title: How to prevent excessive site visits (suspected screen scraping) from hackers?
body: <p>I have a website that has been hacked once to have it's database stolen. I think it was done by an automated process that simply accessed the visible website using a series of searches, in the style of 'give me all things beginning with AA', then 'with AB', then 'with AC' and so on. The reality is a little more complicated than this, but that illustrates the principal of the attack. I found the thief and am now taking steps against them, but I want to prevent more like this in the future.</p>
  
  <p>I thought there must be some ready made PHP (which I use) scripts out there. Something that for instance recorded the IP address of the last (say) 50 visitors and tracked the frequency of their requests over the last (say) 5 minutes. It would ban them for (say) 24 hours if they exceeded a certain threshold of requests. However to my amazement I can find no such class, library or example of code intended for this purpose, anywhere online.</p>
  
  <p>Am I missing a trick, or is there a solution here - like the one I imagine, or maybe an even simpler and more effective safeguard?</p>
  
  <p>Thanks.</p>