Reply To: Adding Required Input Parameters for Custom Field

• John Huebner

• October 5, 2021 at 9:48 am

To do this you use an acf/validate_value filter.

add_filter('acf/validate_value/name=your_field_name', 'your_validate_function_name', 10, 4);
function your_validate_function_name($valid, $value, $field, $input_name) {
  if ($valid !== true) {
    return $valid;
  }
  if (strlen($value) < 8 // < 8 characters
      || preg_match('/^[A-Z]/', $value) // starts with a cap
      || !preg_match('/[A-Z]/, $value) // contains no caps
      || !preg_match('/[0-9]/', $value) // contains no numbers
      || !preg_match('/[0-9a-zA-Z]$/', $value) // ends is something other than a letter or number) {
    $valid = 'Value is not valid';
  }
  return $valid;
}