## First dependency "dependable"

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

//// tab | Python 3.10+

```Python hl_lines="8-9"
{!> ../../docs_src/dependencies/tutorial005_an_py310.py!}
```

////

//// tab | Python 3.9+

```Python hl_lines="8-9"
{!> ../../docs_src/dependencies/tutorial005_an_py39.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="9-10"

Sie könnten eine erste Abhängigkeit („Dependable“) wie folgt erstellen:

//// tab | Python 3.10+

```Python hl_lines="8-9"
{!> ../../docs_src/dependencies/tutorial005_an_py310.py!}
```

////

//// tab | Python 3.9+

```Python hl_lines="8-9"
{!> ../../docs_src/dependencies/tutorial005_an_py39.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="9-10"

## Провайдер зависимости

Можно создать первую зависимость следующим образом:

//// tab | Python 3.10+

```Python hl_lines="8-9"
{!> ../../docs_src/dependencies/tutorial005_an_py310.py!}
```

////

//// tab | Python 3.9+

```Python hl_lines="8-9"
{!> ../../docs_src/dependencies/tutorial005_an_py39.py!}
```

////

//// tab | Python 3.6+

```Python hl_lines="9-10"

## Primeira dependência "injetável"

Você pode criar uma primeira dependência (injetável) dessa forma:

//// tab | Python 3.10+

```Python hl_lines="8-9"
{!> ../../docs_src/dependencies/tutorial005_an_py310.py!}
```

////

//// tab | Python 3.9+

```Python hl_lines="8-9"
{!> ../../docs_src/dependencies/tutorial005_an_py39.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="9-10"

    checkFromStringCase("", 88, "", 88, false);
    checkFromStringCase(":", 99, "", 99, false);
    checkFromStringCase(":123", -1, "", 123, true);
    checkFromStringCase("\nOMG\t", 89, "\nOMG\t", 89, false);
  }

  private static void checkFromStringCase(
      String hpString,
      int defaultPort,
      @Nullable String expectHost,
      int expectPort,
      boolean expectHasExplicitPort) {

ECL0094=IllegalArgumentException occurred when value({7}) of class {5}[{6}] is set to {2}[{3}] field({4}) of class({0})[{1}]. Target class is ({8})[{9}].
ECL0097=Value({1}) of property({0}) can not be converted. because {2}.
ECL0098=Exception occurred when value({7}) of class{5}[{6}] is set to {2}[{3}] property({4}) of class({0})[{1}]. Target class is ({8})[{9}].
ECL0099=Field({1}) of class({0}) is not a static field.
ECL0100=Method({1}) of class({0}) is not a static method.

        }

        in 3..4 -> {
          source.readData(data)
        }

        in 5..7 -> {
          data.writeByte('\n'.code) // 'data' on a line of its own.
        }

        in 8..9 -> {
          id = source.readUtf8LineStrict().takeIf { it.isNotEmpty() }
        }

        in 10..12 -> {
          id = null // 'id' on a line of its own.
        }

        in 13..14 -> {

# 🎧-🔗

👆 💪 ✍ 🔗 👈 ✔️ **🎧-🔗**.

👫 💪 **⏬** 👆 💪 👫.

**FastAPI** 🔜 ✊ 💅 🔬 👫.

## 🥇 🔗 "☑"

👆 💪 ✍ 🥇 🔗 ("☑") 💖:

//// tab | 🐍 3️⃣.6️⃣ & 🔛

```Python hl_lines="8-9"
{!> ../../docs_src/dependencies/tutorial005.py!}
```

////

//// tab | 🐍 3️⃣.1️⃣0️⃣ & 🔛

```Python hl_lines="6-7"
{!> ../../docs_src/dependencies/tutorial005_py310.py!}
```

////

# 子依赖项

FastAPI 支持创建含**子依赖项**的依赖项。

并且，可以按需声明任意**深度**的子依赖项嵌套层级。

**FastAPI** 负责处理解析不同深度的子依赖项。

### 第一层依赖项

下列代码创建了第一层依赖项：

```Python hl_lines="8-9"
{!../../docs_src/dependencies/tutorial005.py!}
```

这段代码声明了类型为 `str` 的可选查询参数 `q`，然后返回这个查询参数。

这个函数很简单（不过也没什么用），但却有助于让我们专注于了解子依赖项的工作方式。

### 第二层依赖项

接下来，创建另一个依赖项函数，并同时用该依赖项自身再声明一个依赖项（所以这也是一个「依赖项」）：

```Python hl_lines="13"

    - [Client Binaries](#client-binaries-5)
    - [Server Binaries](#server-binaries-5)
    - [Node Binaries](#node-binaries-5)
  - [Changelog since v1.8.9](#changelog-since-v189)
    - [Other notable changes](#other-notable-changes-5)
- [v1.8.9](#v189)
  - [Downloads for v1.8.9](#downloads-for-v189)
    - [Client Binaries](#client-binaries-6)
    - [Server Binaries](#server-binaries-6)
    - [Node Binaries](#node-binaries-6)