Key Server 🔑

key_server.rb

require 'sinatra'
require 'json'

BLOCKING_TIME = 60
EXPIRY_TIME = 300

all_keys = {}
blocked_keys = []
available_keys = []

# Generate a key
post '/keys' do
  headers 'Content-Type' => 'application/json'

  now = Time.now
  key = now.to_f.to_s.split(".").join

  all_keys[key] = now.to_i
  available_keys << key
  status 200
end

# Serve an existing available key
get '/key' do
  headers 'Content-Type' => 'application/json'

  data = {}
  if available_keys.count == 0
    status 404
  else
    now = Time.now
    key = available_keys.sample
    blocked_keys << key
    available_keys.delete(key)
    all_keys[key] = now.to_i

    status 200
    data = {key: key, expires_at: (now.to_i + BLOCKING_TIME)}
  end
  body data.to_json
end

# Delete a key
delete '/keys/:id' do
  headers 'Content-Type' => 'application/json'

  status(404) and return unless all_keys[params[:id]]

  all_keys.delete(params[:id])
  available_keys.delete(params[:id])
  blocked_keys.delete(params[:id])
  status 200
end



# Unblock a key
get '/keys/:id/unblock' do
  headers 'Content-Type' => 'application/json'

  status(404) and return unless all_keys[params[:id]]

  blocked_keys.delete(params[:id])
  available_keys << params[:id]
  status 200
end

# Status
get '/' do
  headers 'Content-Type' => 'application/json'

  status 200
  data = {all: all_keys, available: available_keys, blocked: blocked_keys}
  body data.to_json
end

# Refresh a key
get '/keys/:id/refresh' do
  headers 'Content-Type' => 'application/json'

  now = Time.now
  data = {}
  if all_keys[params[:id]]
    all_keys[params[:id]] = now.to_i

    status 200
    data = {key: params[:id], expires_at: (now.to_i + BLOCKING_TIME)}
  else
    status 404
  end
  body data.to_json
end

Thread.new do
  while true
    for key, assignment_time in all_keys do
      now = Time.now
      # unblock after 60 seconds
      if (now.to_i - assignment_time) >= BLOCKING_TIME && blocked_keys.include?(key)
        blocked_keys.delete(key)
        available_keys << key
      end

      # delete after 300 seconds
      if (now.to_i - assignment_time) >= EXPIRY_TIME
        blocked_keys.delete(key)
        available_keys.delete(key)
        all_keys.delete(key)
      end
    end
    sleep(1)
  end
end