Rails keeping params DRY

Question

I have a model named "seo"

class Seo < ApplicationRecord
    belongs_to :seoable, polymorphic: true
    # more code
  end

Many models in my application has_one seo. For example

 class Post < ApplicationRecord
    has_one :seo, as: :seoable
    accepts_nested_attributes_for :seo, dependent: :destroy
    # more code
  end

My question is, what is the best way to keep params in my controllers dry. For example I have the following code in my posts_controller

def post_params
  params.require(:post).permit(seo_attributes: [:id, :title, :meta_description, :etc])
end

Every model will repeat the above. How do I keep this DRY?

score 2 · Accepted Answer · answered Sep 20 '19 at 06:46

I think this is an example where you could use a concern:

# in app/models/concern/seoable.rb
require 'active_support/concern'

module Seoable
  extend ActiveSupport::Concern
  included do
    has_one :seo, as: :seoable
    accepts_nested_attributes_for :seo, dependent: :destroy
  end
end

# in your models
class Post < ApplicationRecord
  include Seoable
end

And for the controllers, you could add a method into AplicationController that allows simplified the call:

# in the application_controller
def params_with_seo_attributes(namespace)
  params.require(namespace).permit(seo_attributes: [:id, :title, :meta_description, :etc])
end

# and use it in your controllers like this
def post_params
  params_with_seo_attributes(:post)
end

Apparently permit can be used once. I modified your code a bit. def params_with_seo_attributes [seo_attributes: [:id, :title, :meta_description, :etc]] end in my post controller def post_params permitted_params = [:foo, :bar] + params_with_seo_attributes params.require(:post).permit(permitted_params) end — Vikram Sharma, Sep 21 '19 at 05:27

score 0 · Answer 2 · answered Sep 20 '19 at 06:42

0

You could make one controller that has that post_params method, and then the rest of the controllers that need to use it, can inherit from that controller

answered Sep 20 '19 at 06:42

Jason Carty

1,217
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Vishal · Answer 3 · 2019-09-20T06:48:24.767

0

So if the has_one :seo, as: :seoable and accepts_nested_attributes_for :seo, dependent: :destroy are repeated in multiple models then you can use Rails Concerns for it.

If you want to learn how to make concerns see this question

edited Sep 20 '19 at 06:48

answered Sep 20 '19 at 06:43

Vishal

751
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score 0 · Answer 4 · answered Sep 20 '19 at 06:44

You can have a base controller like the follows

class ResourceController < ApplicationController
        private
        def resource_params
            params.require(resource_name).permit(seo_attributes: [:id, :title, :meta_description, :etc])
        end
end

And in post controller you can use them as dry like this

class PostController < ResourceController    
            def resource_name
                :post
            end
end

And again use in any other controller like Blog as follows

class BlogController < ResourceController    
                def resource_name
                    :blog
                end
    end

Rails keeping params DRY

4 Answers4