Check for valid domain name in a string?

Question

I am using python and would like a simple regex to check for a domain name's validity. I check at least write domain name.

url = 'https://stackoverflow'
        keyword = 'foo'
        with self.assertRaises(ValueError):
            check_keyword(url, keyword)

I try unit testing on url textfield and there is main.py page where I done the validation main.py-

def check_keyword(url, keyword):

if re.match("^(((([A-Za-z0-9]+){1,63}\.)|(([A-Za-z0-9]+(\-)+[A-Za-z0-9]+){1,63}\.))+){1,255}$" ,url):
   return ValueError("Invalid")

Example

• www.google (Invalid)

• https://stackoverflow (Invalid)

Answer 1

The source of the validators module shows, that this is maybe a little more complex task.

You could use that module:

>>> import validators
>>> validators.domain('example.com')
True

>>> validators.domain('example.com/')
ValidationFailure(func=domain, ...)

Or you can use the RFCs for Domain names to construct your own checker.