Password Checker.py

'''
Author : Zaheer Abbas
Description : This python script checks if your password has been pwned or not

This file contains three main functions.
1. main_file(filename)
-> Run this function if you have a lot of passwords stored in a file. You should give the filename as command line argument and also the file must be present in the same directory as you are currently running this python script on.
2. main_user_input()
-> Run this function if you want to manually provide the input. Note that this function has an infinite loop. To break out of this you must enter "-1"(without quotes).
3. main_command_line(args)
-> Run this function if you have a small number of passwords. You should give all the passwords that you want to check as command line arguments .

Uncomment any one of the function call(you can find those below at the bottom of the file) that you want to run and check if your password has been pwned or not securely

'''

import sys
import requests
import hashlib
import os


def request_api_data(first_5_char_hashed_password):
    '''requesting the data from the api'''
    url = "https://api.pwnedpasswords.com/range/" + first_5_char_hashed_password
    response = requests.get(url)
    if response.status_code != 200:
        raise RuntimeError(
            f"Error fetching the data, Response code : {response.status_code}. Check the api and try again later")
    return response


def check_my_password_pwned_count(response_from_api, our_hashed_password_suffix):
    '''Cheking if password has ever been pwned or hacked and returning the count'''
    password_tuple = (line.split(":")
                      for line in response_from_api.text.splitlines())
    for suffix, count in password_tuple:
        if suffix == our_hashed_password_suffix:
            return count
    return 0


def check_my_password(password):
    '''hashes the password and checks if the password is present in the api reponse'''
    sha1_hashed_password = hashlib.sha1(
        password.encode('utf-8')).hexdigest().upper()
    first_5_char = sha1_hashed_password[:5]
    suffix = sha1_hashed_password[5:]
    response = request_api_data(first_5_char)
    return check_my_password_pwned_count(response, suffix)


def main_file(filename):
    '''If you want to give file as input then call this function with the filename as command line argument. Note that the input file must be present in the same directory that you are currently running this script from'''
    absolute_path = os.path.abspath(filename)
    with open(absolute_path) as file:
        for password in file:
            password = password.strip()
            count = check_my_password(password)
            if count:
                print(
                    f"The password {password} has been seen {count} times... You should probably change your password!")
            else:
                print(
                    f"The password {password} has not been seen before... You can choose this password ")
    return "Done!"


def main_user_input():
    '''Call this function if you want to manually give the password as input'''
    while(True):
        print("Enter to \"-1\" Exit")
        print("Enter the password you want to check")
        try:
            password = input().strip()
        except:
            print("You must enter a string")
            continue
        if(password == "-1"):
            break
        count = check_my_password(password)
        if count:
            print(
                f"The password {password} has been seen {count} times... You should probably change your password!")
        else:
            print(
                f"The password {password} has not been seen before... You can choose this password ")
    return "Done!"


def main_command_line(args):
    ''' Call this function by giving multiple command line arguments'''
    for password in args:
        count = check_my_password(password)
        if count:
            print(
                f"The password {password} has been seen {count} times... You should probably change your password!")
        else:
            print(
                f"The password {password} has not been seen before... You can choose this password ")
    return "Done"


# main_file(sys.argv[1])

# main_user_input()

# main_command_line(sys.argv[1:])