Creating a Domain Availability Checker

Posted on 17 August 2019 in code kata

I was looking for some short domains I can use for my project. I went to a domain registrar and used their search tool to find a random combination of 2 letters domains. You can imagine how tedious this can be so I thought of a way to check all possible character combinations.

I created a python script that takes four variables:

• Smallest size of characters combination
• Largest size of characters combination
• The characters to use
• The TLDs to check

The script takes the first three variables and creates a list of combinations. It then removes any duplicate and sort them alphabetically.

It then loop through the TLDs and character combination list and push them through an availability checker. In this case I simply used a whois check. The script is buggy right now and sometimes return false answers. I could’ve used a third party API to improve the result but for now, this will do.

#!/usr/bin/env python3

import sys
import whois

def find_available_domains(min_chars, max_chars, charset, tlds):
    domains = ['']
    for character in range(max_chars):
        domains = build_domain_list(domains, charset)
    check_availability(clean_list(domains,min_chars),tlds)

def build_domain_list(domains, charset):
    result = domains[:]
    for domain in domains:
        for index in range(len(charset)):
            result.append(domain + charset[index])
    return list(set(result))

def clean_list(list_items, min_chars):
    del list_items[list_items.index('')]
    list_items.sort()
    for list_item in list_items:
        if len(list_item) < min_chars:
            del list_items[list_items.index(list_item)]
    return list_items

def check_availability(domains, tlds):
    for tld in tlds:
        for domain in domains:
            domain = domain + '.' + tld
            sys.stdout.write('checking: ' + domain + '          ')
            sys.stdout.flush()
            sys.stdout.write('\r')
            sys.stdout.flush()
            if (domain_available(domain)):
                print(domain + ' might be available.')

# Can be more reliable if checking through an API.
def domain_available(domain):
    try:
        w = whois.whois(domain)
        if w['status'] == None:
            return True
        return False
    except:
        return False

try:
    min_chars = int(input("Enter the Min number of characters (int): "))
    max_chars = int(input("Enter the Max number of characters (int): "))
except:
    print("Error: Must be a number, try again. Exiting script.")
    sys.exit()
charset = input("Enter the character sets (string or alphabets if left empty): ")
tlds = input("Enter the TLDs (strings separated with space - e.g:- io com co): ")
tlds = tlds.split()
find_available_domains(min_chars, max_chars, charset if charset != '' else 'abcdefghijklmopqrstuvwxyz', tlds)