Stuck in regex to detect URL for particular domain in c#

Question

I am trying to find out a URL which belongs to :

http://domain.blob.core.windows.net/ 
https://domain.blob.core.windows.net/

http://domain.blob.core.windows.net
https://domain.blob.core.windows.net

The regex which I wrote

Regex reg2= new Regex(@"^http(s?)://[0-9a-zA-Z](.blob.core.windows.net)(/?)$");
string url = "http://abc.blob.core.windows.net";
        if(reg2.IsMatch(url))
        {
            Console.WriteLine("Yes");
        }
        else
        {
            Console.WriteLine("no");
        }

I am not able to find the match. It's not working :( I am pretty weak in regex. So can anyone help me to find out my mistake? I am using c#. It always prints no.

UPDATE : FINAL Answer which worked for me:

Regex reg2 = new Regex(@"^http(s?)\:\/\/[0-9a-zA-Z]*(\.blob\.core\.windows\.net)
(/?)$");

Just in case anybody needs something like this :)

Try pasting your regex string into an expression analyser. Expresso is a decent one and was free last time I used it. — Phil Gan
– Phil Gan, Commented Dec 10, 2012 at 9:16

Chris Seymour · Accepted Answer · 2012-12-10 09:28:09Z

4

You were close with "^http(s?)://[0-9a-zA-Z](.blob.core.windows.net)(/?)$" however [0-9a-zA-Z] should be [0-9a-zA-Z]+ as you want to be multiple characters before .blob.core.windows.net not just a single character.

Note: you don't need brackets here if you not capturing parts of the match, the optional operator is applied to the previous character only so ^https?$ matches 'http' or 'https' and not '' as only the s is optional, Also escape all . characters as in regex the . characters matches any single character so to match a literal . you want \..

"^https?://[0-9a-zA-Z]+\.blob\.core\.windows\.net/?$"

edited Dec 10, 2012 at 9:28

answered Dec 10, 2012 at 9:15

Chris Seymour

86.4k32 gold badges166 silver badges209 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

Mandy Over a year ago

thanks a lot @sudo_O it helped me :) worked!! :) I can't accept answer for 5 mins.. i will asap :) Just one thing I want to mention Regex reg2 = new Regex(@"^http(s?)\:\/\/[0-9a-zA-Z]+(.blob.core.windows.net)(/?)$"); this is what I used. Thanks Phil and sudo_O both :)

Mandy Over a year ago

Hell yea @leppie what do I do then :(

Chris Seymour Over a year ago

@leppie I added info on escaping .

leppie Over a year ago

@Mandy: Escape the . with a \ EG blob\.core\.

Mandy Over a year ago

@leppie Regex reg2 = new Regex(@"^http(s?)\:\/\/[0-9a-zA-Z]*(\.blob\.core\.windows\.net)(/?)$"); Worked

Collectives™ on Stack Overflow

Stuck in regex to detect URL for particular domain in c#

1 Answer 1

5 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

5 Comments

Your Answer

Sign up or log in

Post as a guest

Related