This is a follow-up question on handling the data in the socket. However, I am unable to capture the "stdin closed" event. Here's what I have now:
import sys
import tornado
from tornado.ioloop import IOLoop
from tornado.web import Application, RequestHandler
class MainHandler(RequestHandler):
def get(self):
self.finish("foo")
application = Application([ (r"/", MainHandler), ])
@tornado.gen.coroutine
def close_callback(*args, **kwargs):
print args, kwargs
if __name__ == "__main__":
application.listen(8888)
stdin = tornado.iostream.PipeIOStream(sys.stdin.fileno())
stdin.set_close_callback(close_callback)
IOLoop.instance().start()
And a test:
$ ./tornado_sockets.py # expect to close stdin
<C-d> # nothing happens
Another test:
$ echo expect_stdin_to_be_closed | ./tornado_sockets.py
# nothing happens
How can I listen for closing of stdin?
Quote sys.stdin does not close on ctrl-d:
Ctrl+D has a strange effect. It doesn't close the input stream, but only causes a C-level fread() to return an empty result.
So basically you need to assert read line with empty string. Some example without PipeIOStream
:
from tornado.ioloop import IOLoop
import sys
def on_stdin(fd, events):
line = fd.readline()
print("received: %s" % repr(line))
if line == '':
print('stdin ctr+d')
sys.exit()
if __name__ == "__main__":
IOLoop.instance().add_handler(sys.stdin, on_stdin, IOLoop.READ)
IOLoop.instance().start()
With PipeIOStream
it is pretty straightforward using read_until_close
. Callback will be called on close or on Ctrl+D.
import sys
import tornado
import tornado.iostream
from tornado.ioloop import IOLoop
from functools import partial
def read(stdin, data):
print(data)
# below lines are unnecessary they are only for testing purposes
stdin.close()
IOLoop.instance().stop()
if __name__ == "__main__":
stdin = tornado.iostream.PipeIOStream(sys.stdin.fileno())
stdin.read_until_close(callback=partial(read, stdin))
IOLoop.instance().start()