flooder middleware (simple one)

flooder.js

, function(req, res, next) {
    var ip = req.headers.ip

    if (typeof banned[ip] !== 'undefined') {
      if (Date.now() - banned[ip] > 3 * 60 * 60 * 1000) {
        try {
          delete banned[ip]
        } catch(e) {}
        log('UNBANNED:'.cyan, ip)
      } else {
        log('HAS BEEN BANNED:'.yellow, ip)
      }
    }
    
    if (typeof users[ip] === 'undefined' && typeof banned[ip] === 'undefined') {
      users[ip] = { visits: 0, timeout: null }
    }
    
    if (typeof banned[ip] === 'undefined') {
      users[ip].visits++
      clearTimeout(users[ip].timeout)
      users[ip].timeout = setTimeout(function() {
        try {
          delete users[ip]
        } catch(e) {}
      }, 5 * 1000)
    }
    
    if (typeof banned[ip] !== 'undefined' || users[ip].visits > 30) {
      if (typeof banned[ip] === 'undefined' && users[ip].visits > 60) {
        banned[ip] = Date.now()
        log('BANNED:'.yellow, ip)
      }
      log('FLOODER:'.red, ip)
      res.writeHead(503, {'Content-Type': 'text/html'})
      res.end('<h1>Service unavailable</h1>')
    } else {
      next()
    }
  }