// 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;
}{"code":"rest_no_route","message":"URL \u3068\u30ea\u30af\u30a8\u30b9\u30c8\u30e1\u30bd\u30c3\u30c9\u306b\u4e00\u81f4\u3059\u308b\u30eb\u30fc\u30c8\u304c\u898b\u3064\u304b\u308a\u307e\u305b\u3093\u3067\u3057\u305f\u3002","data":{"status":404}}