Question

I am using Ruby on Rails 3 and I am trying to get a regex string from an SQL database for a later in a validation method.

In a database migration I have:

create_table :profile_authorizations do |t|
  t.string  :param
  t.string  :param_value
end

In a model I have:

class User < ActiveRecord::Base
  email_regex = Parameter.find_by_param('regex').param_value

  validates :email,
    :format => { :with => email_regex }
end

In the database I create the regex for email in this way:

Parameter.create(:param => 'regex', :param_value => '/\A[a-zA-Z0-9_\.]+@[a-zA-Z0-9-]+\.[a-zA-Z]{0,4}\z/i')

Using that code I get this error:

ArgumentError
A regular expression must be supplied as the :with option of the configuration hash

I tryed also to use these

Parameter.find_by_param('regex').param_value.to_s
Parameter.find_by_param('regex').param_value.to_i

but it doesn’t work.

What is it wrong?

---

This code

@email_regex = Parameter.find_by_param('regex').param_value
<%= debug @email_regex %>

will result in this output

--- /\A[a-zA-Z0-9_\.]+@[a-zA-Z0-9-]+\.[a-zA-Z]{0,4}\z/i

---

I tryed this:

Regexp.new(Parameter.find_by_param('regex').param_value)

It dosn’t seem to generate errors, but the validation “:with => email_regex” dosn’t recognize the regex.

In this case the debug results as

--- !ruby/regexp /\/\A[a-zA-Z0-9_\.]+@[a-zA-Z0-9-]+\.[a-zA-Z]{0,4}\z\/i/

Answer 1

Found the solution (reading the Regex.new guide):

In the database you must put the regex without ‘/’ or ‘\A’ (at the begin) and ‘\z’ (at the end):

[a-zA-Z0-9_\.]+@[a-zA-Z0-9-]+\.[a-zA-Z]{0,4}

For use it you can do just this:

Regexp.new(Parameter.find_by_param('regex').param_value)