Hey Steve,
Well, I've tried flush() before, but I didn't know about the "-u" switch.
Thank you for tinkering on this, I shall post again if I make any progress.
Avi
Steve Holden wrote:
Steve Holden wrote:
Avi Berkovich wrote:
Hey,
I can't make it work, I don't get any data from either stdout nor stderr.
If I send lines and then close the stdin pipe, I may get an exception message from several lines up.
I tried manually reading from the stdout pipe, but it just blocks and hangs no matter what I send over via the stdin pipe.
This behavior isn't presented by the command line interpreter by any chance.
Any suggestions?
Yes: post your code along with messages (if any)!
regards Steve
Sorry, for some reason I can no longer find the message you posted the code in -- it didn't get correctly threaded in Mozilla. Anyway, I can't say that I exactly understand what's going on, but here are a couple of observations:
1. The interpreter performs buffering even when running in interactive mode unless it can see a terminal (which here it can't). Hence adding a "-u" to the interpreter command line is useful.
2. There's a problem with your stop condition, which is why the attached modified version sleeps before closing the pipe to the interpreter.
import threading import sys import popen2
class Piper(threading.Thread):
def __init__(self, readPipe, output): threading.Thread.__init__(self)
if not isinstance(readPipe, file): raise TypeError, "readPipe parameter must be of File type" #if not isinstance(output, file): # raise TypeError, "output parameter must be of File type"
self.readPipe = readPipe self.output = output self.toStop = False
def run(self): print "Running" while not self.toStop and not self.readPipe.closed: read = self.readPipe.readline() self.output.write(read) self.output.flush() print "Stopped"
def stop(self): self.toStop = True
if __name__ == "__main__": r, w = popen2.popen4('c:\\python24\\python.exe -u') piper = Piper(r, sys.stdout) piper.start() w.write("print 'Hello!'\r\n") w.flush() w.write("print 'Goodbye!'\r\n") w.flush() import time; time.sleep(2) w.close() #import time; time.sleep(3) #r.close() piper.stop()
Various other bits and pieces of messing about didn't really yield any useful conclusions, so I pass this on only in the hope that you may be more motivated to follow up now you can actually see some interpreter output. I would have thought the flush() calls would have made output appear one line at a time, but sadly they do not.
regards Steve
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