Peter Frlicka wrote: > Hello. > > What does apache + php do if the user refreshes a page 10 times in a while > before the scripts finishes? do all 10 .php scripts finish or do the first > 9 get aborted? how can i solve the problem that when someone clicks a lot > on a link (always the same link) the server gets overloaded (because the > action taken in the script is somehow memory consuming). i need to ensure > a user (www) can run only one instance of a .php script.
Depends a great deal on the version of the browser/server/PHP you are running. If all goes well, PHP aborts when the user HTTP connection is closed which happens when Apache realizes the browser isn't listening any more, which happens when Apache tries to send some PHP data to the browser. Thus, in general, try sending out a "." and calling http://php.net/flush periodically so that the HTTP connection has some traffic to detect the failure of the connection so the lack of a connection will get detected by Apache and then PHP gets informed about it. If you are worried about somebody attacking your site this way, though, the root problem is not solvable within PHP. At a certain point, the reload attack won't even *REACH* the PHP stage, and they'll just be pounding on HTTP connections to Apache. If you want to solve this problem the "right" way, you need to look into "Denial Of Service" attack defenses. Be warned: At a certain level, there is almost *NOTHING* you can do to defend against a bandwidth-filling DOS attack. Your upstream bandwidth provider (ISP) has to filter out the traffic and track it back to the sender and get them (or their ISP, actually) to block it. Packets are packets, and systematically and surgically blocking only the ones you don't at the right choke-point to keep your bandwidth useful is non-trivial. Steve (?) Gibson has a rather amusing (in a tabloid sort of way) article about this at grc.com NOTE: This guys is generally the laughingstock of the security experts for his media-whore tactics. -- Like music? http://l-i-e.com/artists.htm -- PHP General Mailing List (http://www.php.net/) To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] To contact the list administrators, e-mail: [EMAIL PROTECTED]
