Rails check if params exist in the controller

Question

I have a factor controller which takes factor values for two different types of factors

1. Primary Factor
2. Secondary Factor

And I pass them as params as follows:

class FactorController < AdminController

  def create
    if primary_factor_params                              ## LINE 5
      do something
    elsif secondary_factor_params
      do something else
    end
  end

  def primary_factor_params
    params.require(:primary).permit(:user_id,            ## LINE 70
                                           :primary_factors)
  end

  def secondary_factor_params
    params.require(:secondary).permit(:user_id,
                                        :secondary_factors)
  end
end

But in the above whenever I try to pass a secondary_factor I get the following error:

ActionController::ParameterMissing (param is missing or the value is empty: primary):
  app/controllers/factors_controller.rb:70:in `primary_factor_params'  app/controllers/api/v1/admin/factors_controller.rb:5:in `create'

So to me it seems that this error is coming up because I didn't have any values for primary_factor_params in this condition and that's way it throws the error because of the first if condition.

I've tried:

primary_factor_params.exists?
primary_factor_params.has_key?(:primary_factors)
....

But all of them throw the same error since primary_factor_params doesn't exist. Is there a way to test this without throwing an error for missing params?

Solution 1

The problem is this line params.require(:primary) saying that the parameter is required, so attempting to do like params.require(:primary).exists? wont help you if you do not have a :primary param at all because the require already failed.

You need to check its existance on params itself. For example params.has_key?(:primary).

Dependening on your use case, you might also use params.permit(:primary) directly on params as well. See the API docs for detailed information on how ActionController::Parameters (the class for params) can be used.

http://api.rubyonrails.org/classes/ActionController/Parameters.html#method-i-permit

Solution 2

you can check your params existence in your case by params[:primary].present? I think this is the easiest way

Comments

[anonn023432]

Yes, this makes perfect sense, I blanked out on the fact that I need to test on params because primary_factor_params wouldn't exist in this case at all

[Kyle K]

@Fire Lancer thank you! I just ran into a situation where I had to conditionally set a base variable to look up associated records using different relationships depending on the model requesting the associated records and this worked perfectly!