// 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":130,"count":2,"description":"","link":"https:\/\/one-foodie.com\/area\/gaienmae\/","name":"\u5916\u82d1\u524d","slug":"gaienmae","taxonomy":"area","parent":46,"meta":[],"_links":{"self":[{"href":"https:\/\/one-foodie.com\/wp-json\/wp\/v2\/area\/130"}],"collection":[{"href":"https:\/\/one-foodie.com\/wp-json\/wp\/v2\/area"}],"about":[{"href":"https:\/\/one-foodie.com\/wp-json\/wp\/v2\/taxonomies\/area"}],"up":[{"embeddable":true,"href":"https:\/\/one-foodie.com\/wp-json\/wp\/v2\/area\/46"}],"wp:post_type":[{"href":"https:\/\/one-foodie.com\/wp-json\/wp\/v2\/posts?area=130"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}