Rails: Only using regex when data is present

Question

Right now, I've got a regular expression that validates a user's facebook link, as such:

facebook_regex = /(http:\/\/)?(https:\/\/)?(www.)?facebook.com\/[a-zA-Z0-9\.]*/i
validates :facebook, :format => { :with => facebook_regex }

The regex itself works just fine, but I'm trying to make the inclusion of a FB link optional, should the user not want theirs posted. However, my validation is kicking up an error if the Facebook field is left blank.

What's the best way to handle this?

You didn't ask, but this might be a slightly [better pattern](http://refiddle.com/2nj) (doesn't allow two protocols but an empty path) or you can go [all the way](http://stackoverflow.com/a/190405/95033). :) — Wolfram, Jul 17 '12 at 21:41

score 4 · Accepted Answer · answered Jul 17 '12 at 21:01

4

Try adding allow_blank: true to the validation:

validates :facebook, :format => { :with => facebook_regex }, :allow_blank => true

You could also add in an unless:

validates :facebook, :format => { :with => facebook_regex }, :unless => :blank?

answered Jul 17 '12 at 21:01

Chris

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score 0 · Answer 2 · answered Jul 17 '12 at 21:02

0

allow_blank is the option you're looking for:

validates :facebook, format: { with: facebook_regex , allow_blank: true}

answered Jul 17 '12 at 21:02

stfcodes

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score 0 · Answer 3 · answered Jul 17 '12 at 21:02

0

Actually, I found the answer right here: http://guides.rubyonrails.org/active_record_validations_callbacks.html

Turns out you can pass an option called :allow_blank that does exactly what I was hoping for!

answered Jul 17 '12 at 21:02

Adam Templeton

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Rails: Only using regex when data is present

3 Answers3