Regarding Contact Form 7, it’s possible to have it working, but you’ll have to get your hands dirty in the code because they don’t have action hooks in the right places (the filter one is not standard but easy to apply a fix for).
On wp-content/plugins/contact-form-7/includes/classes.php, to show the captcha, you can simply add the following code:
ob_start();
do_action( 'wpcf7_custom_visualcaptcha' );
$html .= ob_get_clean();
Right on the line after or before $html .= $this->form_elements(); (it will show the captcha in an awkward place, before the form or after the send button, but to fix that, you’d have to create a deep integration with shortcode for cf7 — not impossible, just needs coding).
That will show visualCaptcha, but not use it for validation.
To validate it, you need to add the following code to wp-content/plugins/visualcaptcha/visualcaptcha.php:
// Special condition for Contact Form 7
if ( strpos( current_filter(), 'wpcf7_' ) !== false ) {
if ( !empty( $arg1 ) ) {
if ( is_array( $arg1 ) && isset( $arg1[ 'valid' ] ) && !empty( $arg1[ 'valid' ] ) ) {
$arg1[ 'valid' ] = false;
$arg1[ 'reason' ] = 'You failed the human verification test. Please go back and try again.';
return $arg1;
}
}
}
Right after
// Special condition for comments
if ( strpos( current_filter(), 'comment' ) !== false ) {
if ( !empty( $arg1 ) ) {
if ( is_array( $arg1 ) && isset( $arg1[ 'comment_post_ID' ] ) && !empty( $arg1[ 'comment_post_ID' ] ) ) {
wp_die( __( 'ERROR: You failed the human verification test. Please go back and try again.', 'visualcaptcha' ) );
}
}
}
Then, for visualCaptcha admin, add a Hook, with the following settings:
Option Name: Contact Form 7
Display Hook: wpcf7_custom_captcha
Validation Hook: wpcf7_validate
Also note that should either plugin be updated, these code changes will be lost.
If enough requests come into github, we will look into making this integration easier.
It is possible and demonstrated here.
Hope that helps.
Regarding Gravity Form, it seems it’s a paid plugin, so I couldn’t test it, anyway, the example above should be enough to help, in case their hooks don’t support the standards we’re looking for (used in default wordpress comments, login, register forms).
