Programmatically apply an ActiveRecord scope that accepts arguments

Question

I'm building a system where it is necessary to programmatically apply one or more where clauses to an ActiveRecord Relation object. This works great in the following situation:

Assume the Employee model has scope called "male"

then:

filter_name = "male"
Employee.send(filter_name)  # works

However with scopes that take arguments ,

"NoMethodError (undefined method `age_range(45, 55)'

eg with this scope:

scope :age_range, ->(low, high) {where("age >= #{low} AND age <= #{high}")}

The scope works fine in the console eg

Employee.age_range(45,55)

Thanks for any advice.

Answer 1

Object# send accepts the name of the method and its arguments:

name = :age_range
low  = 45
high = 55
Employee.send(name, low, high)

I would recommend to use Object# public_send , to make sure you only use publicly accessible API:

Employee.public_send(name, low, high)