Add filter with which you can disable additional field validation

Use the post object instead

Define variable before passing to avoid error

Author: Jukka Rautanen

README.md

@@ -156,6 +156,25 @@ function my_email_thankyou( $return ) {
 }
 ```
 
+### Filter: wplf_disable_validate_additional_fields
+
+Dynamically generated fields are disabled by default. If you want to allow fields that are not set in the form to be submitted you can use this filter.
+
+#### Form specific hooks
+
+This filter supports form specific hooks:
+
+- `wplf_{form_id}_disable_validate_additional_fields`
+- `wplf_{form_slug}_disable_validate_additional_fields`
+
+These filters are only applied for the target form by ID or slug.
+
+Disabling additonal fields validation for all forms:
+
+```php
+add_filter( 'wplf_disable_validate_additional_fields' , __return_false );
+```
+
 ## Javascript API
 
 ### Client side callbacks

inc/wplf-form-validation.php

@@ -71,8 +71,21 @@ function wplf_validate_additional_fields( $return ) {
     return $return;
   }
 
+  // skip this validation if it is disabled with filter for this form
+  $form = get_post( intval( $_POST['_form_id'] ) );
+  // global disable
+  $disable_validation = false;
+  $disable_validation = apply_filters( 'wplf_disable_validate_additional_fields', $disable_validation );
+  // disable by form id
+  $disable_validation = apply_filters( "wplf_{$form->ID}_disable_validate_additional_fields", $disable_validation );
+  // disable by form slug
+  $disable_validation = apply_filters( "wplf_{$form->post_name}_disable_validate_additional_fields", $disable_validation );
+  if ( $disable_validation ) {
+    return $return;
+  }
+
   // get all fields from form
-  $form_fields = explode( ',', get_post_meta( $_POST['_form_id'], '_wplf_fields', true ) );
+  $form_fields = explode( ',', get_post_meta( $form->ID, '_wplf_fields', true ) );
 
   // add all default fields
   $default_fields = array( 'referrer', '_referrer_id', '_form_id' );