Make Blank Params[] Nil

Make blank params[] nil

Consider what you're doing here by using filters in the controller to affect how a model behaves when saved or updated. I think a much cleaner method would be a before_save call back in the model or an observer. This way, you're getting the same behavior no matter where the change originates from, whether its via a controller, the console or even when running batch processes.

Example:

class Customer < ActiveRecord::Base
  NULL_ATTRS = %w( middle_name )
  before_save :nil_if_blank

  protected

  def nil_if_blank
    NULL_ATTRS.each { |attr| self[attr] = nil if self[attr].blank? }
  end
end

This yields the expected behavior:

>> c = Customer.new
=> #<Customer id: nil, first_name: nil, middle_name: nil, last_name: nil>
>> c.first_name = "Matt"
=> "Matt"
>> c.middle_name = "" # blank string here
=> ""
>> c.last_name = "Haley"
=> "Haley"
>> c.save
=> true
>> c.middle_name.nil?
=> true
>>

How to remove empty parameters from params hash?

Put this after the hash:

.reject{|_, v| v.blank?}

Passing params without nil

You can get category parameters by defining a method like,

def category_params
  params.fetch(:category, {})
end

And, then look up for Products by,

@search_name = params[:search]
@category = category_params[:name]
@products = Product.search(@search_name, @category)

In my opinion, if you are making a direct query on Product, then you should do like,

def product_params
  params.fetch(:product, {})
end

@category = product_params[:category_id]
@title = product_params[:title]
@products = Product.search(@category, @title)

And in product model,

def self.search(category, title)
  where("category_id = ? AND title LIKE ?", category, "%#{title}%")
end

If params[:object].nil? :object = value

I my opinion it is the models responsiblity to keep itself in a valid state. Furthermore it is the best solution according to DRY principles if multiple controllers change of update the same model. Therefore I would do something like this in the Post model:

before_validation :set_default_title

private
def set_default_title
  self.title = title.presence || 'Unnamed'
end

Rails converts empty arrays into nils in params of the request

After much searching, I discovered that you starting in Rails 4.1 you can skip the deep_munge "feature" completely using

config.action_dispatch.perform_deep_munge = false

I could not find any documentation, but you can view the introduction of this option here:
https://github.com/rails/rails/commit/e8572cf2f94872d81e7145da31d55c6e1b074247

There is a possible security risk in doing so, documented here: https://groups.google.com/forum/#!topic/rubyonrails-security/t1WFuuQyavI

Rails - Strong parameters with empty arrays

The temporary solution I've come down to is:

params[:foo_ids] ||= [] if params.has_key?(:foo_ids)
params.permit(foo_ids: [])

Here, foo_ids is set to an empty array only if is passed. If it is not passed in the request, it is ignored.

I'm still hoping to find a better solution to this, as this sort of thing will be quite common in the project I'm working on - please do suggest better ideas if you have any.

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