# Validating and saving a MAC address using only one format

**URL:** <https://www.ruby-forum.com/t/validating-and-saving-a-mac-address-using-only-one-format/74750>\
**Category:** Rails\
**Created:** [November 7, 2006, 10:55am UTC](https://www.ruby-forum.com/t/validating-and-saving-a-mac-address-using-only-one-format/74750 "2006-11-07T10:55:10Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![brainstorm](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/919ad9/32.png) [@brainstorm](https://www.ruby-forum.com/u/brainstorm)\
**Post date:** [November 7, 2006, 10:55am UTC](https://www.ruby-forum.com/t/validating-and-saving-a-mac-address-using-only-one-format/74750/1 "2006-11-07T10:55:10Z")

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Hi people,

I’m developing my first rails app, and I’m having a little issue with  
model validations:

==  
require\_gem ‘netaddr’

(…) (AR model definition)

# protected def validate @eui = NetAddr::EUI.create(mac).address(:Delimiter=\>’:’) #@eui.address(:Delimiter=\> ‘.’) rescue NetAddr::ValidationError errors.add(mac, “Incorrect MAC address format”) end

My idea is to ensure at the model level, that a MAC address is  
properly filtered and saved using the following format:

0000.1111.2222

… and automatically convert the following netaddr-supported formats  
to the above one:

00:00:11:11:22:22  
00-00-11-11-22-22  
(…)

Now when I try to add a MAC using any format, it saves ‘000011112222’  
on the DB and I cannot figure why it’s happening by looking at netaddr  
code.

NetAddr uses gsub!(/[.:-]/, ‘’) all around to remove formating  
chars, but ".address(:Delimiter =\>’.’) " should put ‘.’-format back to  
the MAC string, shouldn’t it ?

Thanks in advance.

---

<div class="post-metadata">

**Author:** ![brainstorm](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/919ad9/32.png) [@brainstorm](https://www.ruby-forum.com/u/brainstorm)\
**Post date:** [November 7, 2006, 5:38pm UTC](https://www.ruby-forum.com/t/validating-and-saving-a-mac-address-using-only-one-format/74750/2 "2006-11-07T17:38:33Z")

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When tried standalone (outside rails), it works like a charm :\_/ What  
i’m doing wrong with exception management ?

irb(main):001:0\> require\_gem ‘netaddr’  
=\> true  
irb(main):002:0\>  
NetAddr::EUI.create(‘00:00:11:11:22:22’).address(:Delimiter=\>’.’)  
=\> “0000.1111.2222”  
irb(main):003:0\>  
NetAddr::EUI.create(‘00:00:11:11:22:22’).address(:Delimiter=\>’-’)  
=\> “00-00-11-11-22-22”  
irb(main):004:0\>  
NetAddr::EUI.create(‘00:00:11:11:22:22’).address(:Delimiter=\>’:’)  
=\> “00:00:11:11:22:22”  
irb(main):005:0\>

---

<div class="post-metadata">

**Author:** ![brainstorm](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/919ad9/32.png) [@brainstorm](https://www.ruby-forum.com/u/brainstorm)\
**Post date:** [December 5, 2006, 6:28pm UTC](https://www.ruby-forum.com/t/validating-and-saving-a-mac-address-using-only-one-format/74750/3 "2006-12-05T18:28:09Z")

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Also tried with ActiveRecord callbacks used in the model:

def after\_validation  
self.mac = NetAddr::EUI.create(mac).address(:Delimiter=\>’.’)  
rescue NetAddr::ValidationError  
errors.add(mac,“Incorrect MAC address format”)  
end

But the ValidationError never raises :-/ Any bet ?

Thanks