rails 4 URI domain bad argument

Question

I'm trying to write a simple validation to check if a user's domain name is valid. Here's the model:

class User < ActiveRecord::Base
  require 'net/http'
  validate :domain_check

  def domain_check
    uri = URI(domain)

    request  = Net::HTTP.new uri.host
    response = request.request_head uri.path

    if response.code.to_i > 400
        errors.add(:domain, "This doesn't appear to be an valid site.")
    end
  end
end

This is based off the example in the Rails how to here.

However this keeps throwing an error bad argument (expected URI object or URI string) about the line

uri = URI(domain)

I assume the domain variable is not getting to the function-- it seemed odd in the example in the Rails book that it didn't pass any variable, but the form vars are getting passed in correctly (I can see them in the debug info) and the form item domain is populated.

How do I pass in the domain var correctly so this custom validation method will work?

Answer 1

The problem was (predictably I guess) strong parameters. I had to write a custom parameter sanitizer routine for Devise, so the form's domain could be accepted by the model.

More info on this: https://github.com/plataformatec/devise#strong-parameters