online compiler这是我的网站，用户可以在其中运行控制台程序。
目前，用户在运行程序之前必须输入程序输入。我正在尝试为该程序构建实时用户输入(希望提供与他们在笔记本电脑上运行程序相同的体验)。
在实现这一目标的研究中，我遇到了使用 websocket 来stream stdout and stdin 的解决方案。
我的实现
# coding: utf-8
import subprocess
import thread
from tornado.websocket import WebSocketHandler
from nbstreamreader import NonBlockingStreamReader as NBSR
class WSHandler(WebSocketHandler):
def open(self):
self.write_message("connected")
self.app = subprocess.Popen(['sh', 'app/shell.sh'], stdout=subprocess.PIPE, stdin=subprocess.PIPE,
shell=False)
self.nbsr = NBSR(self.app.stdout)
thread.start_new_thread(self.soutput, ())
def on_message(self, incoming):
self.app.stdin.write(incoming)
def on_close(self):
self.write_message("disconnected")
def soutput(self):
while True:
output = self.nbsr.readline(0.1)
# 0.1 secs to let the shell output the result
if not output:
print 'No more data'
break
self.write_message(output)
nbstreamreader.py
from threading import Thread
from Queue import Queue, Empty
class NonBlockingStreamReader:
def __init__(self, stream):
'''
stream: the stream to read from.
Usually a process' stdout or stderr.
'''
self._s = stream
self._q = Queue()
def _populateQueue(stream, queue):
'''
Collect lines from 'stream' and put them in 'quque'.
'''
while True:
line = stream.readline()
if line:
queue.put(line)
else:
raise UnexpectedEndOfStream
self._t = Thread(target=_populateQueue,
args=(self._s, self._q))
self._t.daemon = True
self._t.start() # start collecting lines from the stream
def readline(self, timeout=None):
try:
return self._q.get(block=timeout is not None,
timeout=timeout)
except Empty:
return None
class UnexpectedEndOfStream(Exception): pass
shell.sh
#!/usr/bin/env bash
echo "hello world"
echo "hello world"
read -p "Your first name: " fname
read -p "Your last name: " lname
echo "Hello $fname $lname ! I am learning how to create shell scripts"
此代码流式传输 stdout 直到 shell.sh 代码到达读取语句。
请指导我做错了什么。为什么它不等待 stdin 并在程序执行完成之前打印“No more data”？
请您参考如下方法:
您的 readline() 方法超时，除非您在 100 毫秒内发送输入，然后中断循环。您看不到 read -p 提示的原因是缓冲(因为 readline 和管道缓冲)。最后，您的示例 javascript 不会发送尾随换行符，因此 read 不会返回。
如果增加超时，包括一个换行符和find a way to work around buffering issues ，您的示例基本上应该有效。
我也会使用 tornado.process和协程而不是子进程和线程:
from tornado import gen
from tornado.process import Subprocess
from tornado.ioloop import IOLoop
from tornado.iostream import StreamClosedError
from tornado.websocket import WebSocketHandler
class WSHandler(WebSocketHandler):
def open(self):
self.app = Subprocess(['script', '-q', 'sh', 'app/shell.sh'], stdout=Subprocess.STREAM, stdin=Subprocess.STREAM)
IOLoop.current().spawn_callback(self.stream_output)
def on_message(self, incoming):
self.app.stdin.write(incoming.encode('utf-8'))
@gen.coroutine
def stream_output(self):
try:
while True:
line = yield self.app.stdout.read_bytes(1000, partial=True)
self.write_message(line.decode('utf-8'))
except StreamClosedError:
pass
