private PacCredentialType credentialType;
    private PacSignature serverSignature;
    private PacSignature kdcSignature;

    /**
     * Constructs and validates a PAC from raw data using provided Kerberos keys.
     * @param data the raw PAC data bytes
     * @param keys map of Kerberos keys for signature validation
     * @throws PACDecodingException if the PAC data is malformed or signature validation fails

                .append("\", arch: \"")
                .append(Os.OS_ARCH)
                .append("\", family: \"")
                .append(Os.OS_FAMILY)
                .append('\"');
        // Add process information using modern Java API
        if (commandLine != null) {
            version.append(ls).append("Command line: ").append(commandLine);
        }
        if (terminal != null) {

query_extractor(["query_extractor"])
query_or_cookie_extractor(["query_or_cookie_extractor"])

read_query["/items/"]

query_extractor --> query_or_cookie_extractor --> read_query
```

## 같은 의존성을 여러 번 사용하기 { #using-the-same-dependency-multiple-times }

같은 *경로 처리*에 대해 의존성 중 하나가 여러 번 선언되는 경우(예: 여러 의존성이 공통 하위 의존성을 갖는 경우), **FastAPI**는 그 하위 의존성을 요청당 한 번만 호출해야 한다는 것을 알고 있습니다.

# 使用 Dataclasses { #using-dataclasses }

FastAPI 建立在 **Pydantic** 之上，我之前示範過如何使用 Pydantic 模型來宣告請求與回應。

但 FastAPI 也同樣支援以相同方式使用 [`dataclasses`](https://docs.python.org/3/library/dataclasses.html)：

{* ../../docs_src/dataclasses_/tutorial001_py310.py hl[1,6:11,18:19] *}

這之所以可行，要感謝 **Pydantic**，因為它 [內建支援 `dataclasses`](https://docs.pydantic.dev/latest/concepts/dataclasses/#use-of-stdlib-dataclasses-with-basemodel)。

graph TB

query_extractor(["query_extractor"])
query_or_cookie_extractor(["query_or_cookie_extractor"])

read_query["/items/"]

query_extractor --> query_or_cookie_extractor --> read_query
```

## 多次使用同一個相依項 { #using-the-same-dependency-multiple-times }

如果你的某個相依項在同一個路徑操作中被宣告了多次，例如多個相依共用同一個子相依，**FastAPI** 會知道只需在每次請求中呼叫該子相依一次。

它會把回傳值儲存在一個 <dfn title="用來儲存已計算/產生之值的工具／系統，以便重複使用而不必再次計算。">「快取」</dfn> 中，並在該次請求中傳遞給所有需要它的「相依者」，而不是為同一個請求多次呼叫相同的相依項。

Birçok mesaj gönderebilir (ve alabilirsiniz):

<img src="/img/tutorial/websockets/image04.png">

Ve hepsinde aynı WebSocket bağlantısı kullanılacaktır.

## `Depends` ve Diğerlerini Kullanma { #using-depends-and-others }

WebSocket endpoint'lerinde `fastapi` içinden import edip şunları kullanabilirsiniz:

* `Depends`
* `Security`
* `Cookie`
* `Header`
* `Path`
* `Query`

import jakarta.servlet.http.HttpServletResponse;

/**
 * SPNEGO (Security Provider Negotiation Protocol) authenticator implementation.
 *
 * This class provides Single Sign-On (SSO) authentication using the SPNEGO protocol,
 * which is commonly used for Kerberos-based authentication in Windows environments.
 * It handles the negotiation between client and server to establish a secure

      <span style="background-color:#007166"><font color="#D3D7CF"> app </font></span>  Using import string: <font color="#3465A4">main:app</font>

    }
    throw new AssertionError();
  }

  @GwtIncompatible // TODO
  private static BigInteger sqrtFloor(BigInteger x) {
    /*
     * Adapted from Hacker's Delight, Figure 11-1.
     *
     * Using DoubleUtils.bigToDouble, getting a double approximation of x is extremely fast, and
     * then we can get a double approximation of the square root. Then, we iteratively improve this

  }

  /**
   * Returns an {@link Optional} containing the first element in this fluent iterable that satisfies
   * the given predicate, if such an element exists.
   *
   * <p><b>Warning:</b> avoid using a {@code predicate} that matches {@code null}. If {@code null}
   * is matched in this fluent iterable, a {@link NullPointerException} will be thrown.
   *