CAPTCHA and page caching

Hi

Drupal version: 5.3
Captcha module version: 5.x-3.1

The current version of Captcha doesnot work with Page cache enabled. This could be a big disadvantage in a large site with many pages. To resolve the same and cache the page content we could apply the below patch.

common.inc

function drupal_page_footer() {
+ //To enable page cache
+ global $user;
+ if(arg(0) == 'node' && is_numeric(arg(1)) && !$user->uid ){
+ $GLOBALS['conf']['cache'] = TRUE; //Cache this page
+ }
if (variable_get('cache', 0)) {
page_set_cache();
}
module_invoke_all('exit');
}

image_captcha.module

function image_captcha_image($seed=NULL) {
+ global $user;
if (!$seed) {
return;
}
// get the code to draw from $_SESSION
$code = $_SESSION['image_captcha'][$seed];
+ if(is_null($code) && $user->uid == 0){
+ $newseed = mt_rand();
+ +// regenerate a CAPTCHA code
+ $allowed_chars = _image_captcha_utf8_split(variable_get('image_captcha_image_allowed_chars', IMAGE_CAPTCHA_ALLOWED_CHARACTERS));
+ $code_length = (int)variable_get('image_captcha_code_length', 5);
+ $code = '';
+ for ($i = 0; $i < $code_length; $i++) {
+ $code .= $allowed_chars[array_rand($allowed_chars)];
+ }
+ $_SESSION['captcha'] = array();//to avoid "cookie enable error"
+ $_SESSION['image_captcha'][$newseed] = $code;
+ }

// unset the code from $_SESSION to prevent rerendering the CAPTCHA
+ if($user->uid !=0 ) {
unset($_SESSION['image_captcha'][$seed]);
+ }
// only generate an image if there is an code

We could furthur enhance and work towards removing session for anonymous user entirely and cache the captcha along with the page cache, refersh it only when used. Any suggestions.

Thanks