Rlimiter

gem 'rlimiter'

CLIENT = 'redis' # Recommended and the only client for now
HOST = 'rds.host.foobaz' # Redis server hostname, enter 'localhost' if the redis server is on the same machine
PORT = 6379 # Default port, could be left empty

# Initializes the Rlimiter static class for usage  
Rlimiter.init(client: CLIENT, host: HOST, port: PORT)

  LIMIT_COUNT = 100 # Max number of hits allowed
  
  LIMIT_DURATION = 60 # Duration in which the max hits are applicable (in seconds)
  # After the aforementioned duration has elapsed, hit counter is reset to 0. 
  
  LIMIT_KEY = 'send_mobile_otp_limit' # Unique key for each operation that has to be rate limited
  
  
  # Implementation
  
  return send_mobile_otp if Rlimiter.limit(LIMIT_KEY, LIMIT_COUNT, LIMIT_DURATION)
  return limit_exceeded_message
  
  # :send_mobile_otp is the function that has to be rate limited, Rlimiter.limit call increments the hit count and 
  # returns true if the operation's limit has not been exceeded, otherwise returns false. 

    
    @phone_number = '2947126943'
    @limit_key = generate_limit_key
    @limit_count = fetch_limit_count
    limit_not_breached = Rlimiter.limit(@limit_key, @limit_count, DEFAULT_LIMIT_DURATION)
    if limit_not_breached
      {
        :status_code => 200,
        :otp_dispatch_status => send_mobile_otp,
        :requests_left => @limit_count - Rlimiter.current_count(@limit_key)
      }
    else
      {
        :status_code => 429,
        :otp_dispatch_status => nil,
        :requests_left => 0,
        :next_request_in => Rlimiter.next_in(@limit_key, DEFAULT_LIMIT_DURATION)
      }
    end
    
    # ..........
    
    def generate_limit_key
      "#{LIMIT_KEY_PREFIX}.#{@phone_number}"
    end
    
    def fetch_limit_count
      return USA_LIMIT_COUNT if number_from_usa?(@phone_number)
      return INDIA_LIMIT_COUNT if number_from_india?(@phone_number)
      DEFAULT_LIMIT_COUNT  
    end
    
    # ..........
    
end