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August 30, 2008 03:24am pdt
 
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How to validate source of posted form data

Tags: 0, how, random
I'm working on a site that generates random discounts for products, and need to make sure that any random discount information that gets passed to cart.asp actully comes from my site (& isn't spoofed by someone else).

I'm currently using

randDiscount = request.Form("randDiscount")
If Instr(Request.ServerVariables("HTTP_Referer"), "http://www.mysite.com/")>0 Then
     randDiscount = randDiscount/100
     Else
     randDiscount = 0
End if

This works, but if a user spoofs or disables the referrer information in their browser, they won't get the discount they're supposed to.  I guess I could treat this as a slap on the wrist for coming to my site without telling me where they came from, but they are my customers & I'd rather not irritate them.

Any ideas?

Thanks
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Question Stats
Zone: Web Development
Question Asked By: eusebius
Solution Provided By: rg20
Participating Experts: 3
Solution Grade: A
Views: 0
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