// Contact Form7のお問い合せフォーム項目にひらがなが無ければ送信不可
add_filter('wpcf7_validate_textarea', 'wpcf7_validation_textarea_hiragana', 10, 2);
add_filter('wpcf7_validate_textarea*', 'wpcf7_validation_textarea_hiragana', 10, 2);
function wpcf7_validation_textarea_hiragana($result, $tag)
{
  $name = $tag['name'];
  $value = (isset($_POST[$name])) ? (string) $_POST[$name] : '';
  if ($value !== '' && !preg_match('/[ぁ-ん]/u', $value)) {
    $result['valid'] = false;
    $result['reason'] = array($name => 'エラー：こちらの内容は送信できません。');
  }
  return $result;
}{"id":1,"name":"Kyohei","url":"http:\/\/one-foodie.com","description":"","link":"https:\/\/one-foodie.com\/author\/taguchi\/","slug":"taguchi","avatar_urls":{"24":"https:\/\/secure.gravatar.com\/avatar\/afcbf3510cb155aa58184c91635a3d0f?s=24&d=mm&r=g","48":"https:\/\/secure.gravatar.com\/avatar\/afcbf3510cb155aa58184c91635a3d0f?s=48&d=mm&r=g","96":"https:\/\/secure.gravatar.com\/avatar\/afcbf3510cb155aa58184c91635a3d0f?s=96&d=mm&r=g"},"meta":[],"simple_local_avatar":null,"_links":{"self":[{"href":"https:\/\/one-foodie.com\/wp-json\/wp\/v2\/users\/1"}],"collection":[{"href":"https:\/\/one-foodie.com\/wp-json\/wp\/v2\/users"}]}}