Rails validating with condition block

Question

Rails AR. validate one field, with 4 validators & 2 condition block

validates :inn,
 presence: { if: -> { user.is_a?(Client) } },
 inn: { if: -> { user.is_a?(Client) } },
 uniqueness: { if: -> { user.is_a?(Client) } },
 absence: { if: -> { user.is_a?(Department) } }

Could I have some tips on refactoring this?

• tokland: inn as an option of validates?

Answer 1

You can try something like this (obviously names can be shorter):

if_user_is_a = ->(klass) { { if: -> { user.is_a?(klass) } } }
validates :inn, presence: if_user_is_a[Client], ..., absence: if_user_is_a[Department]

or

if_user_is_a = ->(klass) { { if: -> { user.is_a?(klass) } } }
if_user_is_a_client = if_user_is_a[Client]
...
validates :inn, presence: if_user_is_a_client, ...

• Alex Antonov: It seems better, but maybe is it something better than that?
• Alex Antonov: It seems there isn't any better than that. Regards!

Answer 2

Why don't you split both conditions into 2 diffrent validations? I think it's cleaner and easier to read (ie more maintenable).

validates :inn, presence: true, uniqueness: true, if: :user_is_client #no idea about that `inn` option on your example
validates :inn, absence: true, if: :user_is_department
def user_is_client
 user.is_a?(Client)
end
def user_is_department
 user-is_a?(Department)
end

Personally, I prefer to be more verbose some times. Also, I think this way conditions are checked only once each, the other way each condition is checked for each validation since rails has to evaluate all blocks.

Answer 3

You can try to use a method instead of repeat yourself 4 times

Something like:

validates :inn,
 presence: { inn_meth { Client } },
 inn: { inn_meth { Client } },
 uniqueness: { inn_meth { Client} },
 absence: { inn_meth{ Department } }
def inn_meth
 if: -> { user.is_a?(yield) }
end