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Uncaptcha.Timer.3kaya

NAME

Uncaptcha::Timer - A time-based filter

SYNOPSIS

Uncaptcha::Timer< >

= Timer(String varname,Int mindelay,Int maxdelay)

DESCRIPTION

The logic behind this filter is described in a UseNet post by its inventor Ben Bacarisse in the message 87abj0fbpy.fsf@bsb.me.uk

varname is the variable name that will be used to send the timing state information (the information will be encrypted to prevent tampering). You can use any non-empty value for this provided that it is not otherwise used in the form.

mindelay is the minimum delay in seconds between the form being created and the user submitting it. This should be not be too large, or genuine fast users of the form may be blocked. If this value is negative, no requests will be blocked for being too fast.

maxdelay is the maximum delay in seconds between the form being created and the user submitting it. This aims to prevent the 'distributed' attacks where one hijacked computer obtains the form and places it into a queue, and another hijacked computer takes it from the queue several hours later and submits it. The delay should not be too small, however, especially for complex forms. If this value is negative, all requests will be blocked.

You should always redisplay a form that fails this check, as genuine users may also trigger this check on rare occasions (or if you have set the delays too harshly).

 // in the form generating function
     enableTimer(fieldset,myTimer);
 
 // in the form handling function
     if (checkTimer(myTimer)) {
         // process the form or do further checks
     } else {
         // give an error message, redisplay the form.
     }
 
 // myTimer (sample values only - do not use!)
 Timer myTimer = Timer("myvarname",20,10000);

AUTHORS

Kaya standard library by Edwin Brady, Chris Morris and others (kaya@kayalang.org). For further information see http://kayalang.org/

LICENSE

The Kaya standard library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License (version 2.1 or any later version) as published by the Free Software Foundation.

RELATED

Uncaptcha.checkTimer(3kaya)

Uncaptcha.enableTimer(3kaya)