Strong parameters for model with has_many nested attributes

Question

How can I use strong parameters for params like this:

{ 
  ... attributes of a model,
  related_model_attributes => [ 
       RANDOM_HASH_KEY => { attr_1 => value_1, ... other attributes },
       ANOTHER_RANDOM_KEY => { attr_1 => value_1, ... other attributes}
       ...
  ]
}

If I use the normal permit style like the ff snippet:

permit!(... model attributes, related_model_attributes: [{:attr_1, ..other attributes]])

it would throw and non-permitted error on the random hash key.

How do i use strong parameters together with has_many?

Answer 1

There is no officially sanctioned method for doing this other than the obvious, kind of ugly one.

Given a hash like this:

{ thing: {
    thangs_attributes: {
       'some_synethic_index' => { 
           attribute: value
        },
        'some_other_index'   => {
           attribute: value
        }
     }
 }

The idea is basically to allow the keys in the thang_attributes hash based on their appearance.

Something like this.

def thing_params
   thangs_attributes = params[:thing][:thangs_attributes].keys.each_with_object([]) do |k, memo|
      memo << { k => [:id, '_destroy', :attribute] }
   end

   params.require(:thing).permit(thangs_attributes: thangs_attributes)
end

Which should set up a nested hash for each random index key in thangs_attributes. Alternatively, and unsafely, you could call params.require(:thing).permit! which will permit any and all parameters.