When you present the user with the submission form, create a unique ID, based on several factors, such as the current time, random numbers, user name, or anything else. Bury that id into a hidden field. When the submit button is hit the first time, look at that ID, save the message, and mark that that ID has been used already. If they hit submit again, check to see if the ID has been used already and if so, do nothing.
If you have a database, saving that ID is easy enough; if you are using flat files, just write each id to a file, one per line, and you can easily read and check those IDs that have already been entered.
Dr. Michael K. Neylon - mneylon-pm@masemware.com
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"You've left the lens cap of your mind on again, Pinky" - The Brain
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When you generate your form to submit a new posting, include a unique serial number as a hidden field, and store it on a database on server side.
When the response is submitted, check for the
serial number, and if it's absent or already used, then redirect to the form
again. If it hasn't been used, process the form and delete the serial number
from your database.
Hmm. That sounds like a good idea for a column. {grin} I've put it in the to-do
bucket.
-- Randal L. Schwartz, Perl hacker | [reply] |
I got a message board in my web site and currently I've been having the following problem...
For dealing with miscreants, Philip Greenspun suggests a subtle denial-of-service counter-attack. This
this chapter of Philip and Alex's Guide to Web Publishing, and search for Microsoft Helps Defend Against Bozos.
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Well, all of those solutions are fine, but this one takes the strain off the server's side. It uses JavaScript, and should be relatively easy to follow.
Here is the JavaScript portion:
var flag = 0;
function StopSubmit() {
if(!flag) { flag++; return 1; }
return 0;
}
And here is the form portion (you need to add the method and action parts):
<form onSubmit="return StopSubmit();">
The 15 year old, freshman programmer,
Stephen Rawls | [reply]
[d/l]
[select] |
Hi.
Thanks for all of your answers!! :)
I think i'm gonna use the javascript version for now, since it doesn't deal with the server. i'll keep all of them in mind though :)
anyway... i'm 15 as well!! if anyone cares my email's: ralph.a.ch@fibertel.com.ar .
Thanks,
Ralph :)
www.argenteen.com | [reply] |
Why not just take an md5 checksum of message and before you add it to the database, check to see if that checksum already exists?...
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