Captcha

[westmatrix99]

How to create a captcha, have tried lines of captcha code but images are always blank.
So how do I do this?

[vinyl-junkie]

Are you trying to incorporate someone else's captcha code into one of your existing web pages, or what? Post your code. It's impossible to offer you any real help without that.

[westmatrix99]

I am using a tutorial and it's all blank.

[vinyl-junkie]

Did you download code from the tutorial? How about posting a link to the tutorial you're using?

[JohnDubya]

Originally Posted by westmatrix99

I am using a tutorial and it's all blank.

Hello there! It's always good to post as much information as is possible for each situation. If there is code that has a problem, post it. If you're using a tutorial, post it. If there's a page we can look at that isn't showing up correctly, post it and the code it uses...etc. etc. Be as descriptive as possible! Good luck!

[westmatrix99]

The tutorial is on this site:

http://codewalkers.com/tutorials/95/1.html

[rafiki]

PHP Code:

<?php
//Start the session so we can store what the code actually is.
session_start();

//Now lets use md5 to generate a totally random string
$md5 = md5(microtime() * mktime());

/*
We dont need a 32 character long string so we trim it down to 5
*/
$string = substr($md5,0,5);


/*
Now for the GD stuff, for ease of use lets create
 the image from a background image.
*/

$captcha = imagecreatefrompng("./captcha.png");

/*
Lets set the colours, the colour $line is used to generate lines.
 Using a blue misty colours. The colour codes are in RGB
*/

$black = imagecolorallocate($captcha, 0, 0, 0);
$line = imagecolorallocate($captcha,233,239,239);

/*
Now to make it a little bit harder for any bots to break, 
assuming they can break it so far. Lets add some lines
in (static lines) to attempt to make the bots life a little harder
*/
imageline($captcha,0,0,39,29,$line);
imageline($captcha,40,0,64,29,$line);
/*
Now for the all important writing of the randomly generated string to the image.
*/
imagestring($captcha, 5, 20, 10, $string, $black);


/*
Encrypt and store the key inside of a session
*/

$_SESSION['key'] = md5($string);

/*
Output the image
*/
header("Content-type: image/png");
imagepng($captcha);
?>

thats the code he is using, to save you all from multipages of code i compiled into easy view

[westmatrix99]

Cool thanks, will try to figure it out.

Cheers

[westmatrix99]

When I run it I get this error:

Fatal error: Call to undefined function imagecreatefrompng() in c:\Inetpub\wwwroot\usermail\untitled.php on line 19

This on line 19:

$captcha = imagecreatefrompng("./captcha.png");

Any idea?

[vinyl-junkie]

Have you read what the manual says about imagecreatefrompng? There are a couple of warnings about things which could cause this command to fail.

The easiest way to find out the settings on your server is to create a file with the following:

<?php
phpinfo();
?>

Upload that file to your server, run it, and check what the settings are for allow_url_fopen. That should be set to On.

[westmatrix99]

Yes it's on

[westmatrix99]

I ran this to test it

<?php
if (!function_exists('imagecreatefromjpeg')) { 
     echo 'imagecreatefromjpeg() exists.'; 
}  
?>

and it returns this:

imagecreatefromjpeg() exists.

[JohnDubya]

Your logic is looking to see if the function "imagecreatefromjpeg" does NOT exist (evident from the ! which means "NOT"), but your text is printing "exists." Do it like this:

PHP Code:

<?php
if (function_exists('imagecreatefromjpeg')) { 
     echo 'imagecreatefromjpeg() exists.'; 
} else {
     echo 'imagecreatefromjpeg() does not exist.';
}
?>

[westmatrix99]

I tried for all and got a good response but still get an error:

<?php
if (!function_exists('imagecreatefromjpeg')) {
echo 'imagecreatefromjpeg() exists.<br>';
}
if (!function_exists('imagecreatefromgif')) {
echo 'imagecreatefromgif() exists.<br>';
}
if (!function_exists('imagecreatefrompng')) {
echo 'imagecreatefrompng() exists.<br>';
}
?>

[Fumigator]

You don't have the GD library installed. You are confused as to what you are checking on those "if" statements-- you are saying if (NOT function_exists()) echo 'function exists!', so the fact they are all returning 'function exists' means they don't exist.