强参数：如何使用条件允许参数

Question

I wan't to permit certain parameters depending on the current user's role.

Eg: only permit the role attribute if the user is an administrator.

Is this possible?

Answer 1

Yes, it's possible.

You can do something like this :

def user_params
  # List of common params
  list_params_allowed = [:email, :title, :last_name, :first_name, :phone]
  # Add the params only for admin
  list_params_allowed << :role if current_user.admin?
  params.require(:user).permit(list_params_allowed)
end

This way, if later you have new params, you only have to add in one list (avoids error).

If you have more than one param to add for the admin, you can do this like this :

list_params_allowed << :role << other_param << another_param if current_user.admin?

Hope this help.

Answer 2

You can simply do the following:

def post_params
  allowed     = [:name, :age]
  conditional = Some_Condition_Applies ? [:title, :description] : []
  params_list = allowed + conditional
  params.require(:post).permit(params_list)
end