Python PIPE to popen stdin

Question

I am attempting something very similar to real time subprocess.Popen via stdout and PIPE

I, however, want to send input to the running process as well.

If I

Answer 1

A simple portable solution in your case with minimal code changes might be to create a writer thread that get items from a queue and writes them to the process' stdin and then put values into the queue whenever the button is pressed:

from subprocess import Popen, PIPE, STDOUT
from Queue import Queue

class Example(Frame):
    def __init__(self, parent, queue):
       # ...
       self.queue = queue
    # ...
    def send(self): # should be call on the button press
        self.queue.put(prompt.get())

def writer(input_queue, output): 
    for item in iter(input_queue.get, None): # get items until None found
        output.write(item)
    output.close()

def MyThread(queue):
    # ...
    #NOTE: you must set `stdin=PIPE` if you wan't to write to process.stdin
    process = Popen(cmd, stdin=PIPE, stdout=PIPE, stderr=STDOUT)
    Thread(target=writer, args=[queue, process.stdin]).start()
    # ...

def main():
    # ...
    queue = Queue()
    app = Example(root, queue)
    Thread(target=MyThread, args=[queue]).start()
    # ...
    root.mainloop()
    queue.put(None) # no more input for the subprocess