所以，即使上面的程式碼沒有明確使用 Pydantic，FastAPI 仍會使用 Pydantic 將那些標準的 dataclass 轉換為 Pydantic 版本的 dataclass。

而且當然一樣支援：

- 資料驗證
- 資料序列化
- 資料文件化等

它的運作方式與 Pydantic 模型相同；實際上，底層就是透過 Pydantic 達成的。

/// info

請記得，dataclass 無法做到 Pydantic 模型能做的一切。

所以你可能仍然需要使用 Pydantic 模型。

但如果你手邊剛好有一堆 dataclass，這是個不錯的小技巧，可以用來用 FastAPI 驅動一個 Web API。🤓

///

## 在 `response_model` 中使用 Dataclasses { #dataclasses-in-response-model }

    - 如果使用者沒有提供查詢 `q`，我們就使用先前儲存在 cookie 中的最後一次查詢值。

## 使用相依項 { #use-the-dependency }

然後我們可以這樣使用這個相依項：

{* ../../docs_src/dependencies/tutorial005_an_py310.py hl[23] *}

/// info

注意，在路徑操作函式中我們只宣告了一個相依項 `query_or_cookie_extractor`。

但 **FastAPI** 會知道它必須先解析 `query_extractor`，在呼叫 `query_or_cookie_extractor` 時把其結果傳入。

///

```mermaid
graph TB

query_extractor(["query_extractor"])

    boolean threadStarted = false;
    try {
      finalizerStarter.startFinalizer(FinalizableReference.class, queue, frqRef);
      threadStarted = true;
    } catch (Throwable t) {
      logger.log(
          Level.INFO,
          "Failed to start reference finalizer thread."
              + " Reference cleanup will only occur when new references are created.",
          t);
    }

    this.threadStarted = threadStarted;
  }

В таком случае вы можете отключить эту функциональность в **FastAPI** с помощью параметра `separate_input_output_schemas=False`.

/// info | Информация

Поддержка `separate_input_output_schemas` появилась в FastAPI `0.102.0`. 🤓

///

{* ../../docs_src/separate_openapi_schemas/tutorial002_py310.py hl[10] *}

			if !osIsNotExist(err) && !osIsPermission(err) {
				return nil, err
			}
			continue
		}
		data, _ = json.Marshal(cfg)
		break
	}
	if osIsPermission(err) {
		logger.Info("Older config found but is not readable %s, proceeding to read config from other places", err)
	}
	if osIsNotExist(err) || osIsPermission(err) || len(data) == 0 {
		data, err = readConfig(GlobalContext, objAPI, configFile)

 * 2.0 and the Server Side Public License, v 1; you may not use this file except
 * in compliance with, at your election, the Elastic License 2.0 or the Server
 * Side Public License, v 1.
 */
package org.elasticsearch.gradle.internal.info;

import org.elasticsearch.gradle.internal.BwcVersions;
import org.gradle.api.JavaVersion;
import org.gradle.api.provider.Provider;

import java.io.File;
import java.lang.reflect.Modifier;

   * converts that into a <a
   * href="https://docs.oracle.com/en/java/javase/25/docs/api/java.base/java/util/concurrent/locks/Condition.html#implementation-considerations-heading">spurious
   * wakeup</a>. This means that resulting wait is not "uninterruptible" in the normal sense of
   * {@link Uninterruptibles}. Still, this method allows callers to write <a

Burada `UserIn` adında bir model declare ediyoruz; bu model plaintext bir password içerecek:

{* ../../docs_src/response_model/tutorial002_py310.py hl[7,9] *}

/// info | Bilgi

`EmailStr` kullanmak için önce [`email-validator`](https://github.com/JoshData/python-email-validator) paketini kurun.

            Path pomPath = entry.getKey();
            Document pomDocument = entry.getValue();
            processedPoms.add(pomPath);

            context.info(pomPath + " (checking for Maven 4 compatibility issues)");
            context.indent();

            try {
                boolean hasIssues = false;

                // Apply all compatibility fixes

### Uygulamayı Çalıştırma { #run-the-app }

Uygulamayı çalıştırabilirsiniz:

<div class="termy">

```console
$ fastapi dev

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
```

</div>