How to determine from a python application if X server/X forwarding is running?
Check to see that the $DISPLAY
environment variable is set - if they didn't use ssh -X
, it will be empty (instead of containing something like localhost:10
).
As mentioned before, you can check the DISPLAY environment variable:
>>> os.environ['DISPLAY']
'localhost:10.0'
If you're so inclined, you could actually connect to the display port to see that sshd is listening on it:
import os
import socket
def tcp_connect_to_display():
# get the display from the environment
display_env = os.environ['DISPLAY']
# parse the display string
display_host, display_num = display_env.split(':')
display_num_major, display_num_minor = display_num.split('.')
# calculate the port number
display_port = 6000 + int(display_num_major)
# attempt a TCP connection
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
try:
sock.connect((display_host, display_port))
except socket.error:
return False
finally:
sock.close()
return True
This relies on standard X configuration using ports 6000 + display number.
Similar to your xclock solution, I like to run xdpyinfo and see if it returns an error.