* _مسیر_ `/items/{item_id}` شامل  <abbr title="Query Parameter">_پارامتر پرسمان_</abbr> اختیاری `q` از نوع `str` است.

### مستندات API تعاملی

حال به آدرس  <a href="http://127.0.0.1:8000/docs" class="external-link" target="_blank">http://127.0.0.1:8000/docs</a> بروید.

مستندات API تعاملی (ایجاد شده به کمک <a href="https://github.com/swagger-api/swagger-ui" class="external-link" target="_blank">Swagger UI</a>) را مشاهده خواهید کرد:

///

## Benutzerdefinierte Header

Beachten Sie, dass benutzerdefinierte proprietäre Header <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers" class="external-link" target="_blank">mittels des Präfix 'X-'</a> hinzugefügt werden können.

 *
 * The current implementation does not address any of:
 *  - Async DNS split by IP class
 *  - Stateful handling of connectivity results
 *  - The prioritisation of addresses
 *
 * https://datatracker.ietf.org/doc/html/rfc8305#section-4
 */
internal fun reorderForHappyEyeballs(addresses: List<InetAddress>): List<InetAddress> {
  if (addresses.size < 2) {
    return addresses
  }

/// info

💡 🌖 🔃 <a href="https://docs.pydantic.dev/" class="external-link" target="_blank">Pydantic, ✅ 🚮 🩺</a>.

///

**FastAPI** 🌐 ⚓️ 🔛 Pydantic.

👆 🔜 👀 📚 🌅 🌐 👉 💡 [🔰 - 👩‍💻 🦮](tutorial/index.md){.internal-link target=_blank}.

/// tip

If you open a GitHub Issue, here is our policy:

1.  It must be a bug/performance issue or a feature request or a build issue or
    a documentation issue (for small doc fixes please send a PR instead).
1.  Make sure the Issue Template is filled out.
1.  The issue should be related to the repo it is created in.

**Here's why we have this policy:** We want to focus on the work that benefits
the whole community, e.g., fixing bugs and adding features. Individual support

* `routes`: 📇 🛣, 👫 🔠 ® *➡ 🛠️*. 👫 ✊ ⚪️➡️ `app.routes`.

## 🔑 🔢

⚙️ ℹ 🔛, 👆 💪 ⚙️ 🎏 🚙 🔢 🏗 🗄 🔗 & 🔐 🔠 🍕 👈 👆 💪.

🖼, ➡️ 🚮 <a href="https://github.com/Rebilly/ReDoc/blob/master/docs/redoc-vendor-extensions.md#x-logo" class="external-link" target="_blank">📄 🗄 ↔ 🔌 🛃 🔱</a>.

### 😐 **FastAPI**

🥇, ✍ 🌐 👆 **FastAPI** 🈸 🛎:

{* ../../docs_src/extending_openapi/tutorial001.py hl[1,4,7:9] *}

 * href="https://www.javadoc.io/doc/com.github.ben-manes.caffeine/caffeine/latest/com.github.benmanes.caffeine/com/github/benmanes/caffeine/cache/Cache.html">{@code
 * Cache}</a>, <a
 * href="https://www.javadoc.io/doc/com.github.ben-manes.caffeine/caffeine/latest/com.github.benmanes.caffeine/com/github/benmanes/caffeine/cache/LoadingCache.html">{@code
 * LoadingCache}</a>, <a

Ví dụ:

* <a href="https://code.visualstudio.com/docs/python/environments#_select-and-activate-an-environment" class="external-link" target="_blank">VS Code</a>
* <a href="https://www.jetbrains.com/help/pycharm/creating-virtual-environment.html" class="external-link" target="_blank">PyCharm</a>

///

## Headers Personalizados

Ten en cuenta que los headers propietarios personalizados se pueden agregar <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers" class="external-link" target="_blank">usando el prefijo 'X-'</a>.

{* ../../docs_src/header_param_models/tutorial001_an_py310.py hl[9:14,18] *}

**FastAPI**는 요청에서 받은 **헤더**에서 **각 필드**에 대한 데이터를 **추출**하고 정의한 Pydantic 모델을 줍니다.

## 문서 확인하기

문서 UI `/docs`에서 필요한 헤더를 볼 수 있습니다:

<div class="screenshot">
<img src="/img/tutorial/header-param-models/image01.png">
</div>

## 추가 헤더 금지하기

일부 특별한 사용 사례(흔하지는 않겠지만)에서는 수신하려는 헤더를 **제한**할 수 있습니다.