IP Scanning program Python 3

Question

This is the code I made to scan IP addresses. I am new to python and just want to learn how I can optimize it. I know the subprocess is slower than others to IP scanning but if there is a way to make it faster I would like to know how. :)

#!/usr/bin/env python
# coding:utf-8
import subprocess
import datetime
hostname = input("Entrez la gateway de cette manière(example: 192.168.1)")
# Ask for gateway
while True:
 file_name = input("Comment voulez-vous appelez votre dossier?Sans espace ni caratère spéciaux(example:file_name)")
 # Ask how the user want to name the file where the result of the scan will be
 if " " in file_name:
 print("Réecrire le nom sans espace")
 # check for spaces in the name file(impossible to create name files with spaces or special characters)
 else:
 break
with open(str(file_name) + ".txt", "w")as i:
 i.write("Start time" + str(datetime.datetime.now()))
 # print the start time of the scan process
 for scan in range(1, 255):
 i.write("-" * 100)
 ip_address = str(hostname) + "." + str(scan)
 ping_response = subprocess.Popen(["ping", ip_address, "-n", '1'], stdout=subprocess.PIPE).stdout.read()
 #Ping the ip address
 ping_response = ping_response.decode()
 # (la réponse du ping est encoder , cette commande la decode)
 print("-"*100)
 print(ping_response)
 i.write(str(ping_response))
 if ip_address == hostname + "." + "254":
 i.write("End time" + str(datetime.datetime.now()))
 # print the end time of the scan process
 i.close()
 quit()

Answer 1

1. Use the argparse module for getting user input
2. Validate user input
3. Use f"{string}" or "{}".format(string) instead of manually concatting
4. No need to do i.close() as the with automatically closes the file
5. Use a if __name__ == '__main__' guard
6. Add functions for re usability

Revised Code

import subprocess
import datetime
import re
import argparse
def write_result(filename, ping):
 with open(filename, "w") as f:
 f.write(f"Start time {datetime.datetime.now()}")
 for result in ping:
 f.write(result)
 f.write(f"End time {datetime.datetime.now()}")
def ping_subnet(subnet):
 for addr in range(1, 255):
 yield subprocess.Popen(["ping", f"{subnet}.{addr}", "-n", "1"], stdout=subprocess.PIPE) \
 .stdout.read() \
 .decode()
def main(subnet, filename):
 write_result(filename, ping_subnet(subnet))
def parse_arguments():
 parser = argparse.ArgumentParser(usage='%(prog)s [options] <subnet>',
 description='ip checker',
 epilog="python ipscanner.py 192.168.1 -f somefile.txt")
 parser.add_argument('subnet', type=str, help='the subnet you want to ping')
 parser.add_argument('-f', '--filename', type=str, help='The filename')
 args = parser.parse_args()
 if not re.match(r"(\d{1,3}\.\d{1,3}\.\d{1,3})", args.subnet) \
 or any(a not in range(1, 255) for a in map(int, args.subnet.split("."))):
 parser.error("This is not a valid subnet")
 if " " in args.filename:
 parser.error("There cannot be whitespaces in the filename")
 return args.subnet, args.filename
if __name__ == '__main__':
 main(*parse_arguments())

• Thewizy: First thank you for the precious help! but where am I supposed to declare de subnet when i try to run the code i get this error:usage: labo3.py [options] <subnet> labo3.py: error: the following arguments are required: subnet
• Ludisposed: try python {scriptname} -h
• Ludisposed: Example usage would be python {scriptname} 192.168.1 -f somefile.txt
• Thewizy: Oh ok I understand now, (there's many things I've never used in your code I am going to learn how it works thank you!
• Ludisposed: Yeah my bad I didn't see the beginner tag, if you have any question feel free to ask them and I will answer as best as I can :)