Rails 3: Validate IP String

Question

In Rails 3, is there a built in method for seeing if a string is a valid IP address?

If not, what is the easiest way to validate?

Does this answer your question? [How do I check whether a value in a string is an IP address](https://stackoverflow.com/questions/3634998/how-do-i-check-whether-a-value-in-a-string-is-an-ip-address) — salty, Oct 31 '22 at 20:34

Jack · Answer 1 · 2012-09-27T06:55:15.260

71

Just wanted to add that instead of writing your own pattern you can use the build in one Resolv::IPv4::Regex

require 'resolv'

validates :gateway, :presence => true, :uniqueness => true,
  :format => { :with => Resolv::IPv4::Regex }

edited Sep 27 '12 at 06:55

answered Sep 26 '12 at 18:04

Jack

1,331
1
12
9

Not sure when they added this feature, but this is so much easier – Dex Sep 27 '12 at 01:08
1

Yes this is considerably easier. @Dex it's been around since at least ruby 1.9.2 – WarmWaffles Oct 05 '12 at 04:43
I can confirm [it's in Ruby 1.8.7](http://ruby-doc.org/stdlib-1.8.7/libdoc/resolv/rdoc/Resolv/IPv4.html) – davetapley Nov 14 '12 at 16:20
This is a very nice and clean solution. Works fine with Ruby 1.9.3 and Rails 3.2 – wingfire Mar 01 '13 at 12:13
9

Just want to note here that there's also the `Resolv::AddressRegex` expression, which permits both IPv4 & IPv6 addresses. – Matt Huggins Feb 24 '15 at 20:28

score 17 · Accepted Answer · edited Oct 08 '19 at 03:23

The Rails way to validate with ActiveRecord in Rails 3 is:

@ip_regex = /^([1-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])(\.([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])){3}$/

validates :gateway, 
          :presence => true, 
          :uniqueness => true,
          :format => { :with => @ip_regex }

Good resource here: Wayback Archive - Email validation in Ruby On Rails 3 or Active model without regexp

score 3 · Answer 3 · answered Feb 08 '17 at 16:52

3

You can also just call standard's library IPAddr.new that will parse subnets, IPV6 and other cool things: (IPAddr) and return nil if the format was wrong.

Just do:

valid = !(IPAddr.new('192.168.2.0/24') rescue nil).nil?  
#=> true

valid = !(IPAddr.new('192.168.2.256') rescue nil).nil?  
#=> false

answered Feb 08 '17 at 16:52

Francois

1,367
1
15
23

Way better solution than the accepted answer with the regex. – Lerk Mar 21 '22 at 14:58

yuku-t · Answer 4 · 2017-06-10T02:24:29.077

2

You can use Resolv::IPv4::Regex as Jack mentioned below if you don't need to accept subnets.

If you need to accept it, activemodel-ipaddr_validator gem may help you. (disclaimer: I'm the author of the gem)

validates :your_attr, ipaddr: true

edited Jun 10 '17 at 02:24

answered Feb 06 '15 at 02:01

yuku-t

29
4

Works well. Maybe worth adding the disclaimer that it is _your_ gem. – Shadwell Feb 17 '17 at 10:28

score 0 · Answer 5 · answered Mar 14 '15 at 06:15

0

You can also use Regexy::Web::IPv4 which can match ip addresses with port numbers too.

answered Mar 14 '15 at 06:15

pragma

1,290
14
16

score 0 · Answer 6 · answered Sep 20 '10 at 23:24

i dont know about RoR a lot, but if you dont find any built in method for validation of IP Address.

Try on this regular expression :

"^([1-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])(\.([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])){3}$"

to validate the IP Address.

I recently used it in one module so had it on desktop.

score 0 · Answer 7 · answered Sep 20 '10 at 23:25

0

You should use a Regular Expression

Here is one that does what you want:

/^([1-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])(\.
([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])){3}$/.match("#{@systemIP}")

answered Sep 20 '10 at 23:25

Pedro

11,514
5
27
40

Rails 3: Validate IP String

7 Answers7

Linked