problems with regex url validator - regex

Question

I'm trying to create a regex to test if a url is valid or not. I had a good example to work off of, but I had to tweak it a bit to make it fit my purpose:
^(https?:\/\/)(www\.)?(\w*\.)+([\w\-_~:/?#[\]#!$&'()*+,;=.])*$
It works fine for the most part, but it matches the following, which drives me nuts:
http://www..example..com
I tried forever and I just can't get the magical combination of characters to get it to ignore the above use case. What am I doing wrong?
Here's a list of things I want the regex to match (all of them are matched):
http://www.example.com
https://www.example.com
https://www.example.com/
https://example.com/
https://blog.example.com/
https://my.blog.example.com/
https://my.blog.example.co.uk/
https://www.example.com/#test
https://www.example.com#test
https://www.example.com/test.php
https://www.example.com/test.php?test=yes&testmore=yesevenmore
https://www.example.com/test.php#test
https://www.example.com/test.php?test=yes&testmore2=yesevenmore&whatnumber=42#test
https://www.example.com/test
https://www.example.com/test/
https://www.example.com/test/?test=yes&testmore2=yesevenmore&whatnumber=42
https://www.example.com/test/#test
https://www.example.com/test/?test=yes&testmore=yesevenmore&whatnumber=42#test
https://www.example.com/test/?test=yes&testmore=yesevenmore&whatnumber=42#test
https://www.blog.example.com/test/?test=yes&testmore=yesevenmore&whatnumber=42#test
https://www.my.blog.example.com/test/?test=yes&testmore=yesevenmore&whatnumber=42#test
https://my.blog.example.co.uk/?test=yes&testmore=yesevenmore&whatnumber=42#test
http://255.255.255.255
http://www.example.com:8008
http://www.example.com:8008/test/?test=yes&testmore=yesevenmore&whatnumber=42#test
Here's a list of things I DON'T want it to match:
www.example.com
example.com
*http://www.blog..example..com
*http://www..example.com
*http://www...example.com
*http://www..example..com
http://www.example.com | not valid
http://www.example.com|
255.255.255.255
* still matched
How can I prevent regex from matching the multidots?

Answer 1

Your pattern matches the dot literally \. as well as in the character class which is repeated 1+ times as a group and (\w*\.)+ also matches consecutive dots.
You could shorten the character class as some parts do not have to be escaped and \w also matches _
Using the characters from your character class that you accept to be valid you could repeat in a group matching what you want to allow excluding the dot and match a single dot at the end:
^https?:\/\/(?:[-\w~:/?#[\]#!$&'()*+,;=]+\.)*[-\w~:/?#[\]#!$&'()*+,;=]+$
That will match
^ Start of string
https?:\/\/ Match http:// or https://
(?: Non capturing group
[-\w~:/?#[\]#!$&'()*+,;=]+\. Match 1+ times any of listed, then match a .
)* Close group and repeat 0+ times
[-\w~:/?#[\]#!$&'()*+,;=]+ Match any of the listed 1+ times (note that there is no .)
$ End of string
Regex demo
A more specific variant:
^https?:\/\/\w+(?:\.\w+)*(?:[/#:][-\w~:/?#[\]#!$&'()*+,;=.]*)?$
Regex demo