Basic request script

Question

I've just recently started running some wargames (Natas, OverTheWire) and thought I'd implement some of my scripting experience to solve them instead of doing it manually (though I did that first).

I've got this script:

import requests
from requests.auth import HTTPBasicAuth

def exploit(host, credentials):
    print(host)
    try:

        r = requests.get(host,
                         auth=HTTPBasicAuth(credentials[0],
                                            credentials[1]),
                         headers={'referer': 'http://natas5.natas.labs.overthewire.org/'}
                         )

        print([line for line in r.content.decode('ascii').split('\n') \
               if 'natas5' in line][0])

    except Exception as e:
        print(e)

def main():
    host = 'http://natas4.natas.labs.overthewire.org'
    credentials = ('natas4', 'Z9tkRkWmpt9Qr7XrR5jWRkgOU901swEZ')
    exploit(host, credentials)

if __name__ == '__main__':
    main()

I know it's a really basic script, but I'd really want to know if I'm following the right coding conventions and if there are ways of making a bit better. I've rarely used the requests library, so I'm still fairly new to it.

Answer 1

I would start with the following improvements:

• better naming - for instance, r is not a good variable name. Remember that code is much more often read than written
• avoid hardcoding constants - define them as proper Python constants (these are not really constants, but more like a guideline)
• you can use next() built-in function instead of a list comprehension and then getting the first filtered item
• you can unpack the credentials tuple into the HTTPBasicAuth arguments
• avoid having a bare except clause - catch more specific exceptions if needed

Improved code:

import requests
from requests.auth import HTTPBasicAuth


REFERER = 'http://natas5.natas.labs.overthewire.org/'
KEYWORD = 'natas5'


def exploit(host, credentials):
    """TODO: docstring here"""
    try:
        response = requests.get(host,
                                auth=HTTPBasicAuth(*credentials),
                                headers={'referer': REFERER})

        response_lines = response.content.decode('ascii').split('\n')
        return next((line for line in response_lines if KEYWORD in line), 'Keyword not found')
    except requests.RequestException as e:
        print(e)


def main():
    host = 'http://natas4.natas.labs.overthewire.org'
    credentials = ('natas4', 'Z9tkRkWmpt9Qr7XrR5jWRkgOU901swEZ')
    print(exploit(host, credentials))


if __name__ == '__main__':
    main()