Rack-Attack: Array of IP addresses

Question

I'm trying to create an array of IP addresses so that when the application is ran Rack-Attack can identify from the set of IP addresses that are allowed to access the application. So what I have done is as followed:

  a = "127.0.0.1"
  Rack::Attack.blacklist('allow from localhost') do |req|
    p "#{'127.0.0.1' == req.ip} "
   a != req.ip 
  end

The above works, so localhost can access the application but I have tried the following below which seems to not work what so ever:

a = "127.0.0.1", "1.2.3.4"
  Rack::Attack.blacklist('allow from localhost') do |req|
    a.select{|x| x != req.ip}.join("")
  end

Can someone explain what the correct way would be to do this. You can see that I create an array. I want Rack::Attack to detect whether the IP address in the array has access or not.

Answer 1

An efficient way to do this would be to use a Set, a container that's like an array but provides fast lookup on individual, unique elements.

So, rewritten with that in mind:

allowed = %w[ 127.0.0.1 1.2.3.4 ].to_set

Rack::Attack.blacklist('allow from localhost') do |req|
  !allowed.include?(req.ip)
end

In your original declaration:

a = "x", "y"

In this case a is assigned to the first thing in that list, "x", and the rest is ignored.