Question

I’m trying to use a regular expression to validate the format of a URL in my Rails model. I’ve tested the regex in Rubular with the URL http://trentscott.com and it matched.

Any idea why it fails validation when I test it in my Rails app (it says “name is invalid”).

Code:

  url_regex = /^((http|https):\/\/)?[a-z0-9]+([-.]{1}[a-z0-9]+).[a-z]{2,5}(:[0-9]{1,5})?(\/.)?$/ix

  validates :serial, :presence => true
  validates :name, :presence => true,
                   :format    => {  :with => url_regex  }

Answer 1

Your input ( http://trentscott.com) does not have a subdomain but the regex is checking for one.

domain_regex = /^((http|https):\/\/)[a-z0-9]*(\.?[a-z0-9]+)\.[a-z]{2,5}(:[0-9]{1,5})?(\/.)?$/ix

Update

You also don’t need the ? after ((http|https):\/\/) unless the protocol is sometimes missing. I’ve also escaped . because that will match any character. I’m not sure what the grouping above is for, but here is a better version that supports dashes and groups by section

domain_regex = /^((http|https):\/\/) 
(([a-z0-9-\.]*)\.)?                  
([a-z0-9-]+)\.                        
([a-z]{2,5})
(:[0-9]{1,5})?
(\/)?$/ix