Re: apache+php overloading when user clicks many times on the same link

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. > > Peter Frlicka See http://www.php.net/manual/en/features.connection-handling.php I'm worried about why the user is clicking so much. If your connection/processing really is going to take a long time you could consider sending them the first bit of your page as quickly as possible using "flush()". That will take away any buttons/links they've clicked on (but not Refresh), and at least make them feel something is happening! However multiple clicking is a general problem with no great solutions. It's a particularly important issue for on-line E-commerce applications when it is not only vital that the php script complete but also that it should not be repeated. For that you almost have to use a database to record "transactions" (or at least the session variables which identify a "transaction"). I typically do the following : 1. set ignore_user_abort 2. check to see if we have a record of this transaction, if we do check to see if it is complete. If it's complete take them to a results/end page, if it's not complete take them to a holding page with an automatic META-REFRESH to the same url. 3. if we have no record of the transaction, create one, do the work, mark the transaction as complete and show them the results/end page. If the user only clicks once, everything proceeds smoothly and they get their results page as normal. If the user clicks two or more times they go to a "holding" page with an automatic refresh which keeps showing the same holding page until the first script completes and the next refresh takes them to the results. This is basically a safe approach but it's significant work unless you really need it! George