# Sub-dependencies

You can create dependencies that have **sub-dependencies**.

They can be as **deep** as you need them to be.

**FastAPI** will take care of solving them.

## First dependency "dependable"

You could create a first dependency ("dependable") like:

{* ../../docs_src/dependencies/tutorial005_an_py310.py hl[8:9] *}

It declares an optional query parameter `q` as a `str`, and then it just returns it.

下图显示的是主应用 API 文档，只包括其自有的*路径操作*。

<img src="/img/tutorial/sub-applications/image01.png">

然后查看子应用文档 <a href="http://127.0.0.1:8000/subapi/docs" class="external-link" target="_blank">http://127.0.0.1:8000/subapi/docs。</a>

下图显示的是子应用的 API 文档，也是只包括其自有的*路径操作*，所有这些路径操作都在 `/subapi` 子路径前缀下。

<img src="/img/tutorial/sub-applications/image02.png">

两个用户界面都可以正常运行，因为浏览器能够与每个指定的应用或子应用会话。

### 技术细节：`root_path`

<img src="/img/tutorial/sub-applications/image01.png">

و سپس اسناد زیر برنامه را در آدرس <a href="http://127.0.0.1:8000/subapi/docs" class="external-link" target="_blank">http://127.0.0.1:8000/subapi/docs</a>. باز کنید.

اسناد API خودکار برای زیر برنامه را خواهید دید، که فقط شامل path operations خود می شود، همه در زیر مسیر `/subapi` قرار دارند:

<img src="/img/tutorial/sub-applications/image02.png">

### Sub-application

Then, create your sub-application, and its *path operations*.

This sub-application is just another standard FastAPI application, but this is the one that will be "mounted":

{* ../../docs_src/sub_applications/tutorial001.py hl[11, 14:16] *}

### Mount the sub-application

In your top-level application, `app`, mount the sub-application, `subapi`.

Sie sehen die automatische API-Dokumentation für die Hauptanwendung, welche nur deren eigene _Pfadoperationen_ anzeigt:

<img src="/img/tutorial/sub-applications/image01.png">

Öffnen Sie dann die Dokumentation für die Unteranwendung unter <a href="http://127.0.0.1:8000/subapi/docs" class="external-link" target="_blank">http://127.0.0.1:8000/subapi/docs</a>.

### Aplicación de nivel superior

Primero, crea la aplicación principal de nivel superior de **FastAPI**, y sus *path operations*:

{* ../../docs_src/sub_applications/tutorial001.py hl[3, 6:8] *}

### Sub-aplicación

Luego, crea tu sub-aplicación, y sus *path operations*.

Esta sub-aplicación es solo otra aplicación estándar de FastAPI, pero es la que se "montará":

### Aplicação de nível superior

Primeiro, crie a aplicação principal, de nível superior, **FastAPI**, e suas *operações de rota*:

{* ../../docs_src/sub_applications/tutorial001.py hl[3,6:8] *}

### Sub-aplicação

Em seguida, crie sua sub-aplicação e suas *operações de rota*.

Essa sub-aplicação é apenas outra aplicação FastAPI padrão, mas esta é a que será "montada":

Sebastián Ramírez <******@****.***> 1731896744 +0100

# Sub-dependencias

Puedes crear dependencias que tengan **sub-dependencias**.

Pueden ser tan **profundas** como necesites.

**FastAPI** se encargará de resolverlas.

## Primera dependencia "dependable"

Podrías crear una primera dependencia ("dependable") así:

{* ../../docs_src/dependencies/tutorial005_an_py310.py hl[8:9] *}

Declara un parámetro de query opcional `q` como un `str`, y luego simplemente lo devuelve.

👆 🔜 👀 🏧 🛠️ 🩺 👑 📱, 🔌 🕴 🚮 👍 _➡ 🛠️_:

<img src="/img/tutorial/sub-applications/image01.png">

&amp; ⤴️, 📂 🩺 🎧-🈸, <a href="http://127.0.0.1:8000/subapi/docs" class="external-link" target="_blank">http://127.0.0.1:8000/subapi/docs</a>.

👆 🔜 👀 🏧 🛠️ 🩺 🎧-🈸, ✅ 🕴 🚮 👍 _➡ 🛠️_, 🌐 🔽 ☑ 🎧-➡ 🔡 `/subapi`:

<img src="/img/tutorial/sub-applications/image02.png">