Ruby 2 Keyword Arguments and ActionController::Parameters

Question

I have a rails 4 application that is running on ruby 2.1. I have a User model that looks something like

class User < ActiveModel::Base
  def self.search(query: false, active: true, **extra)
    # ...
  end
end

As you can see in the search method I am attempting to use the new keyword arguments feature of ruby 2.

The problem is that when I call this code from in my controller all values get dumped into query.

params

{"action"=>"search", "controller"=>"users", query: "foobar" }

Please note that this is a ActionController::Parameters object and not a hash as it looks

UsersController

def search
  @users = User.search(params)
end

I feel that this is because params is a ActionController::Parameters object and not a hash. However even calling to_h on params when passing it in dumps everything into query instead of the expected behavior. I think this is because the keys are now strings instead of symbols.

I know that I could build a new hash w/ symbols as the keys but this seems to be more trouble than it's worth. Ideas? Suggestions?

Answer 1

Keywords arguments must be passed as hash with symbols, not strings:

class Something
  def initialize(one: nil)
  end
end

irb(main):019:0> Something.new("one" => 1)
ArgumentError: wrong number of arguments (1 for 0)

ActionController::Parameters inherits from ActiveSupport::HashWithIndifferentAccess which defaults to string keys:

a = HashWithIndifferentAccess.new(one: 1)
=> {"one"=>1}

To make it symbols you can call symbolize_keys method. In your case: User.search(params.symbolize_keys)

Answer 2

I agree with Morgoth, however, with rails ~5 you will get a Deprecation Warning because ActionController::Parameters no longer inherits from hash. So instead you can do:

params.to_unsafe_hash.symbolize_keys

or if you have nested params as is often the case when building api endpoints:

params.to_unsafe_hash.deep_symbolize_keys

You might add a method to ApplicationController that looks something like this:

def unsafe_keyworded_params
  @_unsafe_keyworded_params ||= params.to_unsafe_hash.deep_symbolized_keys
end