How to ping a device in python?

[ofe]

Hello
I have my raspberry that controls (will control) a drone.
An additional devide (a pc , for instance) connected via wifi on teh same network, sends the commands to rpi.

I need to detect if raspberry loose connection to the device.

I can image to develop a "ping" funcion.
Can you suggest me some available library or giv eme some example?

It is mandatory that this chack has not to lock the main loop (eventually I can think to make a parallel thread).

BR
Oscar

[paddyg]

Not entirely what's pinging what but if you can run python on both then this would be quite easy. google things like 'python simple socket' or 'python simple server'

[ofe]

Hi,
Image that in the rpi I have a webserver,
that I would like to connect from any device ( my pc, or a smartphone via browser).
So I would not limitate the connection check respect a specific socket connection.

O.

[paddyg]

Flask is a good place to start. I'm doing a project now for google devart and flask proved to very easy to set up and use.

[Nander]

The easiest way would be to use the python subprocess library and call ping itself and read the output. And if you need it run parallel you can use the threading library. Simple example, ping and return the value of packets received.

Code: Select all

import subprocess
subprocess.call("ping 8.8.8.8 -c 1 | grep 'received' | awk -F',' '{ print $2}' | awk '{ print $1}'", shell=True)

In this case it pings the google dns server once and prints out the response. Change the ip and packet nr to anything you want.

*Borrowed the code from cyberciti

[aplocher]

I realize this is an old thread, but just thought I would contribute a little.

@Nander: Doing string checks (the word "received" in your example) is always a concern for me. I worry that 'ping' might have different language variants that will cause it to break on other systems. Also when I run your code, I get back two lines:

Success:
1
0

or, Fail:
0
0

Plus, I believe Shell=True should be avoided (whenever possible). Here's an alternative that won't rely on a string result and will not require Shell=True:

Code: Select all

import subprocess
res = subprocess.call(["ping", "8.8.8.8", "-c1", "-W2", "-q"])
print(res)

"res" should be based on the exit code from ping. success: =0, fail: >0

Something like this should suppress the output, too:

Code: Select all

res = subprocess.call(["ping", "8.8.8.8", "-c1", "-W2", "-q"], stdout=open(os.devnull,'w'))

[Errorplayer]

Hello
just to add:

I tried both codes sugested above.
this one

import subprocess
subprocess.call("ping 8.8.8.8 -c 1 | grep 'received' | awk -F',' '{ print $2}' | awk '{ print $1}'", shell=True)

just gives me as an output 127. Even when i am diconnected.
and the other one:

import subprocess
res = subprocess.call(["ping", "8.8.8.8", "-c1", "-W2", "-q"])
print(res)

did work in Shell but not in Thonny.
In thonny i did not get an output.
With

import subprocess
res = subprocess.call(["ping", "8.8.8.8", "-c1", "-W2", "-q"], stdout=open(devnull, 'w'))
print(res)

it worked perfectl in Thonny.

So use the second code.