Prevents duplicate Gravity Forms submissions caused by the same POST request sent more than once.
Gravity Forms already has some built-in duplicate submission prevention techniques, including the No Duplicates setting for a field in your form, preventing the same field value from being used multiple times for the same form. Using this setting is a rock solid approach to avoid duplicate submissions, but it requires having a field in your form that you can consider as a source of unique data per submission.
This add-on helps using the same idea, without requiring having a field to enable the No Duplicates setting, by dynamically adding a hidden input with a random token to the form, and checks the POST request received for this token value to prevent duplicate submissions.
This will stop identical POST requests from being accepted for entry creation, like the ones that some browsers will send when the browser back or refresh buttons are clicked or when browser tabs are restored in mobile devices.
To put in another way, the add-on is intended to block automated resend of the same POST request data, it doesn’t block submissions voluntarily initiated by the visitor.
Optionally, you can customize the duplicate submission message shown to users from the settings page or using a filter (see the FAQ).
The add-on functionality relies on a random token generated dynamically, so for obvious reasons caching the page where your form is embedded would prevent the add-on from working as expected. This is not a limitation of the add-on but the expected if you’re serving a static version of your page, which is the only reason to cache a page, you shouldn’t never cache pages where you expect dynamic data.
Most caching plugins provide you a way to exclude URLs from cache, this is for a reason, use it.
There are some web hosting providers using cache at server level and not providing their customers with an interface to exclude URLs from cache (e.g. WP Engine, Kinsta, …), you can still ask your host support staff to add the exclusion for you.
You can also use Fresh Forms for automated cache exclusion if you use any of the embedding methods and caching plugins supported (see Fresh Forms description for more details).
Yes. You can do this from the Forms > Settings > GF No Duplicates settings page. Or using the gnd_duplicate_submission_message filter. See the example below:
add_filter( 'gnd_duplicate_submission_message', function( $message, $form ) { $message = 'Your custom text goes here'; return $message; }, 10, 2 );
Using the filter will override the default message and any custom message that you may have added in the settings page.