Got an internet lesson today

When you make a web application, be sure that you don’t allow your links to do anything that changes the state of the system.

I just accessed my mjg.md website and found that all the xqueries had been erased, at first I thought i might be some malicious user. So I checked the HTTP logs and here is what I found:

mjg.md 66.249.65.80 — — [11/Jan/2005:15:19:14 -0600] “GET /deletexquery.jsp?id=17 HTTP/1.1” 200 312 Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html) -
…

Ouch. GoogleBot very efficienctly erased all the xqueries that I had registered… Oh well. Back to the drawing board I guess. It’s too bad, because a simple link is exactly what I want to make the interface as simple to use as possible.