Script to stop robot submissions?

Hi,

Can anyone point me in the direction of a script that will stop robots
from making multiple submissions to forms that we have on our site (20
to 30 in less than a minute), I was thinking of something like the ones
I have seen where yor have to enter a series of characters that are
displayed as a graphic. I have done a search but not found anything
(probably asking the wrong questions).

Thanks

Gerald

> Hi,
>
> Can anyone point me in the direction of a script that will stop robots
> from making multiple submissions to forms that we have on our site (20 to
> 30 in less than a minute), I was thinking of something like the ones I
> have seen where yor have to enter a series of characters that are
> displayed as a graphic. I have done a search but not found anything
> (probably asking the wrong questions).
>
To make the pic with the random character you can use the script below

<?php
$random = rand(100000, 999999);

header("Content-type: image/png");
$im = @imagecreate(500, 25)
or die("Cannot Initialize new GD image stream");
$background_color = imagecolorallocate($im, 250, 250, 250);
$text_color = imagecolorallocate($im, 233, 14, 91);
imagestring($im, 5, 5, 5, "$random", $text_color);
imagegif($im);
imagedestroy($im);
?>

The $random value you can also store in your mysql database to verify the
form.

Martijn

On Sun, 27 Mar 2005 17:14:47 +0200, "RotterdamStudents"
<NOSPAMnewsNOSPAM@MAPSONcistron.nederland> wrote:

>> Can anyone point me in the direction of a script that will stop robots
>> from making multiple submissions to forms that we have on our site (20 to
>> 30 in less than a minute), I was thinking of something like the ones I
>> have seen where yor have to enter a series of characters that are
>> displayed as a graphic. I have done a search but not found anything
>> (probably asking the wrong questions).
>>
>To make the pic with the random character you can use the script below
>
><?php
>$random = rand(100000, 999999);
>
>header("Content-type: image/png");
>$im = @imagecreate(500, 25)
> or die("Cannot Initialize new GD image stream");
>$background_color = imagecolorallocate($im, 250, 250, 250);
>$text_color = imagecolorallocate($im, 233, 14, 91);
>imagestring($im, 5, 5, 5, "$random", $text_color);
>imagegif($im);
>imagedestroy($im);
>?>
>
>The $random value you can also store in your mysql database to verify the
>form.

That would stop casual downloads, but wouldn't stop a determined bot author
since it's using an easily recognisable and consistent font.

--
Andy Hassall / <andy@andyh.co.uk> / <http://www.andyh.co.uk>
<http://www.andyhsoftware.co.uk/space> Space: disk usage analysis tool

You can have the letters large and different color. Then put a grey mesh of
thin lines over. You can stretch the picture x or y axis easly with PHP too
changing the letter thikness. Also you can use several fonts together.

Perhaps you'd like to hire me, I could do it in two days.


"Andy Hassall" <andy@andyh.co.uk> wrote in message
news:oumd415gqkfgi3qvj2tn4tudetu69ejj5l@4ax.com...
> On Sun, 27 Mar 2005 17:14:47 +0200, "RotterdamStudents"
> <NOSPAMnewsNOSPAM@MAPSONcistron.nederland> wrote:
>
>>> Can anyone point me in the direction of a script that will stop robots
>>> from making multiple submissions to forms that we have on our site (20
>>> to
>>> 30 in less than a minute), I was thinking of something like the ones I
>>> have seen where yor have to enter a series of characters that are
>>> displayed as a graphic. I have done a search but not found anything
>>> (probably asking the wrong questions).
>>>
>>To make the pic with the random character you can use the script below
>>
>><?php
>>$random = rand(100000, 999999);
>>
>>header("Content-type: image/png");
>>$im = @imagecreate(500, 25)
>> or die("Cannot Initialize new GD image stream");
>>$background_color = imagecolorallocate($im, 250, 250, 250);
>>$text_color = imagecolorallocate($im, 233, 14, 91);
>>imagestring($im, 5, 5, 5, "$random", $text_color);
>>imagegif($im);
>>imagedestroy($im);
>>?>
>>
>>The $random value you can also store in your mysql database to verify the
>>form.
>
> That would stop casual downloads, but wouldn't stop a determined bot
> author
> since it's using an easily recognisable and consistent font.
>
> --
> Andy Hassall / <andy@andyh.co.uk> / <http://www.andyh.co.uk>
> <http://www.andyhsoftware.co.uk/space> Space: disk usage analysis tool

On Tue, 05 Apr 2005 03:36:43 GMT, "Hello" <no-emai@sorry.com> wrote:

>> That would stop casual downloads, but wouldn't stop a determined bot
>> author
>> since it's using an easily recognisable and consistent font.
>
>You can have the letters large and different color. Then put a grey mesh of
>thin lines over. You can stretch the picture x or y axis easly with PHP too
>changing the letter thikness. Also you can use several fonts together.

Yes, that's the point. This is called a "CAPTCHA".

>Perhaps you'd like to hire me, I could do it in two days.

Or to save time and money and use one of the many free bits of code already
available. e.g. http://pear.php.net/package/Text_CAPTCHA#results

--
Andy Hassall / <andy@andyh.co.uk> / <http://www.andyh.co.uk>
<http://www.andyhsoftware.co.uk/space> Space: disk usage analysis tool