content: on init()
    script Cache
      property class : "Cache"
  
      on download(link)
        set link to quoted form of link
        set filename to POSIX path of (path to temporary items) & (do shell script "md5 <<< " & link)
        if not file_exists(filename) then try
          do shell script "curl -o " & quoted form of filename & " " & link
        end try
        return filename
      end download
    end script
  
    return Cache
  end init
  
  on file_exists(p)
    try
      get POSIX file p as alias
      return true
    on error
      return false
    end try
  end file_exists
  