rails validates_format_of with IP addresses - ruby-on-rails

Question

I'm allowing a user to enter IP addresses in an input field which may be of different types delimited by a comma, such as (in no particular order):
192.168.1.1,192.168.2.1-25,10.10.10.0/24,192.168.1.2
This 'string' would get saved in my DB under device.ips_to_scan.
I want to validates_format_of on these, but am finding it a little difficult to write a regex that seems to work in rails, while it does work on regex101 (https://regex101.com/r/nf2bnM/1):
validates_format_of :ips_scan, with: /\A([0-9]{1,3}\.){3}[0-9]{1,3}(\/([1-2][0-9]|[0-9]|3[0-2]))?(-([0-9]{1,3}))?,?\Z/i, on: :update
This one is expected to fail:
Started PUT "/devices/2" for 127.0.0.1 at 2018-02-19 22:03:15 -0500
Processing by DevicesController#update as HTML
Parameters: {"utf8"=>"✓", "authenticity_token"=>"EQCFG6/xoJHtP6Nd3oqaYRW6mypfEoCMrnio1yj6loP+KtvjgLZ9Gmhb0oTwCjD0RGH+qQuctZFVIvF5HBJcGw==", "device"=>{"ips_scan"=>"192.168.1.1,192.168.2.1-25,a.b.c.d", "ips_exclude"=>"10.10.10.1"}, "commit"=>"Save", "id"=>"2"}
User Load (0.8ms) SELECT "users".* FROM "users" WHERE "users"."id" = $1 ORDER BY "users"."id" ASC LIMIT $2 [["id", 2], ["LIMIT", 1]]
Device Load (1.6ms) SELECT "devices".* FROM "devices" WHERE "devices"."id" = $1 LIMIT $2 [["id", 2], ["LIMIT", 1]]
(0.5ms) BEGIN
User Load (0.7ms) SELECT "users".* FROM "users" WHERE "users"."id" = $1 LIMIT $2 [["id", 2], ["LIMIT", 1]]
(0.5ms) ROLLBACK
Redirected to http://localhost:3000/devices/2/edit
Completed 302 Found in 47ms (ActiveRecord: 12.1ms)
...But this one should have worked:
Processing by DevicesController#update as HTML
Parameters: {"utf8"=>"✓", "authenticity_token"=>"JJfmT/0l5MEDc+gUH/WHHp3bbgyzjGa0xTzaXM3E/WHLvbi30mI5SoYXmc0xdS2LzAALj+cCU6k+ZoPy+Sw3+Q==", "device"=>{"ips_scan"=>"192.168.1.1,192.168.2.1-25,192.168.1.2", "ips_exclude"=>"10.10.10.1"}, "commit"=>"Save", "id"=>"2"}
User Load (0.9ms) SELECT "users".* FROM "users" WHERE "users"."id" = $1 ORDER BY "users"."id" ASC LIMIT $2 [["id", 2], ["LIMIT", 1]]
Device Load (0.7ms) SELECT "devices".* FROM "devices" WHERE "devices"."id" = $1 LIMIT $2 [["id", 2], ["LIMIT", 1]]
(0.6ms) BEGIN
User Load (0.7ms) SELECT "users".* FROM "users" WHERE "users"."id" = $1 LIMIT $2 [["id", 2], ["LIMIT", 1]]
(0.6ms) ROLLBACK
Redirected to http://localhost:3000/devices/2/edit
Completed 302 Found in 17ms (ActiveRecord: 3.5ms)
Last thing I can think of, is that I do have strong parameters, but I'm permitting ips_scan, so that this shouldn't be an issue:
def update
if #device.update(device_params)
flash[:notice] = 'Successful update'
respond_with :edit, :device
else
flash[:warning] = 'Unable to update'
respond_with :edit, :device
end
end
private def device_params
params.require(:device).permit(:token, :ips_scan, :ips_exclude)
end
I'm hoping you rubyist's out there have a eloquent solution. The first thought that comes to mind is that I have to split the string, and check each element sequentially to ensure it matches instead.

Answer 1

While I'm still open to a nice eloquent one-liner within the Model itself, I was able to get this working through creating a concern:
models/concerns/ip_validator.rb
class IpValidator < ActiveModel::Validator
def validate(record)
ips = record.ips_scan.split(',')
ips.each do |ip|
/([0-9]{1,3}\.){3}[0-9]{1,3}(\/([1-2][0-9]|[0-9]|3[0-2]))?(-([0-9]{1,3}))?/ =~ ip
record.errors.add(:ips_scan, ' is not valid') unless $LAST_MATCH_INFO
end
end
end
The call in my model now looks like:
validates :ips_scan, :ips_exclude, ip: true, on: :update

Answer 2

You can use this method in your custom validator to check an IP address
require 'ipaddr'
def valid_ip_addr?(ip_addr)
IPAddr.new(ip_addr)
true
rescue IPAddr::InvalidAddressError => _error
false
end