Easy API Cache

cache.rb

@api_cache = {}
def api_cache id:, threshold:, due:, &blk
  @api_cache[id] ||= { cache: {} }
  due_time = case due
             when Numeric  then Time.now + due
             when Time     then due
             end
  proc do |*args| # args is the key
    @api_cache[id][:cache].delete_if { |_key, item| item[:due] < Time.now }
    unless @api_cache[id][:cache][args]
      if threshold > @api_cache[id][:cache].size
        @api_cache[id][:cache][args] = { due: due_time, data: blk[*args] }
      else
        next 'Sorry but we\'ve touched the limit.'
      end
    end
    @api_cache[id][:cache][args][:data]
  end
end
=begin
# 汇率转换
require 'json'
require 'net/http'
@exchache =
  api_cache id: 'exchange', threshold: 42, due: 86400 do |from|
    Net::HTTP.get(URI "http://api.fixer.io/latest?base=#{from}")
  end
=end