Rails - how to check if key and value in a hash match given parameters?

Question

I am working on a simple authorization in a Rails 4 app. Each user has a role; then I set up pages they can access, for example:

AUTH_MODERATOR_DEFINITIONS = {"articles"     => "index",
                              "readers"  => "index"}

Then, in a controller action, I will call:

def index
  check_permissions(current_admin)
  ...
end

And in the ApplicationController:

  def check_permissions(current_admin)
    if current_admin.role == 1 # for moderators
      # find a pair key-vale AUTH_DISPATCHER_DEFINITIONS that matches `params[:controller]` and `params[:action]
    else
      redirect_to root_path, :alert => "No permission"
    end
  end

But how to search a hash according to key AND value?

Thank you in advance.

Wand Maker · Accepted Answer · 2015-09-02 20:01:02Z

1

You can do something like this:

key = params[:controller]
value= params[:action]
p is_permitted = (AUTH_MODERATOR_DEFINITIONS[key] == value)

However, I think you may revise values in your hash to be array at some point, as it is unlikely that a controller will have only one action, and hence, user can have access to multiple actions. For example:

AUTH_MODERATOR_DEFINITIONS = {
    "articles" => "index",
    "readers"  => "index",
    "commenters"  => ["index","new","update"] # Added by me to show possible use case
}

Considering the above scenario, I think you can do something like this. This will work in both scenarios (your example, and my extension to that example)

key = params[:controller]
value= params[:action]

p is_permitted = [AUTH_MODERATOR_DEFINITIONS[key]].flatten.include?(value)

edited Sep 2, 2015 at 20:01

answered Sep 2, 2015 at 19:44

Wand Maker

18.8k9 gold badges58 silver badges90 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Arup Rakshit Over a year ago

This is best, as it is o(1).

Arup Rakshit Over a year ago

Your first solution is what I liked most.

user984621 Over a year ago

Hi Wand, thank you for the answer. I am testing it, but the output is still false (p is_permitted), no matter if I am on an approved page or not. Do I overlook something or what I do wrong?

Collectives™ on Stack Overflow

Rails - how to check if key and value in a hash match given parameters?

1 Answer 1

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related