///

## 额外校验 { #additional-validation }

我们打算添加约束：即使 `q` 是可选的，但只要提供了该参数，**其长度不能超过 50 个字符**。

### 导入 `Query` 和 `Annotated` { #import-query-and-annotated }

为此，先导入：

- 从 `fastapi` 导入 `Query`
- 从 `typing` 导入 `Annotated`

{* ../../docs_src/query_params_str_validations/tutorial002_an_py310.py hl[1,3] *}

/// info | 信息

FastAPI 在 0.95.0 版本中添加了对 `Annotated` 的支持（并开始推荐使用）。

如果你的版本更旧，使用 `Annotated` 会报错。

    --hash=sha256:3afb05607b89aed0ffe25202399ee0867ad4d3cb4180d98aaf8eefa6a5f7d475 \
    --hash=sha256:b5b08f68937f138fe92f6c089b99f1e2da0ae56c52b78bf7075fd95420fd9a5a
    # via -r ci/official/requirements_updater/requirements.in
typing-extensions==4.14.1 \
    --hash=sha256:38b39f4aeeab64884ce9f74c94263ef78f3c22467c8724005483154c26648d36 \
    --hash=sha256:d1e1e3b58374dc93031d6eda2420a48ea44a36c2b4766a4fdeb3710755731d76
    # via

least 1024 bits. This behavior can be controlled with the `rsa1024min` setting.
Using `rsa1024min=0` restores the Go 1.23 behavior.

Go 1.24 introduced a mechanism for enabling platform specific Data Independent
Timing (DIT) modes in the [`crypto/subtle`](/pkg/crypto/subtle) package. This
mode can be enabled for an entire program with the `dataindependenttiming` setting.

`q`はオプショナルですが、もし値が渡されてきた場合には、**長さが50文字を超えないこと**を強制してみましょう。

### `Query` と `Annotated` のインポート { #import-query-and-annotated }

そのために、まずは以下をインポートします:

* `fastapi` から `Query`
* `typing` から `Annotated`

{* ../../docs_src/query_params_str_validations/tutorial002_an_py310.py hl[1,3] *}

/// info | 情報

FastAPI はバージョン 0.95.0 で `Annotated` のサポートを追加し（推奨し始め）ました。

古いバージョンの場合、`Annotated` を使おうとするとエラーになります。

    val requestBodyDelay = 250L
    val responseHeadersStartDelay = 250L
    val responseBodyStartDelay = 250L
    val responseBodyEndDelay = 250L

    // Warm up the client so the timing part of the test gets a pooled connection.
    server.enqueue(MockResponse())
    val warmUpCall =
      client.newCallWithListener(
        Request
          .Builder()
          .url(server.url("/"))

     *
     * <p>Note that the method will be called even upon an invocation of {@code tryLock()}. Although
     * {@code tryLock()} technically recovers from deadlock by eventually timing out, this behavior
     * is chosen based on the assumption that it is the application's wish to prohibit any cyclical
     * lock acquisitions.
     */
    void handlePotentialDeadlock(PotentialDeadlockException exception);

   * <p>This executor is appropriate for tasks that are lightweight and not deeply chained.
   * Inappropriate {@code directExecutor} usage can cause problems, and these problems can be
   * difficult to reproduce because they depend on timing. For example:
   *
   * <ul>
   *   <li>When a {@code ListenableFuture} listener is registered to run under {@code
   *       directExecutor}, the listener can execute in any of three possible threads:
   *       <ol>

   *
   * <p>The default implementation of this method in {@code AbstractFuture} does nothing. This is
   * intended for very lightweight cleanup work, for example, timing statistics or clearing fields.
   * If your task does anything heavier consider, just using a listener with an executor.
   *
   * @since 20.0
   */
  @ForOverride
  protected void afterDone() {}

* 🔥 Remove Python 3.9 specific files, no longer needed after updating translations. PR [#14931](https://github.com/fastapi/fastapi/pull/14931) by [@tiangolo](https://github.com/tiangolo).
* 📝 Update docs for JWT to prevent timing attacks. PR [#14908](https://github.com/fastapi/fastapi/pull/14908) by [@tiangolo](https://github.com/tiangolo).

### Translations

그 후 APIStar 서버가 더는 존재하지 않게 되고 Starlette가 만들어졌는데, 이는 그런 시스템을 위한 더 새롭고 더 나은 기반이었습니다. 이것이 **FastAPI**를 만들게 된 최종 영감이었습니다.

저는 **FastAPI**를 APIStar의 "정신적 후계자"로 생각합니다. 동시에, 이 모든 이전 도구들에서 배운 것들을 바탕으로 기능, typing 시스템, 그리고 다른 부분들을 개선하고 확장했습니다.

///

## **FastAPI**가 사용하는 것 { #used-by-fastapi }

### [Pydantic](https://docs.pydantic.dev/) { #pydantic }