出于测试目的,我已经使用gevent.StreamServer编写了一个简单的tcp服务器。为了让我向一些客户端发送响应,我需要一种非阻塞的方式来处理通过raw_input()的输入,最好不要使用线程。
在谷歌了一下之后,我偶然发现了这个问题:How to make non-blocking raw_input when using eventlet.monkey_patch() and why it block everything, even when executed on another thread?
我已经写了下面的代码,它做的正是我想要的,不过我假设有更好的方法。谁能给我指个方向?此外,我们也希望了解一下为什么try/except不能捕获KeyboardInterrupt。
import select
from gevent.monkey import patch_all
from gevent.server import StreamServer
patch_all(os=True, select=True)
def raw_input(message):
""" Non-blocking input from stdin. """
sys.stdout.write(message)
select.select([sys.stdin], [], [])
return sys.stdin.readline()
def main():
""" Run the server, listen for commands """
server = StreamServer(("0.0.0.0", 6000), handle)
print "Starting server"
gevent.signal(signal.SIGTERM, server.close)
gevent.signal(signal.SIGQUIT, server.close)
gevent.signal(signal.SIGINT, server.close)
server.start()
while True:
try:
a = raw_input("")
if a:
print "Received %s" % a
gevent.sleep(0)
except KeyboardInterrupt:
print "Received a shutdown signal, going down ..."
server.stop()
sys.exit(0)
if __name__ == "__main__":
main()编辑:我重写了部分代码,现在我明白了main()-function的愚蠢之处。我会将其作为编辑后发布,以防有人偶然发现这个问题,并对如何做有更好的想法。
from gevent.signal import signal
def get_console_input():
""" Non-blocking console input to the server """
select.select([sys.stdin], [], [])
# There's quite a bit of code here but it is input handling so
# for shortness's sake I've snipped everything and return the line read.
return sys.stdin.readline()
def exit(server):
""" Quit the server gracefully """
print "Received shutdown signal, going down. """
server.close()
sys.exit(0)
def main():
""" The main function. Create and run the server, listen for commands and
append any command to the server so it can send them on to the clients """
# Myserver is a class which inherits from gevent.server.StreamServer.
# Myserver could just as well be replaced by gevent.server.StreamServer.
server = MyServer(("0.0.0.0", PORT))
print "Starting server"
# Add some signal handlers to quit the server gracefully.
gevent.signal(signal.SIGTERM, exit, server)
gevent.signal(signal.SIGQUIT, exit, server)
gevent.signal(signal.SIGINT, exit, server)
# Server started in async mode
server.start()
while True:
get_console_input()
gevent.sleep(0)
if __name__ == "__main__":
main()发布于 2012-06-12 15:27:24
我找到的最简单的方法是使用gevent.socket.wait_read等待,直到可以读取sys.stdin:
wait_read(sys.stdin.fileno())
return sys.stdin.readline()我还编写了一个围绕文件描述符的小包装器,为它们提供非阻塞的.read()和.write()方法:https://gist.github.com/2915875
https://stackoverflow.com/questions/10601382
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