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POproblem printing mount point of usb in python
 

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  1. POproblem printing mount point of usb in python
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    <p>I have a program written in python that uses dbus to detect inserted usb drives and prints the dir they are mounted on when they are detected. Here is the code:</p> <pre> import dbus import gobject import shutil import os import subprocess import time class DeviceAddedListener: def __init__(self): self.bus = dbus.SystemBus() self.hal_manager_obj = self.bus.get_object( "org.freedesktop.Hal", "/org/freedesktop/Hal/Manager") self.hal_manager = dbus.Interface(self.hal_manager_obj, "org.freedesktop.Hal.Manager") self.hal_manager.connect_to_signal("DeviceAdded", self._filter) def _filter(self, udi): device_obj = self.bus.get_object ("org.freedesktop.Hal", udi) device = dbus.Interface(device_obj, "org.freedesktop.Hal.Device") if device.QueryCapability("volume"): return self.do_something(device) def do_something(self, volume): device_file = volume.GetProperty("block.device") label = volume.GetProperty("volume.label") fstype = volume.GetProperty("volume.fstype") mounted = volume.GetProperty("volume.is_mounted") mount_point = volume.GetProperty("volume.mount_point") try: size = volume.GetProperty("volume.size") except: size = 0 p1 = subprocess.Popen(["df", "-h"], stdout=subprocess.PIPE) p2 = subprocess.Popen(["grep", device_file], stdin=p1.stdout, stdout=subprocess.PIPE) p3 = subprocess.Popen(["awk", "{ print $6 }"], stdin=p2.stdout, stdout=subprocess.PIPE) path = p3.communicate()[0] print path if __name__ == '__main__': from dbus.mainloop.glib import DBusGMainLoop DBusGMainLoop(set_as_default=True) loop = gobject.MainLoop() DeviceAddedListener() loop.run() </pre> <p>The problem is that when I print the path variable (the mount point of the usb), it prints an empty string. However, when I execute these same commands (Popen(), etc) in the python interactive interpreter, it prints the path just fine (/media/03CB-604C). Why does this occur? Any edits / suggestions to my code would be much appreciated. Thanks in advance!</p>
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    1. USJake Burchard
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      1. VTUpMod
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    1. COAre the "p1... p2... lines indented wrong? Are they part of "do_something"?
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      1. POproblem printing mount point of usb in python
      1. USmjhm
    2. COAllow me to make a suggestion -- doing this through dbus is far less efficient then if you did it through inotify (a kernel extension). If you have the option to build it in (or it'ds built in already), you can just watch the mount directory. http://pyinotify.sourceforge.net/ Also, there's no need to subprocess df/grep/awk -- what you want is in /proc/diskstats and can be extracted with a few lines of native python.
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      1. POproblem printing mount point of usb in python
      1. USsynthesizerpatel
    3. CO@mjhm, yeah sorry about the poor indentation: in my actual code they are part of do_something, but when I transferred it to stack overflow the indentation got messed up.
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      1. POproblem printing mount point of usb in python
      1. USJake Burchard
 

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