Rails 4 Postgres Array attribute: how can I ensure that the attribute is an array during validation?

Hi,

I just started experimenting with the native Postgress array type in
Rails
4, and I’m running into an issue I can’t figure out. I want the app to
raise an error if the value for an array attribute is not an array.

Before, when I was using a regular text type for the field, and
serializing
it with Rails, I was able to make sure the attribute was an array with a
custom validation like this:

def format_of_admin_email regexp = /.+@.+…+/i if admin_emails.present?
&&
(!admin_emails.is_a?(Array) || admin_emails.detect { |a|
a.match(regexp).nil? }) errors[:base] << “admin_emails must be an array
of
valid email addresses” end end

But now that the field is a Postgres array, it seems like Rails
automatically converts the string input into an empty array, so the
validation never fails. Here’s my migration:

class AddAdminEmailsToLocations < ActiveRecord::Migration def change
add_column :locations, :admin_emails, :text, array: true end end

If I create a Location where admin_emails is a string:

Location.create!(admin_emails: “this should fail”)

it doesn’t raise a validation error, and it sets admin_emails to an
empty
array.

Am I doing something wrong or is this a bug in Rails?

I also tried checking if the input is an array in a before_validation
callback, and added a puts admin_emails.present?, but it returned false,
as
if it never saw the String input.

Try adding return false

Thanks,

Jordon B.

On 4/11/2014 10:18:09 AM, Moncef Belyamani
[email protected]wrote:
Hi,
I just started experimenting with the native Postgress array type in
Rails 4, and I’m running into an issue I can’t figure out. I want the
app to raise an error if the value for an array attribute is not an
array.

Before, when I was using a regular text type for the field, and
serializing it with Rails, I was able to make sure the attribute was an
array with a custom validation like this:
def format_of_admin_email regexp = /.+@.+..+/i if admin_emails.present?
&& (!admin_emails.is_a?(Array) || admin_emails.detect { |a|
a.match(regexp).nil? }) errors[:base] << “admin_emails must be an array
of valid email addresses” end end
But now that the field is a Postgres array, it seems like Rails
automatically converts the string input into an empty array, so the
validation never fails. Here’s my migration:
class AddAdminEmailsToLocations < ActiveRecord::Migration def change
add_column :locations, :admin_emails, :text, array: true end end
If I create a Location where admin_emails is a string:
Location.create!(admin_emails: “this should fail”)
it doesn’t raise a validation error, and it sets admin_emails to an
empty array.
Am I doing something wrong or is this a bug in Rails?
I also tried checking if the input is an array in a before_validation
callback, and added a puts admin_emails.present?, but it returned false,
as if it never saw the String input.

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