<div class="termy">

```console
// Aqui ainda não definimos a env var
$ python main.py

// Por isso obtemos o valor padrão

Hello World from Python

// Mas se definirmos uma variável de ambiente primeiro
$ export MY_NAME="Wade Wilson"

// E executarmos o programa novamente
$ python main.py

// Agora ele pode ler a variável de ambiente

Hello Wade Wilson from Python
```

</div>

```
.
├── app
│   ├── __init__.py
│   ├── main.py
│   └── test_main.py
```

The file `main.py` would have:

{* ../../docs_src/async_tests/main.py *}

The file `test_main.py` would have the tests for `main.py`, it could look like this now:

{* ../../docs_src/async_tests/test_main.py *}

## Run it { #run-it }

```
.
├── app
│   ├── __init__.py
│   ├── main.py
│   └── test_main.py
```

Die Datei `main.py` hätte als Inhalt:

{* ../../docs_src/async_tests/main.py *}

Die Datei `test_main.py` hätte die Tests für `main.py`, das könnte jetzt so aussehen:

{* ../../docs_src/async_tests/test_main.py *}

## Es ausführen

   <span style="background-color:#007166"><font color="#D3D7CF"> module </font></span>  🐍 main.py

     <span style="background-color:#007166"><font color="#D3D7CF"> code </font></span>  Importing the FastAPI app object from the module with the
             following code:

 [AccessHeadersJava]: https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/AccessHeaders.java
 [AccessHeadersKotlin]: https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/kt/AccessHeaders.kt
 [PostStringJava]: https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/PostString.java

```
.
├── app
│   ├── __init__.py
│   └── main.py
```

`main.py` 파일 안에 **FastAPI** app 을 만들었습니다:

{* ../../docs_src/app_testing/main.py *}

### 테스트 파일

테스트를 위해 `test_main.py` 라는 파일을 생성할 수 있습니다. 이 파일은 동일한 Python 패키지(즉, `__init__.py` 파일이 있는 동일한 디렉터리)에 위치할 수 있습니다.

``` hl_lines="5"
.
├── app
│   ├── __init__.py
│   ├── main.py
│   └── test_main.py
```

# 第一步

最簡單的 FastAPI 檔案可能看起來像這樣：

{* ../../docs_src/first_steps/tutorial001.py *}

將其複製到一個名為 `main.py` 的文件中。

執行即時重新載入伺服器（live server）：

<div class="termy">

```console
$ <font color="#4E9A06">fastapi</font> dev <u style="text-decoration-style:single">main.py</u>
<font color="#3465A4">INFO    </font> Using path <font color="#3465A4">main.py</font>

```

</div>

➡️ 👀 ⚫️❔ 🔠 👈 🎛 ⛓:

* `main:app`: 👉 🎏 ❕ ⚙️ Uvicorn, `main` ⛓ 🐍 🕹 📛 "`main`",, 📁 `main.py`. &amp; `app` 📛 🔢 👈 **FastAPI** 🈸.
    * 👆 💪 🌈 👈 `main:app` 🌓 🐍 `import` 📄 💖:

        ```Python
        from main import app
        ```

    * , ❤ `main:app` 🔜 🌓 🐍 `import` 🍕 `from main import app`.
* `--workers`: 🔢 👨‍🏭 🛠️ ⚙️, 🔠 🔜 🏃 Uvicorn 👨‍🏭, 👉 💼, 4️⃣ 👨‍🏭.

All the code blocks can be copied and used directly (they are actually tested Python files).

To run any of the examples, copy the code to a file `main.py`, and start `fastapi dev` with:

<div class="termy">

```console
$ <font color="#4E9A06">fastapi</font> dev <u style="text-decoration-style:solid">main.py</u>

  <span style="background-color:#009485"><font color="#D3D7CF"> FastAPI </font></span>  Starting development server 🚀

<div class="termy">

```console
$ <font color="#4E9A06">fastapi</font> dev <u style="text-decoration-style:single">main.py</u>
<font color="#3465A4">INFO    </font> Using path <font color="#3465A4">main.py</font>
<font color="#3465A4">INFO    </font> Resolved absolute path <font color="#75507B">/home/user/code/awesomeapp/</font><font color="#AD7FA8">main.py</font>