_noblock()
python类select()的实例源码
def _sendall(sock, data):
"""
Writes data to a socket and does not return until all the data is sent.
"""
length = len(data)
while length:
try:
sent = sock.send(data)
except socket.error, e:
if e[0] == errno.EAGAIN:
select.select([], [sock], [])
continue
else:
raise
data = data[sent:]
length -= sent
def recv(self, *args, **kwargs):
try:
data = self.connection.recv(*args, **kwargs)
except OpenSSL.SSL.SysCallError as e:
if self.suppress_ragged_eofs and e.args == (-1, 'Unexpected EOF'):
return b''
else:
raise SocketError(str(e))
except OpenSSL.SSL.ZeroReturnError as e:
if self.connection.get_shutdown() == OpenSSL.SSL.RECEIVED_SHUTDOWN:
return b''
else:
raise
except OpenSSL.SSL.WantReadError:
rd, wd, ed = select.select(
[self.socket], [], [], self.socket.gettimeout())
if not rd:
raise timeout('The read operation timed out')
else:
return self.recv(*args, **kwargs)
else:
return data
def recv_into(self, *args, **kwargs):
try:
return self.connection.recv_into(*args, **kwargs)
except OpenSSL.SSL.SysCallError as e:
if self.suppress_ragged_eofs and e.args == (-1, 'Unexpected EOF'):
return 0
else:
raise SocketError(str(e))
except OpenSSL.SSL.ZeroReturnError as e:
if self.connection.get_shutdown() == OpenSSL.SSL.RECEIVED_SHUTDOWN:
return 0
else:
raise
except OpenSSL.SSL.WantReadError:
rd, wd, ed = select.select(
[self.socket], [], [], self.socket.gettimeout())
if not rd:
raise timeout('The read operation timed out')
else:
return self.recv_into(*args, **kwargs)
def register(self, fileobj, events, data=None):
key = super(KqueueSelector, self).register(fileobj, events, data)
if events & EVENT_READ:
kevent = select.kevent(key.fd,
select.KQ_FILTER_READ,
select.KQ_EV_ADD)
_syscall_wrapper(self._kqueue.control, False, [kevent], 0, 0)
if events & EVENT_WRITE:
kevent = select.kevent(key.fd,
select.KQ_FILTER_WRITE,
select.KQ_EV_ADD)
_syscall_wrapper(self._kqueue.control, False, [kevent], 0, 0)
return key
def unregister(self, fileobj):
key = super(KqueueSelector, self).unregister(fileobj)
if key.events & EVENT_READ:
kevent = select.kevent(key.fd,
select.KQ_FILTER_READ,
select.KQ_EV_DELETE)
try:
_syscall_wrapper(self._kqueue.control, False, [kevent], 0, 0)
except SelectorError:
pass
if key.events & EVENT_WRITE:
kevent = select.kevent(key.fd,
select.KQ_FILTER_WRITE,
select.KQ_EV_DELETE)
try:
_syscall_wrapper(self._kqueue.control, False, [kevent], 0, 0)
except SelectorError:
pass
return key
def recv(self, *args, **kwargs):
try:
data = self.connection.recv(*args, **kwargs)
except OpenSSL.SSL.SysCallError as e:
if self.suppress_ragged_eofs and e.args == (-1, 'Unexpected EOF'):
return b''
else:
raise SocketError(str(e))
except OpenSSL.SSL.ZeroReturnError as e:
if self.connection.get_shutdown() == OpenSSL.SSL.RECEIVED_SHUTDOWN:
return b''
else:
raise
except OpenSSL.SSL.WantReadError:
rd, wd, ed = select.select(
[self.socket], [], [], self.socket.gettimeout())
if not rd:
raise timeout('The read operation timed out')
else:
return self.recv(*args, **kwargs)
else:
return data
def recv_into(self, *args, **kwargs):
try:
return self.connection.recv_into(*args, **kwargs)
except OpenSSL.SSL.SysCallError as e:
if self.suppress_ragged_eofs and e.args == (-1, 'Unexpected EOF'):
return 0
else:
raise SocketError(str(e))
except OpenSSL.SSL.ZeroReturnError as e:
if self.connection.get_shutdown() == OpenSSL.SSL.RECEIVED_SHUTDOWN:
return 0
else:
raise
except OpenSSL.SSL.WantReadError:
rd, wd, ed = select.select(
[self.socket], [], [], self.socket.gettimeout())
if not rd:
raise timeout('The read operation timed out')
else:
return self.recv_into(*args, **kwargs)
def serve_forever(self, poll_interval=0.5):
"""Handle one request at a time until shutdown.
Polls for shutdown every poll_interval seconds. Ignores
self.timeout. If you need to do periodic tasks, do them in
another thread.
"""
self.__is_shut_down.clear()
try:
while not self.__shutdown_request:
# XXX: Consider using another file descriptor or
# connecting to the socket to wake this up instead of
# polling. Polling reduces our responsiveness to a
# shutdown request and wastes cpu at all other times.
r, w, e = select.select([self], [], [], poll_interval)
if self in r:
self._handle_request_noblock()
finally:
self.__shutdown_request = False
self.__is_shut_down.set()
def shutdown(self):
"""Stops the serve_forever loop.
Blocks until the loop has finished. This must be called while
serve_forever() is running in another thread, or it will
deadlock.
"""
self.__shutdown_request = True
self.__is_shut_down.wait()
# The distinction between handling, getting, processing and
# finishing a request is fairly arbitrary. Remember:
#
# - handle_request() is the top-level call. It calls
# select, get_request(), verify_request() and process_request()
# - get_request() is different for stream or datagram sockets
# - process_request() is the place that may fork a new process
# or create a new thread to finish the request
# - finish_request() instantiates the request handler class;
# this constructor will handle the request all by itself
def _handle_request_noblock(self):
"""Handle one request, without blocking.
I assume that select.select has returned that the socket is
readable before this function was called, so there should be
no risk of blocking in get_request().
"""
try:
request, client_address = self.get_request()
except socket.error:
return
if self.verify_request(request, client_address):
try:
self.process_request(request, client_address)
except:
self.handle_error(request, client_address)
self.shutdown_request(request)
def interact(self):
"""Interaction function, emulates a very dumb telnet client."""
if sys.platform == "win32":
self.mt_interact()
return
while 1:
rfd, wfd, xfd = select.select([self, sys.stdin], [], [])
if self in rfd:
try:
text = self.read_eager()
except EOFError:
print '*** Connection closed by remote host ***'
break
if text:
sys.stdout.write(text)
sys.stdout.flush()
if sys.stdin in rfd:
line = sys.stdin.readline()
if not line:
break
self.write(line)
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 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
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 register(self, fileobj, events, data=None):
key = super(KqueueSelector, self).register(fileobj, events, data)
if events & EVENT_READ:
kevent = select.kevent(key.fd,
select.KQ_FILTER_READ,
select.KQ_EV_ADD)
_syscall_wrapper(self._kqueue.control, False, [kevent], 0, 0)
if events & EVENT_WRITE:
kevent = select.kevent(key.fd,
select.KQ_FILTER_WRITE,
select.KQ_EV_ADD)
_syscall_wrapper(self._kqueue.control, False, [kevent], 0, 0)
return key
def unregister(self, fileobj):
key = super(KqueueSelector, self).unregister(fileobj)
if key.events & EVENT_READ:
kevent = select.kevent(key.fd,
select.KQ_FILTER_READ,
select.KQ_EV_DELETE)
try:
_syscall_wrapper(self._kqueue.control, False, [kevent], 0, 0)
except SelectorError:
pass
if key.events & EVENT_WRITE:
kevent = select.kevent(key.fd,
select.KQ_FILTER_WRITE,
select.KQ_EV_DELETE)
try:
_syscall_wrapper(self._kqueue.control, False, [kevent], 0, 0)
except SelectorError:
pass
return key
def DefaultSelector():
""" This function serves as a first call for DefaultSelector to
detect if the select module is being monkey-patched incorrectly
by eventlet, greenlet, and preserve proper behavior. """
global _DEFAULT_SELECTOR
if _DEFAULT_SELECTOR is None:
if _can_allocate('kqueue'):
_DEFAULT_SELECTOR = KqueueSelector
elif _can_allocate('epoll'):
_DEFAULT_SELECTOR = EpollSelector
elif _can_allocate('poll'):
_DEFAULT_SELECTOR = PollSelector
elif hasattr(select, 'select'):
_DEFAULT_SELECTOR = SelectSelector
else: # Platform-specific: AppEngine
raise ValueError('Platform does not have a selector')
return _DEFAULT_SELECTOR()
def register(self, fileobj, events, data=None):
key = super(KqueueSelector, self).register(fileobj, events, data)
if events & EVENT_READ:
kevent = select.kevent(key.fd,
select.KQ_FILTER_READ,
select.KQ_EV_ADD)
_syscall_wrapper(self._kqueue.control, False, [kevent], 0, 0)
if events & EVENT_WRITE:
kevent = select.kevent(key.fd,
select.KQ_FILTER_WRITE,
select.KQ_EV_ADD)
_syscall_wrapper(self._kqueue.control, False, [kevent], 0, 0)
return key
def unregister(self, fileobj):
key = super(KqueueSelector, self).unregister(fileobj)
if key.events & EVENT_READ:
kevent = select.kevent(key.fd,
select.KQ_FILTER_READ,
select.KQ_EV_DELETE)
try:
_syscall_wrapper(self._kqueue.control, False, [kevent], 0, 0)
except SelectorError:
pass
if key.events & EVENT_WRITE:
kevent = select.kevent(key.fd,
select.KQ_FILTER_WRITE,
select.KQ_EV_DELETE)
try:
_syscall_wrapper(self._kqueue.control, False, [kevent], 0, 0)
except SelectorError:
pass
return key
def DefaultSelector():
""" This function serves as a first call for DefaultSelector to
detect if the select module is being monkey-patched incorrectly
by eventlet, greenlet, and preserve proper behavior. """
global _DEFAULT_SELECTOR
if _DEFAULT_SELECTOR is None:
if _can_allocate('kqueue'):
_DEFAULT_SELECTOR = KqueueSelector
elif _can_allocate('epoll'):
_DEFAULT_SELECTOR = EpollSelector
elif _can_allocate('poll'):
_DEFAULT_SELECTOR = PollSelector
elif hasattr(select, 'select'):
_DEFAULT_SELECTOR = SelectSelector
else: # Platform-specific: AppEngine
raise ValueError('Platform does not have a selector')
return _DEFAULT_SELECTOR()
def _recv(self, which, maxsize):
conn, maxsize = self.get_conn_maxsize(which, maxsize)
if conn is None:
return None
if not select.select([conn], [], [], 0)[0]:
return ''
r = conn.read(maxsize)
if not r:
return self._close(which)
if self.universal_newlines:
r = r.replace("\r\n", "\n").replace("\r", "\n")
return r
################################################################################
def _recvall(sock, length):
"""
Attempts to receive length bytes from a socket, blocking if necessary.
(Socket may be blocking or non-blocking.)
"""
dataList = []
recvLen = 0
while length:
try:
data = sock.recv(length)
except socket.error, e:
if e[0] == errno.EAGAIN:
select.select([sock], [], [])
continue
else:
raise
if not data: # EOF
break
dataList.append(data)
dataLen = len(data)
recvLen += dataLen
length -= dataLen
return ''.join(dataList), recvLen
def recvall(sock, length):
"""
Attempts to receive length bytes from a socket, blocking if necessary.
(Socket may be blocking or non-blocking.)
"""
dataList = []
recvLen = 0
while length:
try:
data = sock.recv(length)
except socket.error, e:
if e[0] == errno.EAGAIN:
select.select([sock], [], [])
continue
else:
raise
if not data: # EOF
break
dataList.append(data)
dataLen = len(data)
recvLen += dataLen
length -= dataLen
return ''.join(dataList), recvLen
def _recvall(sock, length):
"""
Attempts to receive length bytes from a socket, blocking if necessary.
(Socket may be blocking or non-blocking.)
"""
dataList = []
recvLen = 0
while length:
try:
data = sock.recv(length)
except socket.error, e:
if e[0] == errno.EAGAIN:
select.select([sock], [], [])
continue
else:
raise
if not data: # EOF
break
dataList.append(data)
dataLen = len(data)
recvLen += dataLen
length -= dataLen
return ''.join(dataList), recvLen
def _sendall(sock, data):
"""
Writes data to a socket and does not return until all the data is sent.
"""
length = len(data)
while length:
try:
sent = sock.send(data)
except socket.error, e:
if e[0] == errno.EAGAIN:
select.select([], [sock], [])
continue
else:
raise
data = data[sent:]
length -= sent
def processInput(self):
"""Wait for and process a single packet."""
pkt = Packet()
select.select([self._sock], [], [])
pkt.read(self._sock)
# Body chunks have no packet type code.
if self._request is not None:
self._processBody(pkt)
return
if not pkt.length:
raise ProtocolError, 'unexpected empty packet'
pkttype = pkt.data[0]
if pkttype == PKTTYPE_FWD_REQ:
self._forwardRequest(pkt)
elif pkttype == PKTTYPE_SHUTDOWN:
self._shutdown(pkt)
elif pkttype == PKTTYPE_PING:
self._ping(pkt)
elif pkttype == PKTTYPE_CPING:
self._cping(pkt)
else:
raise ProtocolError, 'unknown packet type'
def _recvall(sock, length):
"""
Attempts to receive length bytes from a socket, blocking if necessary.
(Socket may be blocking or non-blocking.)
"""
dataList = []
recvLen = 0
while length:
try:
data = sock.recv(length)
except socket.error, e:
if e[0] == errno.EAGAIN:
select.select([sock], [], [])
continue
else:
raise
if not data: # EOF
break
dataList.append(data)
dataLen = len(data)
recvLen += dataLen
length -= dataLen
return ''.join(dataList), recvLen
def _sendall(sock, data):
"""
Writes data to a socket and does not return until all the data is sent.
"""
length = len(data)
while length:
try:
sent = sock.send(data)
except socket.error, e:
if e[0] == errno.EAGAIN:
select.select([], [sock], [])
continue
else:
raise
data = data[sent:]
length -= sent
def register(self, fileobj, events, data=None):
key = super(KqueueSelector, self).register(fileobj, events, data)
if events & EVENT_READ:
kevent = select.kevent(key.fd,
select.KQ_FILTER_READ,
select.KQ_EV_ADD)
_syscall_wrapper(self._kqueue.control, False, [kevent], 0, 0)
if events & EVENT_WRITE:
kevent = select.kevent(key.fd,
select.KQ_FILTER_WRITE,
select.KQ_EV_ADD)
_syscall_wrapper(self._kqueue.control, False, [kevent], 0, 0)
return key
